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According to the requirements of the document (YUEJIANKEHAN [2002] No.194) issued by Guangdong Provincial Department of Construction, this code was formulated by Guangdong Provincial Academy of Building Research jointly with the organizations concerned through extensive investigation and study, careful summarization of practice experience and scientific research achievements in testing of building foundation, collection and analysis of opinions and suggestions since the implementation of Technical specification of Guangdong Province for quality inspection of pile foundations (Trial) (YUEJIANKEZI [2000] No.137), DBJ 15-27-2000 Specification for reflected wave testing of piles and DBJ 15-28-2001 Technical specification for pile and diaphragm wall inspection with drilled core and on the basis of widely soliciting for opinions.
This code comprises 18 clauses and 8 annexes, including general provisions, terms and symbols, basic requirements, standard penetration test, dynamic penetration test, cone penetration test, vane shear test, plate loading test, low strain integrity testing, high strain dynamic testing, cross hole sonic logging, core drilling method, single-pile vertical compressive static loading test, single-pile vertical pull-out static loading test, single-pile horizontal static loading test, acceptance test of retaining anchor and soil nail, foundation anchor pull-out test, settlement observation, etc.
Guangdong Provincial Academy of Building Research is in charge of the interpretation of this code. During the process of implementing this code, all relevant organizations are kindly requested to sum up experience carefully in combination with engineering practice, and feed the relevant opinions and suggestions back to Guangdong Provincial Academy of Building Research (address: No.121, Xianlie East Road, Guangzhou City, 510500, China; Fax: 02087250256; Email: xtp@21cn.net).
Contents
1 General provisions 1
2 Terms and symbols 2
2.1 Terms 2
2.2 Symbols 5
3 Basic requirements 9
3.1 General requirements 9
3.2 Requirements for subgrade testing 12
3.3 Requirements of testing of foundation pile and foundation anchor 15
3.4 Requirements for supporting engineering testing 19
3.5 Requirements for foundation testing and settlement observation 20
3.6 Verification testing and expanded testing 21
3.7 Testing result evaluation and testing report 23
4 Standard penetration test 25
4.1 Application scope 25
4.2 Equipment 25
4.3 On-site testing 26
4.4 Testing data analysis and judgment 27
5 Dynamic penetration test 31
5.1 Application scope 31
5.2 Equipment 31
5.3 On-site testing 32
5.4 Testing data analysis and judgment 32
6 Cone penetration test 36
6.1 Application scope 36
6.2 Instruments and equipment 36
6.3 On-site testing 37
6.4 Test data analysis and judgment 39
7 Vane shear test 43
7.1 Application scope 43
7.2 Instruments and equipment 43
7.3 On-site testing 44
7.4 Test data analysis and judgment 47
8 Plate loading test 50
8.1 Application scope 50
8.2 Instruments and equipment and their installation 50
8.3 On-site testing 52
8.4 Testing data analysis and judgment 54
9 Low strain integrity testing 57
9.1 Application scope 57
9.2 Instruments and equipment 57
9.3 On-site testing 58
9.4 Testing data analysis and judgment 61
10 High strain dynamic testing 66
10.1 Application scope 66
10.2 Instruments and equipment 66
10.3 On-site testing 67
10.4 Testing data analysis and judgment 69
11 Cross hole sonic logging 75
11.1 Application scope 75
11.2 Instruments and equipment 75
11.3 Embedding of sonic logging pipe 76
11.4 On-site testing 77
11.5 Testing data analysis and judgment 79
12 Core drilling method 90
12.1 Application scope 90
12.2 Equipment 90
12.3 On-site operation 91
12.4 Core specimen taking and processing 93
12.5 Compressive strength test of core specimen 94
12.6 Testing data analysis and judgment 95
13 Single-pile vertical compressive static loading test 100
13.1 Application scope 100
13.2 Instruments and equipment and their installation 100
13.3 On-site testing 102
13.4 Testing data analysis and judgment 105
14 Single-pile vertical pull-out static loading test 107
14.1 Application scope 107
14.2 Instruments and equipment and their installation 107
14.3 On-site testing 109
14.4 Testing data analysis and judgment 111
15 Single-pile horizontal static loading test 113
15.1 Application scope 113
15.2 Instruments and equipment and their installation 113
15.3 On-site testing 114
15.4 Testing data analysis and judgment 115
16 Acceptance test of retaining anchor and soil nail 118
16.1 Application scope 118
16.2 Instruments and equipment and their installation 118
16.3 On-site testing 120
16.4 Testing data analysis and judgment 122
17 Foundation anchor pull-out test 125
17.1 Application scope 125
17.2 Instruments and equipment and their installation 125
17.3 On-site testing 126
17.4 Test data analysis and judgment 128
18 Settlement observation 129
18.1 Application scope 129
18.2 Observation grade and instruments and equipment 129
18.3 Setting of bench mark and observation point 131
18.4 Site observation 133
18.5 Data analysis and evaluation 134
Annex A Testing record form of building foundation 137
Annex B Statistical calculation method of foundation soil test data 142
Annex C Correction of the blow count of dynamic penetration test 144
Annex D Calibration of cone penetration probe 146
Annex E Treatment of concrete pile head 148
Annex F Installation of sensors for high strain dynamic testing 149
Annex G Pile driving test and pile driving monitoring in high strain dynamic testing 151
G.1 Pile driving test 151
G.2 Hammer stress monitoring of pile shaft 151
G.3 Hammer energy monitoring 153
Annex H Processing and measurement of concrete core specimens 154
Explanation of wording in this code 156
1 General provisions
1.0.1 This code is formulated with a view to improving the testing level of building foundation, unifying the testing methods of building foundation, ensuring the engineering testing quality, and achieving safety, applicability, data accuracy, advanced technology, economic feasibility, and environmental protection.
1.0.2 This code is applicable to the acceptance testing of foundations of construction engineering in Guangdong Province. It may also be referred to for the testing of foundations for other purposes and other industries.
1.0.3 For the testing of building foundation, the testing methods shall be selected reasonably and the testing quantity shall be determined with comprehensive consideration of factors such as geological conditions, foundation design grade, foundation type, construction quality reliability, and characteristics and application scope of various testing methods.
1.0.4 In addition to this code, the testing of building foundation shall also comply with the compulsory provisions of national engineering construction standards.
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2 Terms and symbols
2.1 Terms
2.1.1 subgrade, foundation soils
soil or rock mass supporting the foundation
2.1.2 natural foundation, natural subgrade
subgrade with the foundation directly built on the natural soil (rock) layer without manual treatment, which may be divided into natural soil subgrade and natural rock subgrade
2.1.3 the foundation of treatment soils
subgrade with soil subjected to manual treatment in order to increase the bearing capacity of the subgrade and improve the deformation property or permeability, which includes replacement subgrade, preloaded subgrade, dynamic consolidation subgrade, vibroflotation compaction subgrade without additional backfill materials, grouting subgrade, etc.
2.1.4 composite subgrade, composite foundation
subgrade of which some soil is reinforced or replaced to form a reinforcement that together with the surrounding foundation soil bears the load
2.1.5 foundation pile
single pile in pile foundation
2.1.6 anchor
tensile member composed of tensile materials such as steel bars or steel strands which are arranged in the borehole and whose ends are extended into the stable rock-soil layer, and grouting body in the borehole
2.1.7 retaining anchor
anchor transferring the lateral load borne by the envelop enclosure to the surrounding stable rock-soil layer through the tie effect of the anchor
2.1.8 foundation anchor
anchor transferring the upward vertical load borne by the foundation to the stable rock-soil layer at the bottom of the foundation through the tie effect of the anchor
2.1.9 soil anchor
anchor with anchorage section set in soil stratum
2.1.10 rock anchor
anchor with anchorage section set in rock
2.1.11 soil nail
slender member used to reinforce and anchor the in-situ soil mass at the same time, which, relying on the interfacial adhesion or friction with soil mass, is passively stressed under the condition of deformation of the soil mass to mainly bear the tensile force
2.1.12 standard penetration test (SPT)
an in-situ test method to judge the physical and mechanical properties of soil by pre-driving a standard penetrator 15cm into the bottom of the borehole by using a 63.5kg penetration hammer from a falling distance of 76cm, and then recording the blow count required for driving the penetrator for another 30cm
2.1.13 dynamic penetration test (DPT)
an in-situ test method to judge the physical and mechanical properties of soil according to the blow count required for driving a standard conical probe a certain distance into soil by using a heavy hammer from a certain falling distance
2.1.14 cone penetration test (CPT)
an in-situ test method to judge the physical and mechanical properties of soil according to the penetration resistance of a standard conical probe determined when pressing this probe into soil at a constant speed by static force
2.1.15 vane shear test (VST)
an in-situ test method to determine the undrained shear strength of soil by measuring the resistance moment of soil at the time of being damaged with a standard vane probe inserted into the soil
2.1.16 plate loading test (PLT)
test method for determining the bearing capacity of natural subgrade, the foundation of treatment soils, composite subgrade by applying vertical pressure step by step on the surface of subgrade and measuring the change of subgrade settlement with time
2.1.17 low strain integrity testing
testing method for judging the pile integrity through wave theory analysis based on the velocity-time history curve of the pile top which is obtained by measuring when exciting the pile top with the low-energy transient excitation method
2.1.18 high strain dynamic testing
testing method for judging the vertical compressive bearing capacity of single pile and pile integrity through wave theory analysis based on the velocity-time history curve of the upper part of the pile which is obtained by measuring when impacting the pile top with a heavy hammer
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2.1.19 cross hole sonic logging
testing method for judging the pile integrity and diaphragm wall integrity based on the relative changes of acoustic parameters such as acoustic time, frequency and amplitude attenuation of acoustic waves propagating in concrete medium which are measured by transmitting and receiving acoustic waves between embedded sonic logging pipes
2.1.20 core drilling method
testing method for judging the object integrity, the strength of core specimens, the bottom sediment thickness and the geotechnical properties of bearing stratum by drilling core samples of the vertical reinforcement of composite subgrade, the diaphragm wall, and the cast-in-situ concrete pile and its bearing stratum by drilling machine
2.1.21 static loading test
test method for determining the corresponding vertical compressive bearing capacity, vertical pull-out bearing capacity and horizontal bearing capacity of single pile according to the settlement, uplift displacement or horizontal displacement of the pile top over time which are obtained by observing when applying vertical pressure, vertical uplift force or horizontal thrust onto the pile top step by step
2.1.22 settlement observation
observation method for measuring the change of settlement of buildings (structures) with time
2.1.23 pile integrity
a comprehensive qualitative index reflecting the relative change of pile sectional dimension, and the compactness and continuity of pile material
2.1.24 pile defects
a general name for pile fracture, crack, diameter reduction, mud (sundry) inclusion, cavity, honeycomb, looseness and other phenomena
2.1.25 wave measure line
the connecting line between measuring points in two acoustic measuring channels of a certain testing section
2.1.26 the function value of wave measure line's integrity
value determined according to the acoustic parameters and waveform distortion degree of acoustic waves received on the wave measure line, ranging from 1 to 4, and reflecting the pile concrete quality in the sound field radiation area of the wave measure line
2.1.27 the exponent of pile cross section's integrity grade
an index reflecting the concrete integrity of a pile cross section, ranging from 1 to 4, which is obtained by comprehensively taking into account each function value of wave measure line's integrity on this cross section
2.2 Symbols
2.2.1 Resistance and material properties
c——the propagation velocity of one-dimensional longitudinal stress wave of pile (referred to as “pile shaft wave velocity” for short);
Cu——the undrained shear strength of foundation soil;
E——the elastic modulus of pile shaft;
E0——the modulus of deformation of subgrade;
fak——the characteristic value of subgrade bearing capacity;
fcu——the compressive strength of concrete core specimen;
fs——the side frictional resistance of double bridge probe;
fspk——the characteristic value of bearing capacity of composite subgrade;
m——the proportionality coefficient of foundation soil horizontal resistance coefficient;
N——the corrected blow count of standard penetration test;
N′——the measured blow count of standard penetration test;
Nk——the standard value of blow count of standard penetration test;
N10——the blow count of light dynamic penetration test;
N63.5——the blow count of heavy dynamic penetration test;
N120——the blow count of extra-heavy dynamic penetration test;
Nu——the design value of the axial tensile bearing capacity of anchor;
p——the characteristic value of subgrade bearing capacity;
ps——the specific penetration resistance of single bridge probe;
qc——the cone head resistance of double bridge probe;
Qu——the single-pile vertical ultimate bearing capacity;
Ra——the characteristic value of singe-pile vertical compressive bearing capacity; kN;
Rt——the characteristic value of pull-out bearing capacity of anchor;
v——the sound velocity of pile shaft concrete;
Z——the mechanical impedance of pile shaft section;
μ——the Poisson's ratio of soil;
ρ——the mass density of pile shaft.
2.2.2 Actions and action effects
F——the hammer force;
H——the horizontal force acting on pile shaft in single-pile horizontal static loading test;
Nmax——the maximum test load of anchor;
Pf——the total acting force of shear-damage soil mass;
Q——the vertical compressive load applied onto single pile and subgrade, and the axial tensile load applied onto anchor;
s——the settlement;
U——the uplift load applied in single-pile vertical pull-out static loading test;
V——the velocity of particle motion;
Y0——the horizontal displacement of pile shaft in the horizontal force acting plane in single-pile horizontal static loading test;
δ——the pile top uplift amount and anchor head displacement in single-pile vertical pull-out static loading test.
2.2.3 Geometric parameters
A——the cross-sectional area of pile shaft;
b——the side width of rectangular pile, or the diameter or side width of bearing plate;
b0——the calculated width of pile shaft;
B——the width of pier, or the side width of support;
d——the diameter of pile shaft (outer diameter of pipe pile), or the average diameter of core specimen;
L——the pile length.
2.2.4 Calculation coefficients
Ac——the critical value for judgment of abnormal amplitude in cross hole sonic logging;
Jc——the damping coefficient for CASE method;
α——the correction coefficient, the friction-resistance ratio (%), or the horizontal deformation coefficient of pile;
β——the pile integrity coefficient for high strain dynamic testing;
λ——the coefficient corresponding to different statistical numbers in the sample;
vy——the horizontal displacement coefficient of pile top;
ξ——the conversion coefficient for compressive strength of concrete core specimen.
2.2.5 Others
Ap——the acoustic wave amplitude;
α——the peak voltage of the first wave of acoustic wave signal;
f——the frequency;
n——the sample size;
T——the signal period;
t——the time;
v0——the abnormal judgment value of sound velocity;
v01——the judgment value of abnormal small value;
v02——the judgment value of abnormal large value;
vc——the critical value for judgment of abnormal sound velocity;
vL——the low limit value of sound velocity of pile shaft concrete;
Δf——the frequency difference between adjacent peaks on the frequency domain curve;
Δt——the time difference between the incident wave peak and the reflected wave peak.
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3 Basic requirements
3.1 General requirements
3.1.1 For the acceptance of building foundation engineering, quality testing shall be conducted in accordance with those specified in this code.
3.1.2 The testing of building foundation engineering is classified into subgrade testing, foundation pile and foundation anchor testing, supporting engineering testing and foundation testing. The testing methods shall be selected reasonably according to the testing purpose.
1 Subgrade testing. The testing content includes: evaluation of bearing capacity, deformation parameters and geotechnical properties of natural subgrade; evaluation of bearing capacity, deformation parameters and construction quality of the foundation of treatment soils; and evaluation of bearing capacity, deformation parameters and reinforcement construction quality of composite subgrade. The testing methods may be selected from plate loading test, core drilling method, standard penetration test, dynamic penetration test, cone penetration test, vane shear test, geotechnical test, low strain integrity testing, deep plate loading test and rock foundation loading test.
2 Foundation pile and foundation anchor testing. The testing content includes: pile integrity and bearing capacity testing of engineering pile, and pull-out bearing capacity testing of foundation anchor. The pile integrity testing may be conducted with core drilling method, cross hole sonic logging, high strain dynamic testing, low strain integrity testing, etc. The single-pile vertical compressive bearing capacity testing may be conducted with single-pile vertical compressive static loading test and high strain dynamic testing; the single-pile vertical pull-out bearing capacity testing may be with single-pile vertical pull-out static loading test; the single-pile horizontal bearing capacity testing may be with single-pile horizontal static loading test; the pull-out bearing capacity testing of foundation anchor may be with foundation anchor pull-out test.
3 Supporting engineering testing. The testing content includes: pull-out force testing of soil nail and retaining anchor, construction quality testing of soil nail wall, integrity testing of cement-soil wall, quality testing of diaphragm wall, construction quality testing of reverse arch wall, and pile integrity testing of cast-in-situ concrete pile for supporting. The testing methods may be selected from acceptance test of soil nail and retaining anchor, core drilling method, cross hole sonic logging, and low strain integrity testing.
4 Foundation testing. The testing content includes: construction quality testing of various foundations and pile caps, and building settlement observation. Concrete strength may be tested with structural core drilling method and rebound method.
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3.1.3 The testing work procedures shall be carried out in accordance with Figure 3.1.3.
Figure 3.1.3 Block diagram of testing work
3.1.4 Investigation and data collection should include:
1 Collecting geotechnical investigation data, foundation design and construction data of the tested engineering; understanding the construction technology and the abnormal conditions during construction.
2 Further clarifying the specific requirements of the entrusting party.
3 Analyzing the feasibility of on-site implementation of testing items.
3.1.5 The testing unit shall select the testing methods and formulate the testing plan according to the investigation results and the determined testing purpose. The testing plan should include the engineering overview, testing methods and applicable specifications and standards, testing quantity, sampling plan, the required mechanical equipment and manpower coordination, and test time requirements, and shall also include the requirements of pile head excavation, reinforcement, treatment, site leveling, road construction, water supply and power supply, etc. where necessary.
Where it is judged that the selected testing method cannot meet the testing purpose based on the results of the on-site test, the testing method shall be re-selected and a testing plan should be developed. The testing results that fail to fully meet the testing purpose shall not be included in the sampling quantity.
3.1.6 The sampling quantity for acceptance testing of foundation engineering shall be calculated according to unit works. When a unit work is composed of several sub-unit works, the sampling quantity should be calculated according to the sub-unit works.
If different foundation types are used in the same unit work, the testing methods and sampling quantity shall be determined separately. If different pile types or different subgrade treatment methods are adopted in the same unit work, the testing methods and sampling quantity should be determined respectively.
For a residential area work with the foundation design grade of Grade C and the total number of engineering piles being less than 30 or the subgrade treatment area being less than 300m2 in each unit work, several unit works with similar geological conditions and the same construction technology may be combined to determine the sampling quantity upon joint confirmation by the responsible subjects of all parties involved in work quality, but each unit work shall be subjected to sampling testing for bearing capacity, of which the sampling quantity shall not be less than: 1 pile in case of static loading test, 2 piles in case of high strain dynamic testing, and 2 points in case of plate loading test.
For a large-scale unit work with the subgrade treatment area exceeding 20,000m2 or the total number of engineering piles exceeding 2,000, the sampling quantity of the excess part may be appropriately reduced, but it shall not be less than 50% of the corresponding prescribed sampling quantity.
The repaired pile and reinforced pile shall be subjected to sampling testing.
3.1.7 When the testing data is abnormal or there is doubt about the testing results, the reasons shall be found and the testing shall be conducted again if necessary. Standard penetration test, cone penetration test, dynamic penetration test and vane shear test may be carried out again at the point near the original test hole, while low strain integrity testing, high strain dynamic testing and cross hole sonic logging may be carried out again on the original tested pile.
3.1.8 The measuring instruments for testing shall be calibrated. The performance of instruments and equipment shall meet the technical requirements of corresponding testing methods.
When the instruments and equipment are being used, the relevant parameters shall be set according to the calibration results.
Before testing, the instruments and equipment shall be inspected and debugged; during testing, the inspection on instruments and equipment shall be strengthened. The instruments and equipment shall be calibrated where necessary before and during testing.
3.1.9 During on-site testing, in addition to the relevant requirements of this code, the relevant regulations of the nation on safety production shall also be complied with; when the on-site operation environment does not meet the use requirements of instruments and equipment, effective measures shall be taken to ensure the normal operation of instruments and equipment.
3.2 Requirements for subgrade testing
3.2.1 The natural soil subgrade, foundation of treatment soils and composite subgrade shall be subjected subgrade testing by two or more testing methods reasonably, and the testing shall follow the principle of from simple to complex, from thick to fine, and from surface before point.
3.2.2 The testing of the foundation of treatment soils and the composite subgrade should be carried out with a reasonable intermittent time.
3.2.3 The sampling position for subgrade testing shall be comprehensively determined according to the following conditions:
1 The part where any abnormal condition occurs during construction;
2 The part deemed important by the design;
3 The part with complicated local geotechnical characteristics that may affect the construction quality;
4 When two or more testing methods are adopted, the sampling position of the latter method shall be determined according to the testing results of the former method;
5 The sampling positions of similar subgrades should be evenly distributed.
3.2.4 The natural rock subgrade shall be subjected to sampling testing with core drilling method, and the sampling quantity per unit work shall not be less than 6 holes, the drilling depth shall meet the design requirements, and a group of three core specimens shall be taken from the core sample of each hole. For the natural rock subgrade work with complex characteristics, the number of sampling holes shall be increased. When the rock core sample cannot be made into core specimen, rock foundation loading test shall be carried out, and plate loading test should be adopted for strongly weathered rock and completely weathered rock, and the number of test points shall not be less than 3.
3.2.5 The natural soil subgrade and the foundation of treatment soils shall be subjected to plate loading test, and the sampling quantity for unit work shall be neither less than 1 point per 500m2 nor less than 3 points. For complex sites or important building foundations, the sampling quantity shall be increased.
3.2.6 Before plate loading test, the natural soil subgrade and the foundation of treatment soils shall be subjected to a general testing for their treatment quality or the natural foundation soil properties by one or more methods among standard penetration test, dynamic penetration test, cone penetration test and vane shear test according to the subgrade type, and the sampling quantity shall be neither less than 1 hole per 200m2 nor less than 10 holes for unit work, shall not be 1 hole for each independent plinth, and shall not be less than 1 hole per 20 linear meters for foundation trench. The testing depth shall meet the design requirements.
When there is no engineering practice experience available, the testing may be carried out according to the following requirements:
1 After the foundation trench (pit) of natural subgrade is excavated, the foundation trench (pit) may be tested by standard penetration test, dynamic penetration test, cone penetration test or other methods.
2 The replacement subgrade (including lime-soil subgrade, sand and sandstone subgrade, geosynthetic subgrade, flyash subgrade) may be tested by dynamic penetration test or standard penetration test.
The replacement subgrade must be tested for its compacting factor by layers with the cutting-ring method, sand filling method, water filling method or other methods specified in GB/T 50123 Standard for geotechnical testing method, and the sampling quantity shall not be less than: 1 point per 50~100m2 in case of large foundation pit, 1 point per 10~20m in case of foundation trench, and 1 point for each independent plinth.
3 The preloaded subgrade may be tested by vane shear test and indoor geotechnical test.
4 The dynamic consolidation subgrade may be tested by in-situ testing and indoor geotechnical test.
5 The vibroflotation compaction subgrade without additional backfill materials may be tested by dynamic penetration test, standard penetration test or other methods.
6 The grouting subgrade may be tested by standard penetration test and core drilling method.
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3.2.7 The composite subgrade and the dynamic replacement pier shall be subjected to the plate loading test of composite subgrade, and the sampling quantity for unit work shall be 0.5%~1% of the total number of piles (piers) but no less than 3 points. The plate loading test of composite subgrade of the same unit work may be carried out in the form of plate loading test of multi-pile composite subgrade or that of single-pile (pier) composite subgrade, or in the form of plate loading test of multi-pile composite subgrade at some test points and plate loading test of single-pile composite subgrade at the other test points.
3.2.8 Before the plate loading test, the composite subgrade and the dynamic replacement pier shall be tested for the pile shaft construction quality of composite subgrade with appropriate testing method, and the sampling quantity shall be: 0.5%~1% of the total number of piles (piers) but no less than 3 for the unit work in the case that standard penetration test, dynamic penetration test and other methods are adopted; neither less than 0.5% of the total number of piles nor less than 3 in the case that single-pile vertical compressive static loading test and core drilling method are adopted. The testing methods and sampling quantity shall also meet the following requirements:
1 Cement-soil mixing pile and vertical load-bearing jet grouting pile shall be subjected to single-pile vertical compressive loading test;
2 The construction quality of cement-soil mixing pile and jet grouting reinforcement shall be tested by core drilling method;
3 The cement flyash gravel pile shall be subjected to pile integrity testing by low strain integrity testing or core drilling method, and the sampling quantity of low strain integrity testing shall not be less than 10% of the total number of piles;
4 The shaft quality of vibroflotation pile shall be tested by dynamic penetration test or single-pile loading test. The shaft quality of gravel pile shall be tested by heavy dynamic penetration test;
5 The shaft quality of sand-gravel pile shall be tested by dynamic penetration test or other methods. The sand-gravel pile should be subjected to single-pile loading test;
6 The dynamic replacement subgrade shall be tested by dynamic penetration test or other methods.
3.2.9 When required by the design, the soil between piles of composite subgrade and soil between dynamic replacement piers shall be subjected to sampling testing, and the testing methods and sampling quantity should refer to those specified in 3.2.5 and 3.2.6.
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3.3 Requirements of testing of foundation pile and foundation anchor
3.3.1 The acceptance of engineering piles shall include pile integrity testing and single-pile bearing capacity testing.
The pile integrity testing should be carried out first and then the bearing capacity testing be carried out; when the buried depth of foundation is large, the pile integrity testing should be carried out after the foundation pit is excavated to the base elevation.
3.3.2 The intermittent time from pile formation to the start of the test shall meet the following requirements:
1 When the low strain integrity testing or the cross hole sonic logging is adopted, the concrete strength of the pile shaft to be tested shall not be less than 70% of the design strength grade or the strength of the reserved test cube shall not be less than 15MPa.
2 When the core drilling method is adopted, the concrete age of the pile to be tested shall not be less than 28d or the strength of the reserved test cube shall not be less than design strength grade.
3 The intermittent time of high strain dynamic testing and static loading test shall be as follows: the concrete age of cast-in-situ concrete pile shall not be less than 28d; in case of precast pile (steel pile), the intermittent time after pile formation should not be less than 7d for sandy soil, 10d for silty soil, 15d for unsaturated cohesive soil, 25d for saturated cohesive soil, and 25d for pile tip bearing stratum which is weathered rock easy to soften when exposed to water.
3.3.3 The piles subject to sampling testing for pile integrity and single-pile bearing capacity should be comprehensively determined according to the following conditions:
1 Pile with questionable construction quality;
2 Pile deemed important by the design;
3 Pile with abnormal local geological conditions;
4 When two or more testing methods are adopted, the to-be-tested piles of the latter method should be determined according to the testing results of the former method;
5 The piles of the same type should be evenly distributed.
3.3.4 The sampling quantity of the pile integrity testing for cast-in-situ concrete pile shall meet the following requirements:
1 For three-pile or less cap under column, the sampling quantity of piles per cap shall not be less than 1.
2 When one of the following conditions is met, the sampling quantity of piles for four-pile or more cap under column shall not be less than 30% of the total number of piles, and the total number of piles tested for unit work shall not be less than 20.
1) Foundation pile work with foundation design grade A;
2) Pile foundation work with complex geological conditions on site;
3) Pile foundation work with low reliability of construction quality caused by construction technology;
4) New pile types adopted in this area or pile foundation work constructed by new technology.
For other works, the sampling quantity of piles for four-pile or more cap under column shall not be less than 20% of the total number of piles, and the total number of piles tested for unit work shall not be less than 10.
3 For end-bearing cast-in-situ concrete piles with a diameter greater than or equal to 800mm, some of the tested piles shall be subjected to pile integrity testing by core drilling method or cross hole sonic logging, and the sampling quantity shall not be less than 10% of the total number of piles, within the range specified in the above two items.
4 When the test data is inadequate to evaluate the quality of the whole tested pile shaft and the integrity grade of the pile shaft cannot be determined, this pile shall not be included in the sampling quantity of piles specified in the above three items, and the tested piles shall be re-determined or the testing method shall be re-selected to ensure that the sampling quantity of piles meets the requirements of this subclause.
3.3.5 The single-pile vertical compressive bearing capacity testing for cast-in-situ concrete pile shall meet the following requirements:
1 In case of static loading test, the sampling quantity shall be neither less than 1% of the total number of piles nor less than 3; if the total number of piles is less than 50, the sampling quantity shall not be less than 2. In case of high strain dynamic testing, the sampling quantity shall be neither less than 5% of the total number of piles nor less than 5.
2 Under one of the following conditions, the single-pile vertical compressive bearing capacity testing shall be carried out by static loading test:
1) Foundation pile work with foundation design grade A;
2) Pile foundation work with complex geological conditions on site;
3) Pile foundation work with low reliability of construction quality caused by construction technology;
4) There are obvious pile defects, which have an influence on the bearing capacity of the pile shaft structure, and it is difficult to determine the degree of influence by using the integrity testing method;
5) New pile types adopted in this area or pile foundation work constructed by new technology.
3 For end-bearing cast-in-situ concrete piles with a diameter greater than or equal to 1,500mm, if it is difficult to carry out single-pile vertical compressive bearing capacity testing due to the limitation of test equipment or site conditions upon joint confirmation by the responsible subjects of all parties involved in work quality, the pile integrity testing and the identification of pile tip bearing stratum shall be carried out, for which the testing methods shall be core drilling method, cross hole sonic logging or high strain dynamic testing. The total sampling quantity of piles shall meet the requirements of 3.3.4, among which the sampling quantity for core drilling method shall be neither less than 10% of the total number of piles nor less than 10. If the rock foundation loading test (no less than 3 points) has been carried out before pile formation, the total sampling quantity of piles may be reduced by 2%.
3.3.6 The pile integrity testing and single-pile vertical compressive bearing capacity testing for precast piles shall meet the following requirements:
1 When conditions permit, the pile integrity should be tested by using in-hole camera or by putting a low-voltage bulb into the inner cavity of pipe pile.
2 For precast pile work meeting one of the following conditions, the pile integrity testing and single-pile vertical compressive bearing capacity testing shall be carried out by low strain integrity testing and static loading test respectively, and the sampling quantity for integrity testing shall not be less than 20% of the total number of piles, and that for static loading test shall be neither less than 1% of the total number of piles not less than 3; if the total number of piles is less than 50, the sampling quantity shall not be less than 2.
1) Pile foundation work with karst geological conditions on site;
2) Precast pile work in non-karst area, of which the overlying soil stratum is soft soil stratum such as sludge, and under which it is moderately weathered rock or slightly weathered rock, or only thin strongly weathered rock on the moderately weathered rock surface;
3) The pile tip bearing stratum is weathered rock stratum that is easy to soften when exposed to water;
4) Pile foundation work constructed by "pre-augering method".
3 For precast pile works other than those specified in Item 2 of this subclause, the pile integrity testing and single-pile vertical compressive bearing capacity testing shall be carried out at the same time with the high strain dynamic testing, for which the sampling quantity shall be neither less than 8% of the total number of piles under the same conditions nor less than 10. For Grade B pipe pile foundation works with foundation design grade A and complex geological conditions, the sampling quantity shall be increased by 1%. For the pile foundation works that meet one of the following conditions, the sampling quantity may be reduced by 1%:
1) Pile foundation work of which the welds have been subjected to sampling testing according to relevant specifications;
2) Prestressed pipe pile work which has been subjected to pile integrity testing with in-hole camera or low-voltage bulb, with a sampling quantity exceeding 80% of the total number of engineering piles, but has no obvious quality defects found;
3) Prestressed pipe pile work with mechanical joints;
4) Pile foundation work with automatic pile driving recording equipment for construction record during the construction process.
Note: In the case that high strain dynamic testing is not used for sampling testing, the testing method and the sampling quantity of piles shall meet the requirements of Item 2 in this subclause.
3.3.7 The steel piles shall be tested by high strain dynamic testing and static loading test. For high strain dynamic testing, the sampling quantity shall be neither less than 5% of the total number of piles nor less than 10; for static loading test, the sampling quantity shall be neither less than 0.5% of the total number of piles nor less than 3, and if the total number of piles is less than 50, the sampling quantity shall not be less than 2.
3.3.8 For the engineering piles of which the pile driving process is monitored by high strain dynamic testing or the test piles subjected to static loading test before construction, if the construction technology of test piles is the same as that of engineering piles and the pile shaft is undamaged and the single-pile vertical compressive bearing capacity is greater than or equal to 2 times the characteristic value of singe-pile vertical compressive bearing capacity, half of this kind of test piles may be included in the sampling quantity for acceptance test with the same method.
3.3.9 The pile foundation work that has design requirements for vertical pull-out bearing capacity shall be subjected to the single-pile vertical pull-out static loading test. The sampling quantity of piles shall be neither less than 1% of the total number of piles nor less than 3.
3.3.10 The pile foundation work that has design requirements for horizontal bearing capacity shall be subjected to the single-pile horizontal static loading test. The sampling quantity of piles shall be neither less than 1% of the total number of piles nor less than 3.
3.3.11 The foundation anchors shall be subjected to pull-out test, for which the sampling quantity shall be neither less than 5% of the total number of anchors nor less than 6.
3.4 Requirements for supporting engineering testing
3.4.1 The retaining anchors shall be subjected to acceptance test, for which the sampling quantity shall be neither less than 5% of the total number of anchors nor less than 6.
3.4.2 For the purpose of quality acceptance, the soil nail wall shall be subjected to soil nail pull-out test, for which the sampling quantity shall be 0.5%~1% of the total number of soil nails but shall not be less than 10. The thickness of shotcrete on wall surface shall be tested by drilling method, and the sampling quantity should be one group per 100m2 wall area, with no less than 3 points in each group.
3.4.3 The cast-in-situ concrete piles for supporting shall be subjected to pile integrity testing, for which the sampling quantity should be neither less than 10% of the total number of piles nor less than 10, and the testing method may be low strain integrity testing; if pile defects judged by low strain integrity testing possibly affect the horizontal bearing capacity of the pile, supplementary testing shall be conducted with core drilling method, and the sampling quantity should be neither less than 2% of the total number of piles nor less than 3.
3.4.4 The cement-soil wall shall be subjected to integrity testing by the core drilling method, the sampling quantity should be neither less than 1% of the total number of piles nor less than 5, and core sample shall be taken for compressive strength test.
3.4.5 The diaphragm wall shall be tested for integrity with cross hole sonic logging and core drilling method. When the diaphragm wall is part of a permanent structure, the sampling quantity shall be neither less than 20% of the total number of groove sections nor less than 3 groove sections; when the diaphragm wall is a temporary structure, the sampling quantity shall be neither less than 10% of the total number of groove sections nor less than 3 groove sections.
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3.4.6 The construction quality of reverse arch wall shall be tested, for which the sampling quantity shall be one group per 100m2 wall surface, with no less than 3 points in each group, and the testing method may be structural core drilling method.
3.5 Requirements for foundation testing and settlement observation
3.5.1 The spread foundation, strip foundation under column, raft foundation and pile foundation cap shall be tested for concrete strength, and the sampling quantity for unit work shall be neither less than 10% of the total number of members nor less than 3 members. The testing methods may be core drilling method and rebound method. In case of core drilling method, the number of core drilling holes shall not be less than 3 per member (not less than 2 for the member with small sectional dimension), and one core specimen shall be taken each hole.
3.5.2 The reinforced concrete foundation and pile foundation cap should be tested for the protective cover thickness, and the sampling quantity for unit work should not less than 10% of the total number of members.
3.5.3 The following buildings shall be subjected to settlement observation until the settlement reaches the stable standard:
1 Buildings with foundation design grade A;
2 Buildings with the design grade of foundation above composite subgrade or soft subgrade being B;
3 Buildings that have serious quality problems on the foundation and have undergone engineering treatment;
4 Adjacent buildings affected by construction;
5 Buildings affected by environmental factors such as groundwater on site;
6 Renovated and expanded engineerings and storey-adding engineerings;
7 Buildings with new foundation or new structure;
8 Buildings whose design requires settlement observation.
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3.6 Verification testing and expanded testing
3.6.1 If there is any objection to the testing results, testing shall be carried out again at the point near the original test point, or verification testing may be carried out on the original tested pile. The sampling quantity for verification testing should be determined according to the actual situation. The verification testing shall meet the following requirements:
1 The subgrade bearing capacity results of standard penetration test, cone penetration test, dynamic penetration test, vane shear test, etc. may be comprehensively analyzed and evaluated according to the results of plate loading test;
2 The shallow defects of pile shaft may be verified by excavation;
3 Precast piles with defects in pile shaft or joint may be verified by high strain dynamic testing. When necessary, horizontal loading test or vertical pull-out static loading test shall be conducted.
4 The testing results of low strain integrity testing may be verified by core drilling method and high strain dynamic testing;
5 If there is any objection to the testing results of cross hole sonic logging, the cross hole sonic logging may be re-conducted, or verification may be conducted on the same foundation pile with core drilling method;
6 Drill hole may be added in the same foundation pile to verify the testing results of core drilling method;
7 The single-pile bearing capacity results of high strain dynamic testing may be verified by single-pile vertical compressive static loading test.
3.6.2 When the testing results do not meet the design requirements, expanded sampling testing shall be carried out, for which the original sampling testing method or the testing method with higher accuracy shall be adopted. In the case that the cross hole sonic logging can't be used for expanded testing because no sonic logging pipe is buried, the core drilling method shall be adopted. The sampling quantity for expanded testing should be twice the number of piles that fail to meet the design requirements:
1 If the sampling testing results of plate loading test, anchor and soil nail test, single-pile bearing capacity test or core drilling method fail to meet the design requirements, expanded testing shall be carried out with a sampling quantity twice the number of members that fail to meet the design requirements.
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2 If the sum of Grades III and IV piles found in pile integrity testing by low strain integrity testing is greater than 20% of the sampling quantity of piles, expanded testing shall be carried out per the original sampling ratio; and if the sum of Grades III and IV piles in two sampling testings is still greater than 20% of the sampling quantity of pile, all piles of this batch shall be tested. If not, the treatment scheme or the method and quantity of expanded sampling testing shall be studied and determined.
3 If the sum of Grades III and IV piles found in pile integrity testing by high strain dynamic testing and cross hole sonic logging is greater than 20% of the sampling quantity of piles, expanded testing shall be carried out per the original sampling ratio. If not, the treatment scheme or the method and quantity of expanded sampling testing shall be studied and determined.
4 If more than 30% of the testing holes for standard penetration test, dynamic penetration test, cone penetration test, vane shear test or other methods fail to meet the design requirements, expanded testing shall be carried out with a sampling quantity twice the number of holes failing to meet the design requirements, or the number of holes for plate loading test shall be appropriately increased.
5 If the concrete strength testing results of spread foundation, strip foundation under column, raft foundation and pile foundation cap fail to meet the design requirements, expanded testing shall be carried out with a sampling quantity twice the number of members failing to meet the design requirements. The testing method should be core drilling method.
Notes: 1 When the testing results of precast pile fail to meet the design requirements, all the precast piles may be re-driven or re-pressed, and then sampling testing shall be carried out again according to the requirements of 3.5;
2 When the testing results meet the revised design requirements, expanded sampling testing may not be carried out.
3.6.3 After the verification testing and the first expanded sampling testing, the supervision organization or development organization shall study and determine the treatment scheme or the method and quantity for further sampling testing according to the test results in conjunction with the testing, investigation, design and construction organizations.
If there is any doubt or dispute about the testing results, but the conditions for re-testing and verification testing are not available, the supervision organization or development organization shall study and determine the treatment scheme in conjunction with the testing, investigation, design and construction organizations.
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3.7 Testing result evaluation and testing report
3.7.1 In case of standard penetration test, cone penetration test, dynamic penetration test and vane shear test, the testing result of each test hole and the evaluation results of main soil strata of unit work shall be given.
3.7.2 In case of plate loading test, the characteristic value of bearing capacity at each point and the characteristic value of subgrade bearing capacity of unit work as well as the conclusion whether the characteristic value of subgrade bearing capacity of unit work meeting design requirements shall be given.
3.7.3 The pile integrity testing results shall include the integrity grade of each tested pile. The pile integrity graduation shall be in accordance with those specified in Table 3.7.3 and shall be graded according to the technical contents specified in Clauses 9~12 respectively.
Table 3.7.3 Pile integrity graduation
Pile integrity grade Graduation principle
Grade I pile The pile shaft is integral
Grade II pile There are slight defects in the pile shaft, which will not influence the normal performance of the bearing capacity of the pile shaft structure
Grade III pile There are obvious defects in the pile shaft, which influence the bearing capacity of the pile shaft structure
Grade IV pile There are serious defects in pile shaft
Notes: 1 It is necessary to further determine the degree of influence of the defects in Grade III pile shafts on the bearing capacity of pile shaft structure;
2 Grade IV piles shall be subjected to engineering treatment.
3.7.4 The testing results of the bearing capacity of engineering piles shall include the conclusion whether the bearing capacity of each tested pile meets the design requirements.
3.7.5 If the normal use of the tested pile may be affected after testing, it shall be explained in the testing report.
3.7.6 The testing report shall include accurate conclusions be prepared in standard words. In case of any confusing terms and concepts, the requirements of this code shall prevail.
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3.7.7 The testing report shall cover:
1 Name of the entrusting party, work name, work location, development organization, investigation organization, design organization, supervision organization, construction organization, foundation type, design requirements, testing purpose, testing basis, testing quantity and testing date;
2 Main geotechnical investigation data;
3 The number, position and related construction records of the test object;
4 Main testing instruments and equipment;
5 Testing methods;
6 Actual measurement and calculation analysis charts and testing data summary results;
7 Description of abnormal conditions during testing (if necessary);
8 Testing conclusions.
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4 Standard penetration test
4.1 Application scope
4.1.1 The standard penetration test may be used for the following subgrade testings:
1 Estimate the bearing capacity of natural subgrades such as sandy soil, silty soil, cohesive soil and granite residual soil subgrades, and identify their geotechnical properties.
2 Estimate the bearing capacity of non-gravel soil replacement subgrade, dynamic consolidation subgrade, preloaded subgrade, vibroflotation compaction subgrade without additional backfill materials, grouting subgrade and others of treatment soils, and evaluate the subgrade treatment effect.
3 Evaluate the reinforcement construction quality of composite subgrade.
4.1.2 Identification of geotechnical properties of the bearing stratum at tip of cast-in-situ concrete pile by standard penetration test may be carried out with reference to this Clause.
4.2 Equipment
4.2.1 The equipment for standard penetration test shall be in accordance with those specified in Table 4.2.1.
Table 4.2.1 Specifications of equipment for standard penetration test
Drop hammer Hammer mass (kg) 63.5±0.5
Falling distance (cm) 76±2
Penetrometer Split pipe Length (mm) >500
Outer diameter (mm) 51±1
Inner diameter (mm) 35±1
Pipe shoe Length (mm) 50~76
Blade angle (°) 18~20
Thickness of single blade (mm) 2.5
Drill pipe Diameter (mm) 42~50
Relative bending <0.5%
4.2.2 The standard penetration test shall be carried out by the free-fall hammer method with automatic decoupling.
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4.3 On-site testing
4.3.1 Rotary drilling shall be adopted for standard penetration test holes. When drilling the standard penetration test hole, the water level in the hole shall be kept slightly higher than the groundwater level outside the hole. When the hole wall is unstable, slurry retaining wall may be adopted. The hole shall be drilled to a level 15cm above the test elevation, and then the residual soil at the bottom of hole shall be removed before conducting the test.
4.3.2 The drop hammer height of standard penetration test is 76±2cm, and the blow rate shall be less than 30 blows/min. During the test, the perpendicularity of the penetrator, probe rod and guide rod shall be kept after connection, so as to reduce the friction between the guide rod and hammer and avoid the eccentric hammering and lateral sway.
4.3.3 After the penetrator is driven into the soil for 15cm, start to record the blow count per 10cm of driving depth, and the blow count required for accumulated driving depth of 30cm is the measured blow count of standard penetration test, N′. If the penetration depth is less than 30cm when the blow count has reached 50 blows, the total penetration depth of 50 blows shall be recorded, the measured blow count of standard penetration test, N′, shall be calculated using Formula (4.3.3) and the test shall be terminated.
(4.3.3)
where,
N′——the measured blow count of standard penetration test;
ΔS——the total penetration depth of 50 blows, cm.
Note: When identifying the geotechnical properties of the bearing stratum at tip of cast-in-situ concrete pile, the standard penetration blow count shall reach 100 blows before the test can be terminated.
4.3.4 After the penetrator is pulled out, the soil sample in the penetrator shall be identified and described.
4.3.5 At least three standard penetration tests shall be conducted in each testing hole, the standard penetration test points shall be at equal spacing in the same testing hole, and the depth spacing should be 1.0~1.5m.
When identifying the geotechnical properties of the bearing stratum at tip of cast-in-situ concrete pile, standard penetration test should be conducted within 1m from pile bottom.
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4.3.6 The standard penetration test data may be recorded in the format of Annex A, Table A.0.1.
4.4 Testing data analysis and judgment
4.4.1 To determine the characteristic value of subgrade bearing capacity, the corrected blow count of standard penetration test, N, should be adopted; to judge liquefaction of sandy soil and silty soil and to distinguish the geotechnical properties of soil, the measured blow count of standard penetration test, N′, should be adopted. When rod length correction is required, the blow count shall be corrected against the probe rod length using Formula (4.4.1).
N=αN′ (4.4.1)
where,
N——the corrected blow count of standard penetration test;
N′——the measured blow count of standard penetration test;
α——the correction coefficient for probe rod length, which may be determined according to Table 4.4.1.
Table 4.4.1 Correction coefficient for probe rod length of standard penetration test
Probe rod length (m) ≤3 6 9 12 15 18 21
α 1.00 0.92 0.86 0.81 0.77 0.73 0.70
4.4.2 For natural soil subgrade and foundation of treatment soils, the standard penetration test results shall provide the relationship curve or chart between the corrected blow count of standard penetration test, N, (or the measured blow count of standard penetration test, N′)/soil stratum classification and the depth of each testing hole. For the reinforcement of composite subgrade, the standard penetration test results shall provide the relationship curve or chart between the corrected blow count of standard penetration test, N, and the depth of each testing hole.
4.4.3 The representative value of standard penetration blow count of each testing hole shall be calculated by the averaging method according to the blow counts of standard penetration test at different depths.
1 General provisions
2 Terms and symbols
2.1 Terms
2.2 Symbols
3 Basic requirements
3.1 General requirements
3.2 Requirements for subgrade testing
3.3 Requirements of testing of foundation pile and foundation anchor
3.4 Requirements for supporting engineering testing
3.5 Requirements for foundation testing and settlement observation
3.6 Verification testing and expanded testing
3.7 Testing result evaluation and testing report
4 Standard penetration test
4.1 Application scope
4.2 Equipment
4.3 On-site testing
4.4 Testing data analysis and judgment
5 Dynamic penetration test
5.1 Application scope
5.2 Equipment
5.3 On-site testing
5.4 Testing data analysis and judgment
6 Cone penetration test
6.1 Application scope
6.2 Instruments and equipment
6.3 On-site testing
6.4 Test data analysis and judgment
7 Vane shear test
7.1 Application scope
7.2 Instruments and equipment
7.3 On-site testing
7.4 Test data analysis and judgment
8 Plate loading test
8.1 Application scope
8.2 Instruments and equipment and their installation
8.3 On-site testing
8.4 Testing data analysis and judgment
9 Low strain integrity testing
9.1 Application scope
9.2 Instruments and equipment
9.3 On-site testing
9.4 Testing data analysis and judgment
10 High strain dynamic testing
10.1 Application scope
10.2 Instruments and equipment
10.3 On-site testing
10.4 Testing data analysis and judgment
11 Cross hole sonic logging
11.1 Application scope
11.2 Instruments and equipment
11.3 Embedding of sonic logging pipe
11.4 On-site testing
11.5 Testing data analysis and judgment
12 Core drilling method
12.1 Application scope
12.2 Equipment
12.3 On-site operation
12.4 Core specimen taking and processing
12.5 Compressive strength test of core specimen
12.6 Testing data analysis and judgment
13 Single-pile vertical compressive static loading test
13.1 Application scope
13.2 Instruments and equipment and their installation
13.3 On-site testing
13.4 Testing data analysis and judgment
14 Single-pile vertical pull-out static loading test
14.1 Application scope
14.2 Instruments and equipment and their installation
14.3 On-site testing
14.4 Testing data analysis and judgment
15 Single-pile horizontal static loading test
15.1 Application scope
15.2 Instruments and equipment and their installation
15.3 On-site testing
15.4 Testing data analysis and judgment
16 Acceptance test of retaining anchor and soil nail
16.1 Application scope
16.2 Instruments and equipment and their installation
16.3 On-site testing
16.4 Testing data analysis and judgment
17 Foundation anchor pull-out test
17.1 Application scope
17.2 Instruments and equipment and their installation
17.3 On-site testing
17.4 Test data analysis and judgment
18 Settlement observation
18.1 Application scope
18.2 Observation grade and instruments and equipment
18.3 Setting of bench mark and observation point
18.4 Site observation
18.5 Data analysis and evaluation
Annex A Testing record form of building foundation
Annex B Statistical calculation method of foundation soil test data
Annex C Correction of the blow count of dynamic penetration test
Annex D Calibration of cone penetration probe
Annex E Treatment of concrete pile head
Annex F Installation of sensors for high strain dynamic testing
Annex G Pile driving test and pile driving monitoring in high strain dynamic testing
G.1 Pile driving test
G.2 Hammer stress monitoring of pile shaft
G.3 Hammer energy monitoring
Annex H Processing and measurement of concrete core specimens
Explanation of wording in this code
