标准编号:	DBJ 15-31-2016
中文名称:	建筑地基基础设计规范
英文名称:	Design code for building foundation
行业分类:	DB    地方标准
发布日期:	2016-08-15
实施日期:	2016-12-1
标准状态:	现行
替代旧标准:	DBJ 15-31-2003 建筑地基基础设计规范
翻译语言:	英文
文件格式:	PDF
中文字符数:	185000 字
翻译价格(元):	25000.00 元
交付时间:	付款后 1 个工作日

Codeofchina.com is in charge of this English translation. In case of any doubt about the English translation, the Chinese original shall be considered authoritative.



This code is developed by revising the original Guangdong provincial standard DBJ 15-31-2003 Design code for building foundation by Guangzhou Institute of Building Science, Architectural Design & Research Institute of SCUT, together with relevant design, investigation, construction, scientific research, teaching, inspection and supervision units according to the requirements of Notice on issuing the development and revision plan on engineering construction standards of Guangdong Province in 2014 (YUEJIANKEHAN [2014] No. 1384) issued by the Guangdong Provincial Department of Housing and Urban-Rural Development. The principle of this revision is to keep major issues in accordance with national standards and reflect the mature experience and technical progress in the design, investigation, construction, inspection and supervision of building foundation for more than ten years.



During the revision process, the code drafting group investigated and summarized the practical experience of building foundation engineering in Guangdong Province for more than ten years, carried out special studies, reasonably adopted some new study results, and extensively solicited opinions from relevant design, investigation, construction, inspection and quality supervision as well as scientific research and teaching units throughout the province, to finalize this code through repeated discussion, modification, trial design and review.



This code comprises 13 clauses and 11 annexes. The main revisions are as follows:



1. Division of foundation design grade and safety grade of foundation pit engineering.



2. Where the weathering degree of granite rocks is divided by the measured standard penetration number N ′, 40 ≤ N′ < 70 represents completely weathered, and N ′ ≥ 70 represents strongly weathered, which are consistent with the new geotechnical engineering investigation code.



3. The compressibility of soil is classified according to its compression modulus.



4. The definition of contaminated soil is added.



5. The contents of key geotechnical engineering investigation points are added.



6. The calculation principle for the uplift force and lateral pressure of groundwater on underground structures is specified.



7. The adjustment coefficient of wind-resistant bearing capacity of subgrade is specified.



8. The settlement calculation of overconsolidated or underconsolidated soil layers is added.



9. The reference table for effective reinforcement depth by dynamic compaction method is added.



10. The compaction criteria for various cushions and compacted fill are adjusted according to the actual engineering experience.



11. The bearing capacity revision coefficient of soil between piles in rigid pile composite subgrade is revised.



12. The section with saturated sandy soil overlying bedrock in karst development area is clearly defined as unstable site and is forbidden to be used as the bearing layer of composite subgrade.



13. The design method of rigid pile composite subgrade is added.



14. The calculation method of the shear capacity of spread foundation is added.



15. The calculation method of the flexural capacity of spread foundation is improved.



16. The resistance coefficient C1 at socketed pile end is adjusted from 0.3 ~ 0.5 to 0.4 ~ 0.6.



17. The characteristic value and description of pile side resistance of cast-in-situ bored pile with mud retaining wall in granite stratum are added.



18. The design method of post-grouting pile at pile bottom is added.



19. The calculation equations of the characteristic value of bond strength between rock bolt body and rock and the tensile bearing capacity at normal section of rock bolt are revised.



20. The quality inspection and acceptance methods of large-diameter socketed piles are revised.



21. It is specified that the pressure plate test of strongly-weathered rock shall be carried out according to the requirements of soil layer pressing plate test.



The provisions printed in bold type are compulsory provisions and must be enforced strictly.

Contents



1 General provisions 1

2 Terms and symbols 1

2.1 Terms 1

2.2 Symbols 4

3 Basic requirements 7

4 Geotechnical investigation 12

4.1 General requirements 12

4.2 Classification of rock and soil 14

4.3 Key points of geotechnical investigation 22

4.4 Engineering property indexes 31

4.5 Characteristic value of subgrade bearing capacity 35

4.6 Investigation report 39

5 Groundwater action 42

5.1 General requirements 42

5.2 Anti-floating design of basement 43

5.3 Groundwater control 46

6 Subgrade calculation 47

6.1 Buried depth of foundation 47

6.2 Bearing capacity calculation 48

6.3 Deformation calculation 56

6.4 Stability checking 65

7 Soft subgrade and ground treatment 66

7.1 General requirements 66

7.2 Utilization and treatment 67

7.3 Building measures 73

7.4 Structural measures 74

7.5 Large area ground load 76

7.6 Rigid pile composite subgrade 79

8 Special geology and foundation in mountainous area 83

8.1 General requirements 83

8.2 Soil-rock composite subgrade 84

8.3 Foundation on compacted fill 86

8.4 Landslide prevention 89

8.5 Karst and sinkhole 92

8.6 Side slope and retaining wall 95

9 Shallow foundation 103

9.1 Non-reinforced spread foundation 103

9.2 Spread footing 105

9.3 Strip footing under column 113

9.4 Raft foundation 115

10 Pile foundation 122

10.1 General requirements 122

10.2 Pile foundation design 130

10.3 Structure details of pile foundation 155

10.4 Seismic checking of pile foundation 158

10.5 Pile cap design 159

11 Foundation on rock-anchor system 163

11.1 General requirements 163

11.2 Uplift calculation for rock-anchor foundation 164

12 Retaining and protection for excavations 166

12.1 General requirements 166

12.2 Earth pressure and water pressure 170

12.3 Design calculation for retaining structure 171

12.4 Internal bracing of retaining structure 177

12.5 Soil nails and anchors 180

12.6 Reversed construction method 185

13 Inspection and monitoring 188

13.1 General requirements 188

13.2 Inspection 188

13.3 Monitoring 193

Annex A Key points for shallow plate load test 198

Annex B Key points for deep plate load test 200

Annex C Standard values of shear strength index, c and  202

Annex D Key points for rock subgrade load test 204

Annex E Key points for rock uniaxial compressive strength test 206

Annex F Key points for single-pile vertical compressive static load test 208

Annex G Key points for single-pile horizontal load test 212

Annex H Key points for single-pile vertical uplift static load test 215

Annex J Key points for rock anchor uplift test 218

Annex K Key points for pile side resistance test in bedrock 220

Annex L Key points for standard penetration, portable penetration, vane shear test and heavy dynamic penetration 223

Explanation of wording in this code 229

List of quoted standards 230





Design code for building foundation



1 General provisions



1.0.1 This code is formulated with a view to achieving safety, reliability, advanced technology, economic feasibility and environmental protection and to guaranteeing quality in the building foundation design in Guangdong Province.



1.0.2 This code is applicable to foundation design for industrial and civil buildings, including structures, in Guangdong Province.



1.0.3 This code is formulated according to the current national standards GB 50007 Code for design of building foundation and GB 50021 Code for investigation of geotechnical engineering, in combination with the geological conditions, engineering characteristics and engineering experience of Guangdong Province.



1.0.4 The foundation design shall be based on the foundation design grade and geotechnical engineering investigation data, by comprehensively taking into account factors such as structure type, construction conditions, construction cost, resource conservation and environmental protection, so as to be adaptive to local conditions, reasonable in type selection and well-designed.



1.0.5 In addition to those specified in this code, the building foundation design shall also comply with the requirements of the current relevant standards of the nation.



2 Terms and symbols



2.1 Terms



2.1.1

subgrade; foundation soils

soil or rock mass supporting the foundation



2.1.2

foundation

substructure transmitting various actions borne by the superstructure to the substructure of building on the subgrade



2.1.3

characteristic value of subgrade bearing capacity

pressure value corresponding to the specified deformation in the linear deformation section of the subsoil pressure deformation curve measured by load test, of which the maximum value is the proportional threshold value

2.1.4

revised characteristic value of subgrade bearing capacity

subgrade bearing capacity where the subsoil deformation does not exceed the allowable value under the condition of ensuring the subgrade stability



2.1.5

gravity density, unit weight

gravity borne by rock and soil per unit volume, which is the product of the density of rock and soil and the gravitational acceleration



2.1.6

rock discontinuity structural plane

cracked and easy-to-crack surface in rock mass, such as bedding, joint, fault and schistosity, which is also called discontinuous structural surface



2.1.7

allowable subsoil deformation

deformation control value set to ensure the normal use of building



2.1.8

soil-rock composite subgrade

subgrade with a large slope on the underlying bedrock surface; or subgrade with dense and exposed clints; or subgrade with exposed large boulder or individual clints within the scope of the main stress layer of the building foundation



2.1.9

ground treatment

engineering measure taken to increase the subgrade bearing capacity or improve its deformation or permeability



2.1.10

composite subgrade, composite foundation

artificial subgrade formed by reinforcing or replacing some soil so that the load is borne by both subsoil and reinforcement



2.1.11

spread foundation

foundation with a large bottom area formed by the outward expansion of support cross-section at the root of column and wall, which spreads large compressive stress from the superstructure, so that the compressive stress acting on the foundation meets the design requirements of the subgrade bearing capacity





2.1.12

non-reinforced spread foundation

strip foundation under wall or independent foundation under column, composed of brick, rubble, concrete or rubble concrete, lime soil and trinity mixture fill



2.1.13

strip foundation, strip footing

strip foundation under a wall or column



2.1.14

raft foundation, mat foundation

reinforced concrete slab or ribbed slab foundation supporting the load of the whole structure and having an area not less than the floor area of the building



2.1.15

pile foundation

foundation consisting of a pile socketed in rock and soil and a cap connected to the top of the pile



2.1.16

socketed pile

pile partly entering the rock at the lower part and supported by moderately-weathered and weakly-weathered rock layer



2.1.17

retaining structure

structure built to keep the rock and soil side slope stable, control the displacement, and mainly bear lateral loads



2.1.18

hard rock

rock with saturated uniaxial compressive strength greater than 30MPa



2.1.19

weak rock

rock with saturated uniaxial compressive strength less than or equal to 30MPa



2.1.20

bearing layer, sustaining layer

stratum directly bearing foundation load



2.1.21

compressed layer

generic term of soil layer within the foundation settlement calculation depth

2.1.22

underlying layer

each soil layer located below the bearing layer of the structure foundation and within the range of compression layer



2.1.23

punching failure

continuous sinking failure mode of the foundation caused by the compressive deformation and lateral extrusion of the bearing layer under the foundation load, making the foundation cut into the soil



2.1.24

cushion

sand, gravel, lime soil or plain soil layer, etc. with certain thickness, which is filled on soft subsoil or replaces the upper part of the soft subsoil



2.1.25

softening coefficient of rock

ratio of uniaxial compressive strength of rock in saturated state to uniaxial compressive strength in dry state



2.2 Symbols



A——Area of foundation bottom;



Ap——Sectional area of pile;



a——Compression coefficient;



b——Width of foundation bottom (minimum side length) or side length of the foundation bottom in the moment action direction;



c——Cohesion;



ck——Standard value of soil cohesion;



D——Diameter of pile end enlarged bottom;



d——Foundation buried depth or pile diameter;



Ea——Active soil pressure;



Es——Compressive modulus of soil;



E0——Deformation modulus of soil;



e——Void ratio;



F——Vertical force on the top surface of foundation;



Fk——Vertical force acting on the top surface of foundation in the standard combination of loads;



fa——Revised characteristic value of subgrade bearing capacity, or characteristic value of bearing capacity of rock subgrade;



fak——Characteristic value of subgrade bearing capacity;



frk——Standard value of saturated uniaxial compressive strength of rock;



faz——Characteristic value of subgrade bearing capacity on the top of soft underlying layer;



G——Dead load;



Gk——Standard value of the dead weight of foundation and the weight of soil on the foundation;



H0——Foundation height;



Hf ——Building height calculated from the bottom of foundation;



Hg——Building height calculated from the ground;



L——Length of house or unit length separated by settlement joint;



l——Length of foundation bottom;



M——Design value of the moment acting on the foundation bottom or bending moment of the section;



Mk——Standard value of the bending moment acting on the foundation bottom or bending moment of the section;



Mb, Md, Mc——Bearing capacity coefficient;



m——Proportionality coefficient of soil horizontal resistance coefficient;



N——Revised blow count of standard penetration test;



N′——Measured blow count of standard penetration test;



N63.5——Revised blow count of heavy dynamic penetration test;



——Measured blow count of heavy dynamic penetration test;



n——Number of piles;



pk——Average pressure on foundation bottom in the standard combination of load effects;



p0——Average additional pressure on foundation bottom in the standard combination of load effects;



pz——Additional stress on foundation bottom in the standard combination of load effects;



pcz——Deadweight pressure of soil on the top surface of the weak underlying layer;



Qk——Vertical load in the standard combination of load effects and vertical force borne by a single pile in the pile foundation;



qpa——Characteristic value of the bearing capacity of pile tip soil;



qsa——Characteristic value of the friction of soil around the pile;



Ra——Characteristic value of the vertical bearing capacity of a single pile;



RHa——Characteristic value of singe pile horizontal bearing capacity;



Rta——Characteristic value of singe pile uplift bearing capacity;



St——Sensitivity of soil;



s——Settlement;



u——Peripheral length;



up——Peripheral length of pile body;



W——Resistance moment of foundation bottom;



w——Water content of soil;



wL——Liquid limit;



wp——Plastic limit;



z——Depth from the loading surface of the foundation bottom;



zn——Calculated depth of foundation settlement;



β——Slope angle of the side slope to the horizontal plane;



γ——Gravity density of soil, which is referred to as unit weight;



γm——Weighted mean unit weight of each soil layer in the buried depth of foundation; the effective unit weight shall be taken below the groundwater level;



——Internal friction angle;



δ——Friction angle of soil against the back of retaining wall;



μ——Friction coefficient of soil against the base of retaining wall;



ηb——Revision coefficient of bearing capacity for foundation width;



ηd——Revision coefficient of bearing capacity for foundation buried depth;



θ——Subgrade pressure diffusion angle;



v——Poisson's ratio of soil;



ψf——Regression revision coefficient;



ψs——Empirical coefficient of settlement calculation;



, ——Average additional stress coefficient from calculation point of foundation bottom to bottom of the ith layer of soil and the i-1th layer of soil.



3 Basic requirements



3.0.1 According to the complexity of subgrade, the scale and characteristics of buildings, and the degree of damage or influence on the normal use of buildings due to foundation problems, the foundation design is classified into three grades, which shall be selected according to the specific conditions in the design as per Table 3.0.1.



Table 3.0.1 Foundation design grade

Design grade Type of building and subgrade

Grade A Important industrial and civil buildings;

High-rise buildings above 30 storeys;

Buildings with complex shapes formed by high building and low building connected to each other with the high one 10 storeys more than the low one;

Large-area multi-storey underground buildings (such as underground garages, shopping malls and sports fields);

Buildings with special requirements for subsoil deformation;

Buildings on slopes under complex geological conditions (including high side slopes);

New buildings which have great influence on adjacent buildings;

General buildings with complex site and foundation conditions.

Grade B Industrial and civil buildings other than those of grades A and C

Grade C Civil or general industrial buildings with 7 storeys or less and with simple site and foundation conditions and uniform load distribution; minor light buildings



3.0.2 According to the building foundation design grade and the influence degree of foundation deformation on superstructure under the action of long-term load, the foundation design shall meet the following requirements:



1 The subgrade calculation of all buildings shall meet the relevant requirements of bearing capacity calculation.



2 Buildings with foundation of design grade A and grade B shall be subjected to subgrade deformation calculation.



3 Deformation checking shall be carried out for buildings of design grade C under any of the following circumstances:



1) The characteristic value of subgrade bearing capacity is less than 130kPa, and the building is complex.



2) Where there are ground heaps on the foundation or near the foundation, or where the foundation load differs greatly from that of its adjacent foundation, and may cause excessive uneven settlement of the ground.



3) Where eccentric load exists in buildings on soft foundation.



4) Where adjacent buildings are close to each other and there is possibility for the building to tilt.



5) Where there is filling with large thickness or uneven thickness in the subgrade but its dead weight consolidation is not finished yet.



4 For high-rise building, high-rise structure and retaining wall frequently affected by horizontal load and building & structure built on slope or near side slope, the stability shall also be checked.



5 Stability checking shall be carried out for foundation pit engineering.



6 If there is floating problem in building basement or underground structures, anti-floating checking shall be carried out.



3.0.3 Deformation checking may not be carried out for the following buildings:



1 Building with the shallow foundation bearing layer of moderately- and weakly-weathered rock; building less than fifteen storeys, with strip or raft foundation, and the bearing layer of gravel soil, dense sand, hard plastic to hard residual soil layer or completely-weathered and strongly-weathered rock layer with characteristic value of subgrade bearing capacity ≥300kPa; building with pile foundation and the bearing layer of moderately-weathered rock layer; or building less than 30 storeys and the pile foundation bearing layer of medium-dense sand layer, egg layer and gravel layer (without weak underlying layer), hard plastic to hard residual soil, completely-weathered and strongly-weathered rock layer.

1 General provisions
2 Terms and symbols
2.1 Terms
2.2 Symbols
3 Basic requirements
4 Geotechnical investigation
4.1 General requirements
4.2 Classification of rock and soil
4.3 Key points of geotechnical investigation
4.4 Engineering property indexes
4.5 Characteristic value of subgrade bearing capacity
4.6 Investigation report
5 Groundwater action
5.1 General requirements
5.2 Anti-floating design of basement
5.3 Groundwater control
6 Subgrade calculation
6.1 Buried depth of foundation
6.2 Bearing capacity calculation
6.3 Deformation calculation
6.4 Stability checking
7 Soft subgrade and ground treatment
7.1 General requirements
7.2 Utilization and treatment
7.3 Building measures
7.4 Structural measures
7.5 Large area ground load
7.6 Rigid pile composite subgrade
8 Special geology and foundation in mountainous area
8.1 General requirements
8.2 Soil-rock composite subgrade
8.3 Foundation on compacted fill
8.4 Landslide prevention
8.5 Karst and sinkhole
8.6 Side slope and retaining wall
9 Shallow foundation
9.1 Non-reinforced spread foundation
9.2 Spread footing
9.3 Strip footing under column
9.4 Raft foundation
10 Pile foundation
10.1 General requirements
10.2 Pile foundation design
10.3 Structure details of pile foundation
10.4 Seismic checking of pile foundation
10.5 Pile cap design
11 Foundation on rock-anchor system
11.1 General requirements
11.2 Uplift calculation for rock-anchor foundation
12 Retaining and protection for excavations
12.1 General requirements
12.2 Earth pressure and water pressure
12.3 Design calculation for retaining structure
12.4 Internal bracing of retaining structure
12.5 Soil nails and anchors
12.6 Reversed construction method
13 Inspection and monitoring
13.1 General requirements
13.2 Inspection
13.3 Monitoring
Annex A Key points for shallow plate load test
Annex B Key points for deep plate load test
Annex C Standard values of shear strength index, c and
Annex D Key points for rock subgrade load test
Annex E Key points for rock uniaxial compressive strength test
Annex F Key points for single-pile vertical compressive static load test
Annex G Key points for single-pile horizontal load test
Annex H Key points for single-pile vertical uplift static load test
Annex J Key points for rock anchor uplift test
Annex K Key points for pile side resistance test in bedrock
Annex L Key points for standard penetration, portable penetration, vane shear test and heavy dynamic penetration
Explanation of wording in this code
List of quoted standards

1 总 则
1.0.1 为了在广东省的建筑地基基础设计中做到安全可靠、技术先进、经济合理、保护环境、确保质量，制定本规范。
1.0.2 本规范适用于广东省的工业与民用建筑物(包括构筑物)的地基基础设计。
1.0.3 本规范根据现行国家标准《建筑地基基础设计规范》GB 50007、《岩土工程勘察规范》GB 50021，结合广东地区的地质条件、工程特点和工程经验而制定。
1.0.4 地基基础设计，应根据地基基础设计等级、岩土工程勘察资料，综合考虑结构类型、施工条件、工期造价、节约资源、保护环境等因素，做到因地制宜、选型合理、精心设计。
1.0.5 建筑地基基础的设计除应符合本规范的规定外，尚应符合国家现行有关标准的规定。
2 术语及符号
2.1 术 语
2.1.1 地基 subgrade，foundation soils
支承基础的土体或岩体。
2.1.2 基础 foundation
将上部结构所承受的各种作用传递到地基上的建筑物下部结构。
2.1.3 地基承载力特征值 characteristic value of subgrade bearing capacity
指由载荷试验测定的地基土压力变形曲线线性变形段内规定的变形所对应的压力值，其最大值为比例界限值。
2.1.4 修正后的地基承载力特征值 revised characteristic value of subgrade bearing capacity
指在保证地基稳定的条件下，地基变形不超过允许值的地基承载力。
2.1.5 重力密度(重度) gravity density，unit weight
单位体积岩土所承受的重力，为岩土的密度与重力加速度的乘积。
2.1.6 岩体结构面 rock discontinuity structural plane
岩体内开裂的和易开裂的面，如层面、节理、断层、片理等，又称不连续构造面。
2.1.7 地基变形允许值 allowable subsoil deformation
为保证建筑物正常使用而设定的变形控制值。
2.1.8 土岩组合地基 soil-rock composite subgrade
在建筑地基的主要受力层范围内，有下卧基岩表面坡度较大的地基；或石芽密布并有出露的地基；或大块孤石或个别石芽出露的地基。
2.1.9 地基处理 ground treatment
为提高地基承载力，或改善其变形性质或渗透性质而采取的工程措施。
2.1.10 复合地基 composite subgrade，composite foundation
部分土体被增强或被置换，而形成的由地基土和增强体共同承担荷载的人工地基。
2.1.11 扩展基础 spread foundation
柱、墙根部支承处截面向外扩大，形成较大底面积的基础，将上部结构传来的较大压应力扩散，使作用在基底的压应力满足地基承载力的设计要求。
2.1.12 无筋扩展基础 non-reinforced spread foundation
由砖、毛石、混凝土或毛石混凝土、灰土和三合土等材料组成的，且不需配置钢筋的墙下条形基础或柱下独立基础。
2.1.13 条形基础 strip foundation，strip footing
墙下或柱下的长条形基础。
2.1.14 筏形基础 raft foundation，mat foundation
支承整个结构物的荷载，且面积不小于建筑物底面积的钢筋混凝土平板或肋梁板基础。
2.1.15 桩基础 pile foundation
由设置于岩土中的桩和连接于桩顶端的承台组成的基础。
2.1.16 嵌岩桩 socketed pile
桩的下部有部分进入、支承于中风化、微风化岩层的桩。
2.1.17 支挡结构 retaining structure
使岩土边坡保持稳定、控制位移、主要承受侧向荷载而建造的结构物。
2.1.18 硬质岩石 hard rock
指饱和单轴抗压强度大于30MPa的岩石。
2.1.19 软质岩石 weak rock
指饱和单轴抗压强度小于或等于30MPa的岩石。
2.1.20 持力层 bearing layer，sustaining layer
直接承受基础荷载的地层。
2.1.21 压缩层 compressed layer
地基沉降计算深度范围内的土层总称。
2.1.22 下卧层 underlying layer
位于结构物基础持力层以下，并处于压缩层范围内的各土层。
2.1.23 冲剪破坏 punching failure
持力层在基础荷载作用下发生压缩变形及侧向挤压，使基础切入土中，产生连续下沉的地基破坏模式。
2.1.24 垫层 cushion
填筑于软弱地基土上或置换其上部的具有一定厚度的砂、碎石、灰土或素土层等。
2.1.25 岩石软化系数 softening coefficient of rock
岩石在饱和状态下的单轴抗压强度与在干燥状态下的单轴抗压强度的比值。
2.2 符 号
A——基础底面面积；
Ap——桩身截面面积；
a——压缩系数；
b——基础底面宽度(最小边长)或力矩作用方向的基础底面边长；
c——黏聚力；
ck——土的黏聚力标准值；
D——桩端扩底直径；
d——基础埋置深度，或桩身直径；
Ea——主动土压力；
Es——土的压缩模量；
E0——土的变形模量；
e——孔隙比；
F——基础顶面竖向力；
Fk——相应于荷载标准组合作用于基础顶面的竖向力；
fa——修正后的地基承载力特征值，或岩石地基承载力特征值；
fak——地基承载力特征值；
frk——岩石饱和单轴抗压强度标准值；
faz——软弱下卧层顶面处的地基承载力特征值；
G——恒载；
Gk——基础自重和基础上的土重标准值；
H0——基础高度；
Hf——自基础底面算起的建筑物高度；
Hg——自地面算起的建筑物高度；
L——房屋长度或沉降缝分隔的单元长度；
l——基础底面长度；
M——作用于基础底面的力矩或截面的弯矩设计值；
Mk——作用于基础底面的弯矩标准值或截面的弯矩标准值；
Mb、Md、Mc——承载力系数；
m——土的水平抗力系数的比例系数；
N——经过修正的标准贯入试验击数；
N′——实测的标准贯入试验击数；
N63.5——经过修正的重型动力触探试验击数；
——实测的重型动力触探试验击数；
n——桩数；
pk——相应于作用效应标准组合的基础底面处的平均压力；
p0——相应于作用效应标准组合的基础底面处平均附加压力；
pz——相应于作用效应标准组合时的基础底面处的附加应力；
pcz——软弱下卧层顶面处土的自重压力；
Qk——相应于作用效应标准组合竖向荷载、桩基中单桩所受竖向力；
qpa——桩端土的承载力特征值；
qsa——桩周土的摩擦力特征值；
Ra——单桩竖向承载力特征值；
RHa——单桩水平承载力特征值；
Rta——单桩抗拔承载力特征值；
St——土的灵敏度；
s——沉降量；
u——周边长度；
up——桩身周边长度；
W——基础底面的抵抗矩；
w——土的含水量；
wL——液限；
wp——塑限；
z——从基底荷载作用面算起的深度；
zn——地基沉降计算深度；
β——边坡对水平面的坡角；
γ——土的重力密度，简称土的重度；
γm——基础埋深范围内各土层的加权平均重度，地下水位以下取有效重度；
——内摩擦角；
δ——土与挡土墙墙背的摩擦角；
μ——土与挡土墙基底间的摩擦系数；
ηb——基础宽度的承载力修正系数；
ηd——基础埋深的承载力修正系数；
θ——地基的压力扩散角；
v——土的泊松比；
ψf——回归修正系数；
ψs——沉降计算经验系数；
、 ——基础底面计算点至第i层土、第i-1层土底面范围内平均附加应力系数。
3 基本规定
3.0.1 根据地基复杂程度、建筑物规模和特征以及由于地基基础问题可能对建筑物造成破坏或影响正常使用的程度，将地基基础设计分成三个等级，设计时应根据具体情况，按表3.0.1选用。
表3.0.1 地基基础设计等级
设计等级 建筑及地基类型
甲级 重要的工业与民用建筑；
30层以上的高层建筑；
体形复杂、层数相差超过10层的高低层连成一体建筑物；
大面积的多层地下建筑物(如地下车库、商场、运动场等)；
对地基变形控制有特殊要求的建筑物；
复杂地质条件下的坡上建筑物(包括高边坡)；
对邻近建筑物影响较大的新建建筑物；
场地和地基条件复杂的一般建筑物
乙级 除甲级、丙级以外的工业与民用建筑物
丙级 场地和地基条件简单、荷载分布均匀的七层及七层以下民用建筑及一般工业建筑；次要的轻型建筑物
3.0.2 根据建筑物地基基础设计等级及长期荷载作用下地基变形对上部结构的影响程度，地基基础设计应符合下列规定：
1 所有建筑物的地基计算均应满足承载力计算的有关规定。
2 设计等级为甲级、乙级建筑物应进行地基变形计算。
3 设计等级为丙级的建筑物有下列情况之一时应作变形验算：
1) 地基承载力特征值小于130kPa，且体形复杂的建筑。
2) 在基础上及其附近有地面堆载或相邻基础荷载差异较大，可能引起地基产生过大的不均匀沉降时。
3) 软弱地基上的建筑物存在偏心荷载时。
4) 相邻建筑物距离近，可能发生倾斜时。
5) 地基内有厚度较大或厚薄不均的填土，其自重固结未完成时。
4 对经常受水平荷载作用的高层建筑、高耸结构和挡土墙等，以及建造在斜坡上或边坡附近的建筑物和构筑物，尚应验算其稳定性。
5 基坑工程应进行稳定性验算。
6 建筑地下室或地下构筑物存在上浮问题时，尚应进行抗浮验算。
3.0.3 下列范围的建筑物可不做变形验算：
1 浅基础持力层为中、微风化岩；或十五层以下、基础为条形、筏形基础，持力层为地基承载力特征值≥300kPa的碎石土、密实砂、硬塑至坚硬残积土层或全风化、强风化岩层；桩基础、持力层为中微风化岩层；或三十层以下、桩基础持力层为中—密实砂层、卵、碎石层(且没有软弱下卧层)，硬塑至坚硬残积土、全风化、强风化岩层的建筑物。
2 表3.0.3所列范围内的丙级建筑物。
表3.0.3 可不作地基变形计算的设计等级为丙级建筑物范围
地基主要受力层情况 地基承载力特征值fak(kPa) 60≤fak＜80 80≤fak＜100 100≤fak＜130 130≤fak＜160 160≤fak＜200 200≤fak＜300
各土层坡度(％) ≤5 ≤5 ≤10 ≤10 ≤10 ≤10
建筑类型 砌体承重结构、框架结构(层数) ≤3 ≤5 ≤5 ≤6 ≤6 ≤7
单层排架结构(6m柱距) 单跨 吊车额定起重量(t) 5～10 10～15 15～20 20～30 30～50 50～100
厂房跨度(m) ≤12 ≤18 ≤24 ≤30 ≤30 ≤30
多跨 吊车额定起重量(t) 3～5 5～10 10～15 15～20 20～30 30～75
厂房跨度(m) ≤12 ≤18 ≤24 ≤30 ≤30 ≤30
烟囱 高度(m) ≤20 ≤40 ≤50 ≤75 ≤100
水塔 高度(m) ≤15 ≤20 ≤30 ≤30 ≤30
容积(m3) ≤50 50～100 100～200 200～300 300～500 500～1000
注：1 地基主要受力层系指条形基础底面下深度为3b(b为基础底面宽度)，独立基础下为1.5b，且厚度均不小于5m范围(二层以下的一般民用建筑除外)；
2 地基主要受力层中如有承载力特征fak值小于130kPa的土层时，表中砌体承重结构的设计，应符合本规范第7章的有关要求；
3 表中砌体承重结构和框架结构均指民用建筑，对于工业建筑可按厂房高度、荷载情况折合成与其相当的民用建筑层数；
4 表中吊车额定起重量、烟囱高度和水塔容积的数值系指最大值。
3.0.4 地基基础设计前必须进行岩土工程勘察，依据岩土工程勘察报告，结合上部结构的具体情况、建筑场址的环境和施工条件进行基础选型和设计。
3.0.5 地基基础设计时，所采用的作用效应最不利组合应按下列规定：
1 按地基承载力特征值确定基础底面积及埋深或按单桩承载力特征值确定桩数时，传至基础或承台底面上的作用效应应取正常使用极限状态下作用效应的标准组合，相应的抗力采用修正后的地基承载力特征值或单桩承载力特征值。
2 计算地基变形时，传至基础底面上的作用效应应取正常使用极限状态下作用效应的准永久组合，不应计入风荷载和地震作用。相应的限值应为地基变形允许值。
3 计算挡土墙土压力、地基或边坡稳定以及地下室抗浮稳定时，作用效应应取承载能力极限状态下的基本组合，分项系数均取1.0。
4 在进行基础结构构件的截面设计或验算时，上部结构传来的作用效应组合和相应的基底反力、作用于基础结构构件的水、土压力、滑坡推力等，应按承载能力极限状态下作用效应的基本组合，采用相应的分项系数。
当需要验算基础变形、裂缝宽度时，取正常使用极限状态作用效应的标准组合。
5 基础设计安全等级、结构设计使用年限、结构重要性系数应按有关规范的规定采用，但结构重要性系数γ0不应小于1.0。
3.0.6 正常使用极限状态下，作用效应的荷载组合应用下列公式表示：
1 由可变作用效应控制的标准组合值Sk应按下式计算：
Sk＝SGk＋SQ1k＋ψc2SQ2k＋……＋ψcnSQnk (3.0.6-1)
2 由永久作用效应控制的标准组合值Sk应按下式计算：
Sk＝SGk＋ψc1SQ1k＋ψc2SQ2k＋……＋ψcnSQnk (3.0.6-2)
式中：SGk——按永久作用标准值Gk计算的效应值；
SQik——按可变作用标准值Qik计算的效应值；
ψci——可变荷载Qi的组合值系数，按现行《建筑结构荷载规范》GB 50009的规定取值。
当考虑以永久作用效应控制的组合时，参与组合的可变作用仅限于竖向荷载。
3 作用效应的准永久组合值Sk应按下式计算：
Sk＝SGk＋ψq1SQ1k＋ψq2SQ2k＋……＋ψqnSQnk (3.0.6-3)
式中：ψqi——准永久值系数，按现行《建筑结构荷载规范》GB 50009的规定取值。
3.0.7 在进行基础结构构件的截面承载力计算或验算时，应按下列规定确定相应的作用效应基本组合设计值，取其不利者：
1 永久作用与竖向可变作用效应组合：
计算时已考虑组合值系数(即活荷载折减)，取
S＝1.35Sk (3.0.7-1)
计算时组合值系数取1(即不考虑活荷载折减)，取
S＝1.30Sk (3.0.7-2)
2 永久作用与可变作用(包括竖向荷载、风、地震作用等)效应组合，取
S＝1.25Sk (3.0.7-3)
并应满足 S≤R (3.0.7-4)
式中：R——基础结构构件抗力的设计值，按有关建筑结构设计规范的规定确定；
Sk——荷载效应的标准组合值。
3.0.8 基础的设计使用年限不应低于其上部结构的使用年限。基础混凝土结构的耐久性设计应符合现行国家标准《混凝土结构设计规范》GB 50010的规定。
3.0.9 地基基础在施工过程及完成后，应进行质量检验，必要时还应进行变形、受力监测。
4 岩土工程勘察
4.1 一般规定
4.1.1 进行建筑地基勘察前，应详细了解建筑设计意图，搜集和了解建筑场地及其邻近地段已有的勘察资料和工程经验，并取得由委托方提供的下列资料：
1 比例尺不小于1：2000的现状地形图及附有建筑红线资料、建筑物坐标和现状地形高程的拟建建筑物平面位置图。
2 拟建场地的地质成因及演化以及地下管线、地下构筑物等的分布情况和邻近水准基点的位置、高程、坐标等。
3 拟建建筑的平面布置、高度、层数、结构类型、荷载条件、有无地下室及尺寸和深度、可能采用的基础类型等情况。
4 搜集拟建场地区域的工程地质、水文地质和地震背景资料。
4.1.2 建筑地基勘察应符合下列要求：
1 查明建筑物范围内地层的结构、成因、年代、各岩土层的物理力学性质，并对地基的均匀性、承载力和变形特性做出评价。
2 查明不良地质作用及其分布范围、发展趋势、危害程度，提出治理方案建议；查明场地特殊岩土的性质及其分布。
3 查明地下水类型、埋藏条件、补给及排泄条件、腐蚀性、初见及稳定水位，提供季节变化幅度和各主要地层的渗透系数。
4 提出各岩土层的地基承载力特征值的建议值，提出经济合理、技术可靠的地基基础方案建议。
5 对复合地基或桩基类型、适宜性、持力层选择提出建议，提供桩的侧阻力特征值、端阻力特征值和变形计算的有关参数的建议值；对成桩可行性、施工时对环境的影响及桩基施工中应注意的问题提出意见。
6 提供计算变形所需的有关参数。
7 对场地的稳定性和地震效应进行评价。
8 岩石地基的勘察应查明岩石的地质年代、名称、风化程度及其空间分布特征，岩体结构面类型、性质、组合特征和发育程度，评价岩体基本质量等级，如存在断裂构造时，应评价断裂构造对工程的影响。
9 当工程需要时尚应解决下列问题：
1) 提供深基坑开挖的边坡稳定计算参数和支护方案的建议，论证基坑开挖对周围已有建(构)筑物、道路和地下管线以及地下设施的影响。
2) 提供基坑施工中地下水控制方案的建议，论证基坑施工降水对周围环境的影响。
3) 山区地基的边坡，当进行开挖时，提供边坡开挖的允许坡率建议。
4.1.3 勘察报告的内容和编制应符合国家现行有关岩土工程勘察规范的规定，并应达到相应勘察阶段编制深度的要求。
4.1.4 基础施工时发现地质条件变化较大，与原勘察报告不一致并影响设计和施工，或地基出现异常情况时，应及时进行补充勘察。
4.2 岩土的分类
4.2.1 建筑地基的岩土可分为岩石、天然土和人工填土；天然土按地质成因可分为海积土、冲积土、洪积土、湖积土、坡积土和残积土等，按颗粒级配或塑性指数可分为碎石土、砂土、粉土和黏性土；人工填土按其组成可分为素填土、杂填土、吹填土、压实填土和填石等。
4.2.2 岩石按成因分为岩浆岩、沉积岩和变质岩。本地区这三类成因的代表性岩见表4.2.2。
表4.2.2 岩石按成因的划分
成因类别 代表性岩石
岩浆岩 花岗岩、闪长岩、花岗斑岩、安山岩、玄武岩、辉绿岩、流纹岩、火山凝灰岩等
沉积岩 灰岩、白云岩、砾岩、砂岩、泥岩(黏土岩)、页岩等
变质岩 片麻岩、千枚岩、大理岩、片岩等
4.2.3 岩石的坚硬程度可根据岩样的饱和单轴抗压强度标准值frk按表4.2.3-1分为坚硬岩、较硬岩、较软岩、软岩和极软岩。当缺乏饱和单轴抗压强度资料或不能进行该项试验时，可在现场按表4.2.3-2的规定进行定性划分。
表4.2.3-1 岩石坚硬程度的划分
坚硬程度类别 饱和单轴抗压强度标准值frk(MPa) 代表性岩石
坚硬岩 ＞60 花岗岩、闪长岩、玄武岩、石灰岩、硅质或铁质胶结的砾岩、花岗片麻岩、大理岩
较硬岩 30＜frk≤60
较软岩 15＜frk≤30 砾岩、砂岩、泥质砾岩、泥质砂岩、泥灰岩、泥质粉砂岩、粉砂质泥岩、泥岩、页岩、千枚岩、云母片岩
软岩 5＜frk≤15
极软岩 ≤5
表4.2.3-2 岩石坚硬程度的定性划分
名称 定性鉴定 代表性岩石
硬质岩 坚硬岩 锤击声清脆，有回弹，震手，难击碎；
基本无吸水反应 新鲜—微风化的花岗岩、闪长岩、辉绿岩、玄武岩、安山岩、片麻岩、石英岩、硅质砾岩、石英砂岩、硅质灰岩等
较硬岩 锤击声较清脆，有轻微回弹，稍震手，较难击碎；
有轻微吸水反应 1.微风化的坚硬岩；
2.未风化—微风化的大理岩、板岩、石灰岩、钙质砂岩等
软质岩 较软岩 锤击声不清脆，无回弹，较易击碎；
指甲可刻出印痕 1.中风化的坚硬岩和较硬岩；
2.未风化—微风化的凝灰岩、千枚岩、砂质泥岩、泥灰岩等
软岩 锤击声哑，无回弹，有凹痕，易击碎；
浸水后，易崩解 1.强风化的坚硬岩和较硬岩；
2.中风化的较软岩；
3.未风化—微风化的泥质砂岩、泥岩等
极软岩 锤击声哑，无回弹，有较深凹痕，手可捏碎；
浸水后，可捏成团 1.风化的软岩；
2.全风化的各种岩石；
3.各种半成岩
4.2.4 岩石的风化程度可分为未风化、微风化、中风化、强风化和全风化。岩石风化程度分类见表4.2.4。
表4.2.4 岩石风化程度的划分
风化程度 特征
未风化 岩质新鲜，偶见风化迹象
微风化 结构和构造基本未变，仅节理面有铁锰质渲染或矿物略有变色。有少量风化裂隙
中风化 1.组织结构部分破坏，矿物成分基本未变，沿节理面出现次生矿物，风化裂隙发育；
2.岩体被节理、裂隙分割成块状(200mm～500mm)，硬质岩，锤击声脆，且不易击碎；软质岩锤击易碎；
3.用镐难挖掘，用岩芯钻方可钻进
强风化 1.组织结构已大部分破坏，矿物成分已显著变化；
2.岩体被节理、裂隙分割成碎石状(20mm～200mm)，碎石用手可以折断；
3.用镐可以挖掘，用干钻不易钻进
全风化 1.结构已基本破坏，但尚可辨认；
2.岩石已风化成坚硬或密实土状，可用镐挖，干钻可钻进；
3.须机械普遍刨松方能铲挖满载
残积土 组织结构全部破坏，已风化成土状，锹镐易挖掘，干钻易钻进，具可塑性
注：1 花岗岩类的岩石风化岩，可采用实测标准贯入击数N′划分，N′≥70为强风化；70＞N′≥40为全风化；N′＜40为残积土。其他岩石的风化岩，可采用实测标准贯入击数N′划分，N′≥50为强风化；50＞N′≥30为全风化；N′＜30为残积土。
2 泥岩和半成岩，可不进行风化程度划分。
4.2.5 岩体完整程度宜按表4.2.5划分为完整、较完整、较破碎、破碎和极破碎。
表4.2.5 岩体完整程度划分
名称 控制性结构面平均间距(m) 完整性指数 相应结构类型
完整
较完整
较破碎
破碎
极破碎 ＞1.0
0.4～1.0
0.2～0.4
＜0.2
无序 ＞0.75
0.75～0.55
0.55～0.35
0.35～0.15
＜0.15 整体状或巨厚层状结构
块状或厚层状结构
裂隙块状、镶嵌状、中薄层状结构
破碎状结构、页状结构
散体状结构
注：完整性指数为岩体纵波波速与岩块纵波波速之比的平方。选定岩体、岩块测定波速时应注意其代表性。
4.2.6 岩体基本质量等级可根据岩石的坚硬程度和岩体的完整程度按表4.2.6进行分类。
表4.2.6 岩体基本质量等级分类
完整程度
坚硬程度 完整 较完整 较破碎 破碎 极破碎
坚硬岩 Ⅰ Ⅱ Ⅲ Ⅳ Ⅴ
较硬岩 Ⅱ Ⅲ Ⅳ Ⅳ Ⅴ
较软岩 Ⅲ Ⅳ Ⅳ Ⅴ Ⅴ
软岩 Ⅳ Ⅳ Ⅴ Ⅴ Ⅴ
极软岩 Ⅴ Ⅴ Ⅴ Ⅴ Ⅴ
4.2.7 岩石的描述应包括地质年代、地质名称、风化程度、颜色、主要矿物、结构、构造和岩石质量指标(RQD)。对沉积岩应着重描述沉积物的颗粒大小、形状、胶结物成分和胶结程度；对岩浆岩和变质岩应着重描述矿物结晶大小和结晶程度。岩体的描述应包括结构面、结构体、岩层厚度和结构类型。描述要求应符合现行国家标准《岩土工程勘察规范》GB 50021的规定。
4.2.8 软质岩石可分为软化类岩石和不软化类岩石，软化类岩石的软化系数不大于0.75；当软化系数大于0.75时，应定为不软化岩。
4.2.9 碎石土应为粒径大于2mm的颗粒超过全重50％的土。碎石土可按表4.2.9分为漂石、块石、卵石、碎石、圆砾和角砾。
表4.2.9 碎石土的分类
土的名称 颗粒形状 粒组含量
漂石
块石 圆形及亚圆形为主
棱角形为主 粒径大于200mm的颗粒含量超过全重50％
卵石
碎石 圆形及亚圆形为主
棱角形为主 粒径大于20mm的颗粒含量超过全重50％
圆砾
角砾 圆形及亚圆形为主
棱角形为主 粒径大于2mm的颗粒含量超过全重50％
注：分类时应根据粒组含量栏从上到下以最先符合者确定。
4.2.10 碎石土的密实度，可按表4.2.10分为松散、稍密、中密、密实。
表4.2.10 碎石土的密实度
修正后的重型圆锥动力触探试验锤击数N63.5 密实度
N63.5≤5 松散
5＜N63.5≤10 稍密
10＜N63.5≤20 中密
N63.5＞20 密实
注：本表适用于平均粒径小于等于50mm且最大粒径不超过100mm的卵石、碎石、圆砾、角砾。对平均粒径大于50mm或最大粒径大于100mm的碎石土，可按国家标准GB 50007附录B鉴别其密实度。
4.2.11 砂土为粒径大于2mm的颗粒含量不超过全重50％、粒径大于0.075mm的颗粒含量超过全重50％的土。砂土可按表4.2.11分为砾砂、粗砂、中砂、细砂和粉砂。
表4.2.11 砂土的分类
土的名称 粒组含量
砾砂 粒径大于2mm的颗粒含量占全重25％～50％
粗砂 粒径大于0.5mm的颗粒含量超过全重50％
中砂 粒径大于0.25mm的颗粒含量超过全重50％
细砂 粒径大于0.075mm的颗粒含量超过全重85％
粉砂 粒径大于0.075mm的颗粒含量超过全重50％
注：分类时应根据粒组含量栏从上到下以最先符合者确定。
4.2.12 砂土的密实度，可按表4.2.12-1分为松散、稍密、中密和密实；也可根据修正后的重型圆锥动力触探击数按表4.2.12-2分类。
表4.2.12-1 砂土的密实度分类
实测标准贯入试验锤击数N′ 密实度
N′≤10 松散
10＜N′≤15 稍密
15＜N′≤30 中密
N′＞30 密实
表4.2.12-2 砂土的密实度分类
修正后的重型圆锥动力触探锤击数N63.5 密实度
N63.5≤4 松散
4＜N63.5≤6 稍密
6＜N63.5≤9 中密
N63.5＞9 密实
4.2.13 黏性土为塑性指数Ip大于10的土，可按表4.2.13分为黏土、粉质黏土。
表4.2.13 黏性土的分类
塑性指数Ip 土的名称
Ip＞17 黏土
10＜Ip≤17 粉质黏土
注：塑性指数由相应于76g圆锥体沉入土样中深度为10mm时测定的液限计算而得。
4.2.14 黏性土的状态，可按表4.2.14-1分为坚硬、硬塑、可塑、软塑、流塑；也可根据原位实测标贯击数和修正后的重型圆锥动力触探击数按表4.2.14-2和表4.2.14-3分类。
表4.2.14-1 黏性土的状态
液性指数IL 状态
IL≤0 坚硬
0＜IL≤0.25 硬塑
0.25＜IL≤0.75 可塑
0.75＜IL≤1 软塑
IL＞1 流塑
表4.2.14-2 黏性土的状态
实测标准贯入试验锤击数N′ 状态
N′≤3 流塑
3＜N′≤5 软塑
5＜N′≤10 软可塑
10＜N′≤15 硬可塑
15＜N′≤20 硬塑
N′＞20 坚硬
表4.2.14-3 黏性土的状态
修正后的重型圆锥动力触探锤击数N63.5 状态
N63.5≤1.5 流塑
1.5＜N63.5≤3 软塑
3＜N63.5≤7.5 可塑
7.5＜N63.5≤10 硬塑
N63.5＞10 坚硬
4.2.15 粉土为介于砂土和黏性土之间，塑性指数Ip≤10且粒径大于0.075mm的颗粒含量不超过全重50％的土。
4.2.16 粉土的密实度可按表4.2.16分为松散、稍密、中密、密实。
表4.2.16 粉土的密实度
实测标准贯入试验锤击数N′ 密实度
N′≤5 松散
5＜N′≤10 稍密
10＜N′≤15 中密
N′＞15 密实
4.2.17 土的压缩性分类可按照压缩模量的大小进行并应符合表4.2.17的规定。
表4.2.17 土的压缩性分类
压缩模量Es(MPa) 压缩性
Es≤5 高压缩性
5＜Es≤10 中高压缩性
10＜Es≤15 中低压缩性
Es＞15 低压缩性
注：进行压缩性评价时，压缩模量Es取自重压力至自重压力与附加压力之和的压力段计算。
4.2.18 软土包括淤泥、淤泥质土和有机质土等饱和软黏土。淤泥为在静水或缓慢的流水环境中沉积，并经生物化学作用形成，其天然含水量大于液限、天然孔隙比大于或等于1.5的黏性土。当天然含水量大于液限而天然孔隙比小于1.5但大于或等于1.0的黏性土或粉土应为淤泥质土。当土体中有机质含量大于5％且小于或等于10％的土为有机质土，有机质含量大于10％且小于或等于60％的土为泥炭质土，有机质含量大于60％的土为泥炭。
4.2.19 红黏土为碳酸盐岩系的岩石经红土化作用形成的高塑性黏土。其液限一般大于50％。红黏土经再搬运后仍保留其基本特征，液限大于或等于45％但小于50％的土为次生红黏土。
4.2.20 膨胀土为土中黏粒成分主要由亲水性矿物组成，同时具有显著的吸水膨胀和失水收缩特性，其自由膨胀率(δef)大于或等于40％时的黏性土。
膨胀土地区的工程建设，应按照国家标准《膨胀土地区建筑技术规范》GBJ 112的规定，根据膨胀土的特性、地基的胀缩等级和工程要求进行设计、施工和维护管理。
4.2.21 花岗岩残积土为未经搬运的花岗岩全风化产物，扰动后遇水易崩解。
花岗岩残积土中，当大于2mm颗粒含量超过总质量20％者为砾质黏性土，不超过20％者为砂质黏性土，不含者为黏性土。
4.2.22 污染土是由于致污物质的侵入改变了物理力学性状的土。
4.2.23 人工填土指人类活动而堆积的土，根据其组成和成因，可分为素填土、杂填土、冲填土和压实填土。
素填土为由碎石土、砂土、粉土、黏性土等一种或几种组成的填土。经过压实或夯实的素填土为压实填土。杂填土为含有建筑垃圾、工业废料、生活垃圾等杂物的填土。冲填土为由水力冲填泥砂形成的填土。