标准编号:	GB 50007-2011
中文名称:	建筑地基基础设计规范
英文名称:	Code for design of building foundation
行业分类:	GB    国家标准
发布机构:	中华人民共和国住房和城乡建设部
发布日期:	2011-07-26
实施日期:	2012-8-1
标准状态:	现行
替代旧标准:	GB 50007-2002 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:	46000 字
翻译价格(元):	290.00 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.

According to the requirements of Document Jian Biao [2008] No. 102 issued by the Ministry of Housing and Urban-Rural Development-"Notice on Printing and Publishing the Development and Revision Plan of National Engineering Construction Standards in 2008 (first batch)", this code is revised from the former "Code for Design of Building Foundation" GB 50007-2002 by China Academy of Building Research jointly with all the organizations concerned.

During the preparation process, the drafting group finally finalized this code upon review based on extensive investigation and study, earnestly summarizing the practical experience, making reference to the foreign advanced standards, coordinating with relevant national standards and extensively soliciting for opinions.

This code comprises 10 chapters and 22 appendixes, with main technical content including general provisions, terms and symbols, basic requirements, geotechnical classification and index properties, foundation design calculation, foundation in mountain area, soft ground, foundation type, excavation engineering, inspection and monitoring.

The main technical contents revised in this code are:

1. Add the relevant content of excavation engineering in the design grade of foundation;

2. The design working life of foundation shall not be less than that of building structure;

3. Add the engineering definitions of peat and cumulosol;

4. Add resilience recompression deformation calculation method;

5. Add building anti-floating stability calculation method;

6. Add the design principles of soil-rock composite ground with rock face gradient greater than 10% and foundation soil thickness greater than 1.5m when the medium and underlying rock face is inclining in single direction;

7. Add the design content of rock foundation;

8. Add the principle of design of foundation for the site in karst region according to the karst development degree;

9. Add the calculation method for composite ground deformation;

10. Add the design requirements that the minimum ratio of reinforcement of spread foundation shall not be less than 0.15%;

11. Add the requirements for the shear bearing capacity calculation of oblique section when the short-side dimension of the spread foundation bottom is less than or equal to the column width plus 2 times the foundation effective height;

12. Adjust the settlement empirical coefficient through statistical analysis for pile foundation settlement calculation method;

13. Add the requirements that the excavation engineering featured by complex hydrogeologic conditions on site, high protection requirement for surrounding environment of foundation pit and Grade-A design grade shall be subjected to special design for underground water control in high underground water level area;

14. Add the engineering inspection requirements for ground treatment engineering;

15. Add the key points for horizontal loading test of single pile and key points for vertical pullout load testing of single pile.

In this code, the provisions printed in bold type are compulsory ones and must be enforced strictly.

The Ministry of Housing and Urban-Rural Development is in charge of the administration of this code and the explanation of the compulsory provisions; the China Academy of Building Research is responsible for the explanation of specific technical contents. During the process of implementing this code, the relevant opinions or advice, whenever necessary, can be posted or passed on to the national standard "Code for Design of Building Foundation" Administrative Group of China Academy of Building Research (address: No. 30, North Third Ring East Road, Beijing, 100013, China, Email: tyjcabr@sina.com.cn).

Chief development organization of this code: China Academy of Building Research

Participating development organizations of this code: CIGIS

Beijing Geotechnical Institute

China Southwest Geotechnical Investigation and Architecture Design Institute

Guiyang Architectural Design & Surveying Prospecting Co., Ltd.

Beijing Institute of Architectural Design

China Architecture Design and Research Group

Shanghai Xiandai Architectural Design Group Co., Ltd.

China Northeast Architectural Design & Research Institute

Liaoning Provincial Building Design & Research Institute

Yunnan Yicheng Architectural Design Company

Central-South Architectural Design Institute

Hubei Provincial Academy of Building Research

Guangzhou Academy of Building Research

Heilongjian Province Academy of Cold Area Building Research

Heilongjiang Province Building Engineering Quality Supervision Station

Northern Engineering & Technology Corporation, MCC

China State Construction Engineering Corp.

Tianjin University

Tongji University

Taiyuan University of Technology

Guangzhou University

Zhengzhou University

Southeast University

Chongqing University

Chief drafting staff of this code: Teng Yanjing, Huang Xiling, Wang Shuguang, Gong Jianfei, Wang Weidong, Wang Xiaonan, Wang Gongshan, Bai Xiaohong, Ren Qingying, Liu Songyu, Zhu Lei, Shen Xiaoke, Zhang Bingji, Zhang Chengjin, Zhang Jichao, Chen Xiangfu, Yang Min, Lin Liyan, Zheng Gang, Zhou Tonghe, Wei Wu, Hao Jiangnan, Hou Guangyu, Hu Daiwen, Yuan Neizhen, Gu Baohe, Tang Mengxiong, Gu Xiaolu, Liang Zhirong, Kang Jingwen, Pei Jie, Pan Kaiyun, Xue Huili

Chief examiners of this code: Xu Zhengzhong, Huang Shaoming, Wu Xuemin, Gu Guorong, Hua Jianxin, Wang Changqing, Xiao Ziqiang, Song Zhaohuang, Xu Tianping, Xu Zhangjian, Mei Quanting, Huang Zhihong, Dou Nanhua



Contents



1 General Provisions 1

2 Terms and Symbols 1

2.1 Terms 1

2.2 Symbols 2

3 Basic Requirements 3

4 Geotechnical Classification and Index Properties 8

4.1 Geotechnical Classification 8

4.2 Engineering Index Properties 11

5 Foundation Design Calculation 12

5.1 Embedded Depth of Foundation 12

5.2 Bearing Capacity Calculation 15

5.3 Deformation Calculation 19

5.4 Stability Calculation 24

6 Foundation in Mountain Area 26

6.1 General Requirements 26

6.2 Foundation on Rock and Soil 26

6.3 Foundation on Compacted Fill 28

6.4 Landslide Prevention 30

6.5 Foundation on Rock 32

6.6 Karst and Sinkhole 32

6.7 Earth Slope and Gravity Retaining Wall 35

6.8 Rock Slope and Anchor Wall 40

7 Soft Ground 42

7.1 General Requirements 42

7.2 Usage and Treatment 43

7.3 Architectural Measurement 45

7.4 Structural Measurement 46

7.5 Massive Ground Surcharge 47

8 Foundation 49

8.1 Non-reinforced Spread Foundation 49

8.2 Spread Foundation 50

8.3 Strip Foundation under Columns 60

8.4 Raft Foundation of High-rise Buildings 61

8.5 Pile Foundation 71

8.6 Rock Bolt Foundation 84

9 Excavation Engineering 85

9.1 General Requirements 85

9.2 Excavation Engineering Exploration and Environmental Investigation 87

9.3 Earth Pressure and Water Pressure 88

9.4 Design Calculation 89

9.5 Internal Bracing of Support Structure 90

9.6 Soil Bolt 91

9.7 Excavation Engineering Inverse Practice 92

9.8 Excavation Engineering of Rock Mass 94

9.9 Underground Water Control 94

10 Inspection and Monitoring 96

10.1 General Requirements 96

10.2 Inspection 96

10.3 Monitoring 99

Appendix A Division of Rock Hardness and Rock Mass Integrity Degree 101

Appendix B Field Identification of Gravel Soil 102

Appendix C Key Points for Shallow Plate Load Testing 103

Appendix D Key Points for Deep Plate Load Testing 104

Appendix E Standardized Value for Shear Strength Parameters C and 105

Appendix F Contour of Seasonal Standardized Frost Depth in China 107

Appendix G Classification of Soil Expansion upon Freezing and Maximum Allowable Thickness of Frozen Earth above Building Foundation 108

Appendix H Key Points for Loading Test on Rock 111

Appendix J Requirements for Uni-axial Compressive Strength Testing on Rock 113

Appendix K Stress Influence Coefficient α and Average Stress Influence Coefficient 114

Appendix L Active Earth Pressure Coefficient ka for Retaining Wall 128

Appendix M Key Points for Pullout Resistance Testing on Rock Anchors 134

Appendix N Calculation of Subsequent Foundation Settlement under Massive Ground Surcharge 135

Appendix P Perimeter of Critical Section for Shearing and Polar Moment of Inertia Calculation 137

Appendix Q Key Points for Vertical Static Load Test on Single Pile 140

Appendix R Final Settlement Calculation for Pile Foundation 142

Appendix S Key Points for Lateral Load Test on Single Pile 147

Appendix T Key Points for Uplift Capacity Test on Single Pile 151

Appendix U Anti-shearing Sectional Width of Step and Cone-shape Pile Cap 154

Appendix V Stability Evaluation for Excavation Support Structures 156

Appendix W Anti-seepage Stability Evaluation for Foundation Pit 160

Appendix Y Key Points for Pre-stressed Earth Anchor Testing 161

Explanation of Wording in this Code 163

List of Quoted Standards 164





1 General Provisions



1.0.1 This code is formulated with a view to implementing technical and economic policies of the nation in foundation design, and achieving safety and usability, advanced technology, economy and rationality, quality guarantee and environmental protection.

1.0.2 This code is applicable to the design of foundation of industrial and civil buildings (including structures). The design of collapsible loess, permafrost and expansive soil foundation and the foundation under the action of seismic and mechanical vibration load shall also meet the requirements of the current corresponding professional standard of the nation.

1.0.3 The design of foundation shall persist in the principle of adjusting measures to local conditions, using local materials, protecting environment and saving resources, comprehensively consider such factors as structure type, material condition and construction condition according to geotechnical engineering investigation data, and elaborately conduct.

1.0.4 The design of building foundation shall not only comply with this code, but also those in the current relevant ones of the nation.



2 Terms and Symbols



2.1 Terms



2.1.1 Ground, foundation soils

Soil mass or rock mass which supports foundation.

2.1.2 Foundation

Structure component which transfers various actions borne by the structure to the ground.

2.1.3 Characteristic value of subsoil bearing capacity

Pressure value corresponding to deformation specified within linear deformation section of subsoil pressure deformation curve determined by load test, and its maximum value is the proportion limit value.

2.1.4 Gravity density, unit weight

Gravity borne by rock-soil mass per unit volume, the product of density and gravity acceleration of rock-soil mass.

2.1.5 Rock discontinuity structural plane

Plane which cracks and is easy to crack in rock mass, such as bedding surface, joint, fault, schistosity, etc., also called discontinuous structural plane.

2.1.6 Standard frost penetration

Average value of maximum frost penetration actually measured for more than 10 years in the flat and exposed open area outside the city.

2.1.7 Allowable subsoil deformation

Deformation control value determined in order to guarantee normal use of the building.

2.1.8 Soil-rock composite ground

Ground with larger underlying bed rock surface gradient within the range of main bearing layer of building ground; or ground with densely-spread and exposed clint; or ground with exposed mass boulder or individual clint.

2.1.9 Ground treatment, ground improvement

Engineering measures to be taken in order to increase subsoil bearing capacity or improve its deformability or permeability.

2.1.10 Composite ground, composite foundation

Artificial ground that subsoil and reinforcement formed by reinforcing or replacing partial soil mass jointly bear load.

2.1.11 Spread foundation

Foundation that spreads a certain base area to side edge in order to diffuse the load transmitted from superstructure to make the compressive stress acted on the base meet the design requirements of subsoil bearing capacity and the internal stress of foundation meet the design requirements of material strength.

2.1.12 Non-reinforced spread foundation

Strip foundation under wall or independent foundation under column, composed of such materials as brick, rubble, concrete or rubble concrete, dirt and cement and not reinforced.

2.1.13 Pile foundation

Foundation which is composed of pile arranged in rock-soil and slab connected to pile top end.

2.1.14 Retaining structure

Structure which is built to make rock-soil side slope remain stable, control displacement and mainly bear lateral load.

2.1.15 Excavation engineering

General term of retaining structure, underground water control, environmental protection and other measures required for guaranteeing underground space formed in downward ground excavation safe and stable during the construction period of underground structure.



2.2 Symbols



2.2.1 Action and action effect

Ea——Active earth pressure;

Fk——Value of vertical force, transferred from superstructure to foundation top, corresponding to the acting standard combination;

Gk——Deadweight of foundation and soil weight on foundation;

Mk——Value of moment acts on the foundation bottom, corresponding to the acting standard combination;

pk——Average pressure at foundation bottom, corresponding to the acting standard combination;

p0——Average additional pressure at foundation bottom;

Qk——Vertical force borne by single pile in pile foundation under the action of axial vertical force, corresponding to the acting standard combination.

2.2.2 Resistance and material property

a——Compressibility coefficient;

c——Cohesion strength;

Es——Compression modulus of soil;

e——Void ratio;

fa——Corrected characteristic value of subsoil bearing capacity;

fak——Characteristic value of subsoil bearing capacity;

frk——Standardized value of uni-axial compressive strength of saturated rock;

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

qsa——Characteristic value of frictional force of pile periphery soil;

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

w——Moisture content of soil;

wL——Liquid limit;

wp——Plastic limit;

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

δ——Friction angle between fill and retaining wall back;

δr——Friction angle between fill and resistant rock slope surface;

θ——Pressure diffusion angle of ground;

μ——Friction coefficient between soil and retaining wall base;

v——Poisson's ratio;

φ——Internal friction angle.

2.2.3 Geometric parameters

A——Foundation bottom area;

b——Foundation bottom width (minimum side length); or foundation bottom side length of moment action direction;

d——Embedded depth of foundation, pile body diameter;

h0——Foundation height;

Hf——Building height counting from foundation bottom;

Hg——Building height counting from outdoor ground;

L——Building length or unit length separated by settlement joint;

l——Length of foundation bottom;

s——Settlement volume;

u——Peripheral length;

z0——Standard frost penetration;

zn——Calculation depth of ground settlement;

β——Slope angle of side slope to horizontal plane.

2.2.4 Calculation coefficient

——Average additional stress coefficient;

ηb——Correction coefficient of bearing capacity of foundation width;

ηd——Correction coefficient of bearing capacity of embedded depth of foundation;

φs——Empirical coefficient of settlement calculation.



3 Basic Requirements



3.0.1 The design of foundation shall be divided into three design grades according to ground complexity, building scale and functional characteristics as well as the degree of building damage or normal use influence caused by possible ground problems, and shall be selected in accordance with those specified in Table 3.0.1 according to specific conditions.

Table 3.0.1 Design Grade of Foundation

Design grade Building and ground type

Grade A Important industrial and civil buildings

High-rise buildings with more than 30 storeys

Combined high- and low-storey building with complicated shape and storey number difference exceeding 10

Extensive multi-story underground building (such as underground garage, shopping mall and sports ground)

Building with specific requirements for subsoil deformation

Building on slope (including high slope) under complicated geological conditions

Newly-built building with larger influence on existing engineering

General building with complicated site and ground conditions

Excavation engineering of basement of two-storey or above building in complicated geological conditions and soft soil area

Excavation engineering with excavation depth greater than 15m

Excavation engineering with complicated surrounding environment condition and high environmental protection requirements

Grade B Industrial and civil buildings beyond Grade A and Grade C

Excavation engineering beyond Grade A and Grade C

Grade C Seven-storey or below civil buildings and general industrial buildings with simple site and ground conditions and even load distribution; secondary light buildings

Excavation engineering in non-soft soil area, with simple site geological conditions, simple foundation pit surrounding environment conditions, not high environmental protection requirements and excavation depth less than 5.0m

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

1 The foundation design calculation of all the buildings shall meet the relevant requirements for calculation of bearing capacity;

2 The buildings with a design grade of Grade A or Grade B shall be designed according to subsoil deformation;

3 The buildings with a design grade of Grade C shall be subjected to deformation checking under one of the following conditions:

1) Buildings with characteristic value of subsoil bearing capacity less than 130kPa and with complicated shape;

2) When there is ground loading on the foundation and neighborhood or the difference between the adjacent loads is large, and the ground may be caused to generate excessive nonuniform settlement;

3) When the building on soft ground has eccentric load;

4) When the adjacent buildings are close and may have inclination;

5) When there is relatively thick or uneven fill in ground and the deadweight consolidation is not completed.

4 For high-rise buildings, high-rise structure, retaining wall, etc. frequently subjected to horizontal load, as well as buildings and structures built on slope or near side slope, their stability shall also be checked;

5 Excavation engineering shall be subjected to stability checking;

6 When building basement or underground structure has floating upward problem, anti-floating checking shall also be conducted.

3.0.3 The buildings with a design grade of Grade C within the range listed in Table 3.0.3 may not be subjected to deformation checking.

Table 3.0.3 Range of Buildings with a Design Grade of Grade C not Subjected to Subsoil Deformation Checking

Conditions of main bearing layer of ground Characteristic value of subsoil bearing capacity

fak(kPa) 80≤fak<100 100≤fak<130 130≤fak<160 160≤fak<200 200≤fak<300

Gradient of each soil layer (%) ≤5 ≤10 ≤10 ≤10 ≤10

Building type Masonry bearing structure and frame structure

(layer number) ≤5 ≤5 ≤6 ≤6 ≤7

Single-layer bent structure (6m column space) Single-span Rated lifting capacity of crane (t) 10~15 15~20 20~30 30~50 50~100

Plant building span

(m) ≤18 ≤24 ≤30 ≤30 ≤30

Multi-span Rated lifting capacity of crane (t) 5~10 10~15 15~20 20~30 30~75

Plant building span

(m) ≤18 ≤24 ≤30 ≤30 ≤30

Chimney Height (m) ≤40 ≤50 ≤75 ≤100

Water tower Height (m) ≤20 ≤30 ≤30 ≤30

Volume (m3) 50~100 100~200 200~300 300~500 500~1000

Notes: 1 The main bearing layer of ground refers to the range with a depth of 3b (b is the foundation bottom width) under strip foundation bottom, 1.5b under independent foundation, and thickness not less than 5m (except the general civil buildings less than two storeys);

2 If the main bearing layer of ground has soil layer with characteristic value of bearing capacity less than 130kPa, the design of masonry bearing structure in this table shall meet the relevant requirements of Chapter 7 of this code;

3 Masonry bearing structure and frame structure in this table refer to civil buildings; for industrial buildings, equivalent storey number of civil buildings may be converted according to plant building height and load condition;

4 The value of rated lifting capacity of crane, chimney height and water tower volume in this table refers to the maximum value.

3.0.4 Geotechnical engineering investigation shall be carried out before the design of foundation and shall meet the following requirements:

1 Geotechnical engineering investigation report shall be provided with the following data:

1) Check whether there is adverse geologic action influencing building site stability and assess the hazard degree;

2) Stratum structure and its uniformity within building range, physical and mechanical property indexes of each rock-soil layer as well as corrosiveness for building materials;

3) Underground water embedment condition, type, water-level fluctuation amplitude and rule, as well as corrosiveness for building materials;

4) Classify site category in seismic fortification zone, and carry out liquification evaluation for saturated sandy soil and silty soil;

5) Demonstrate and analyze the available design scheme of foundation, and propose economic and rational and advanced-technology design scheme suggestion; provide subsoil bearing capacity and deformation calculation parameters corresponding to the design requirements, and propose suggestion for problems to be noticed in design and construction;

6) If necessary for engineering, provide: rock-soil technical parameters required for slope stability calculation and support design of deep foundation pit excavation, demonstrate the influence on surrounding environment; technical parameters related to precipitation in foundation pit construction and suggestion for underground water control method; fortification water level for calculating underground water flotage.

2 The ground assessment should adopt boring sampling, laboratory soil test, penetration test and combine other in-situ test methods. For the buildings with a design grade of Grade A, load test index, shear strength index, deformation parameter index and penetration test data shall be provided; for the buildings of Grade B, shear strength index, deformation parameter index and penetration test data shall be provided; for the buildings of Grade C, penetration test and necessary boring and soil test data shall be provided.

3 All the building grounds shall be subjected to construction and foundation subsoil inspection. Where the ground condition doesn't conform to the original investigation report, construction investigation shall be carried out.

3.0.5 In design of foundation, the adopted action effect and corresponding resistance limit value shall meet the following requirements:

1 When determining foundation bottom area and buried depth according to subsoil bearing capacity or determining pile number according to single pile bearing capacity, the action effect transmitted to foundation or slab bottom shall be in accordance with the standard combination acting in limit state of normal use, and the corresponding resistance shall adopt characteristic value of subsoil bearing capacity or characteristic value of single pile bearing capacity;

2 When calculating subsoil deformation, the action effect transmitted to foundation bottom shall be in accordance with the quasi-permanent combination acting in limit state of normal use and shall not be counted into wind load and earthquake action; corresponding limit value shall be the allowable subsoil deformation;

3 When calculating retaining wall, ground or landslide stability and foundation anti-floating stability, the action effect shall be in accordance with the fundamental combination acting in limit state of bearing capacity, but the partial coefficient shall be 1.0;

4 When determining foundation or pile foundation slab height, retaining structure section, calculating internal force of foundation or retaining structure, determining reinforcement and checking material strength, the action effect transmitted from superstructure and corresponding base counterforce, retaining wall earth pressure and landslide thrust shall be in accordance with the fundamental combination acting in limit state of bearing capacity, and the corresponding partial coefficient shall be adopted; if it is necessary to check the foundation crack width, they shall be in accordance with the standard combination acting in limit state of normal use;

5 Foundation design safety class, structure design service life and significance coefficient of structure shall be adopted according to the relevant specifications, but the significance coefficient of structure Υ0 shall not be less than 1.0.

3.0.6 In the design of foundation, the design value of the action combination effect shall meet the following requirements:

1 In limit state of normal use, the design value of the standard combination effect Sk shall be determined according to the following formula:

Sk=SGk+SQ1k+ψc2SQ2k+……+ψcnSQnk (3.0.6-1)

Where,

SGk——the effect of standardized value of permanent action Gk;

SQik——the effect of standardized value of the ith variable action Qik;

ψci——the combination value coefficient of the ith variable action Qi, valued according to the requirements of the current national standard "Load Code for the Design of Building Structures" GB 50009.

2 The design value of the quasi-permanent combination effect Sk shall be determined according to the following formula:

Sk=SGk+ψq1SQlk+ψq2SQ2k+……+ψqnSQnk (3.0.6-2)

Where,

ψqi——the quasi-permanent value coefficient of the ith variable action Qi, valued according to the requirements of the current national standard "Load Code for the Design of Building Structures" GB 50009.

3 In limit state of bearing capacity, the design value of the fundamental combination effect Sd controlled by variable action shall be determined according to the following formula:

Sd=γGSGk+γQlSQ1k+γQ2ψc2SQ2k+……+γQnψcnSQnk (3.0.6-3)

Where,

γG——the partial coefficient of permanent action, valued according to the requirements of the current national standard "Load Code for the Design of Building Structures" GB 50009;

γQi——the partial coefficient of the ith variable action, valued according to the requirements of the current national standard "Load Code for the Design of Building Structures" GB 50009.

4 For fundamental combination controlled by permanent action, simplification rule may also be adopted, and the design value of the fundamental combination effect Sd may be determined according to the following formula:

Sd=1.35Sk (3.0.6-4)

Where,

Sk——the design value of action effect of standard combination.

3.0.7 The design working life of foundation shall not be less than that of building structure.

1 General Provisions
2 Terms and Symbols
2.1 Terms
2.2 Symbols
3 Basic Requirements
4 Geotechnical Classification and Index Properties
4.1 Geotechnical Classification
4.2 Engineering Index Properties
5 Foundation Design Calculation
5.1 Embedded Depth of Foundation
5.2 Bearing Capacity Calculation
5.3 Deformation Calculation
5.4 Stability Calculation
6 Foundation in Mountain Area
6.1 General Requirements
6.2 Foundation on Rock and Soil
6.3 Foundation on Compacted Fill
6.4 Landslide Prevention
6.5 Foundation on Rock
6.6 Karst and Sinkhole
6.7 Earth Slope and Gravity Retaining Wall
6.8 Rock Slope and Anchor Wall
7 Soft Ground
7.1 General Requirements
7.2 Usage and Treatment
7.3 Architectural Measurement
7.4 Structural Measurement
7.5 Massive Ground Surcharge
8 Foundation
8.1 Non-reinforced Spread Foundation
8.2 Spread Foundation
8.3 Strip Foundation under Columns
8.4 Raft Foundation of High-rise Buildings
8.5 Pile Foundation
8.6 Rock Bolt Foundation
9 Excavation Engineering
9.1 General Requirements
9.2 Excavation Engineering Exploration and Environmental Investigation
9.3 Earth Pressure and Water Pressure
9.4 Design Calculation
9.5 Internal Bracing of Support Structure
9.6 Soil Bolt
9.7 Excavation Engineering Inverse Practice
9.8 Excavation Engineering of Rock Mass
9.9 Underground Water Control
10 Inspection and Monitoring
10.1 General Requirements
10.2 Inspection
10.3 Monitoring
Appendix A Division of Rock Hardness and Rock Mass Integrity Degree
Appendix B Field Identification of Gravel Soil
Appendix C Key Points for Shallow Plate Load Testing
Appendix D Key Points for Deep Plate Load Testing
Appendix E Standardized Value for Shear Strength Parameters C and
Appendix F Contour of Seasonal Standardized Frost Depth in China
Appendix G Classification of Soil Expansion upon Freezing and Maximum Allowable Thickness of Frozen Earth above Building Foundation
Appendix H Key Points for Loading Test on Rock
Appendix J Requirements for Uni-axial Compressive Strength Testing on Rock
Appendix K Stress Influence Coefficient α and Average Stress Influence Coefficient
Appendix L Active Earth Pressure Coefficient ka for Retaining Wall
Appendix M Key Points for Pullout Resistance Testing on Rock Anchors
Appendix N Calculation of Subsequent Foundation Settlement under Massive Ground Surcharge
Appendix P Perimeter of Critical Section for Shearing and Polar Moment of Inertia Calculation
Appendix Q Key Points for Vertical Static Load Test on Single Pile
Appendix R Final Settlement Calculation for Pile Foundation
Appendix S Key Points for Lateral Load Test on Single Pile
Appendix T Key Points for Uplift Capacity Test on Single Pile
Appendix U Anti-shearing Sectional Width of Step and Cone-shape Pile Cap
Appendix V Stability Evaluation for Excavation Support Structures
Appendix W Anti-seepage Stability Evaluation for Foundation Pit
Appendix Y Key Points for Pre-stressed Earth Anchor Testing
Explanation of Wording in this Code
List of Quoted Standards

1 总则
1．0．1 为了在地基基础设计中贯彻执行国家的技术经济政策，做到安全适用、技术先进、经济合理、确保质量、保护环境，制定本规范。
1．0．2 本规范适用于工业与民用建筑(包括构筑物)的地基基础设计。对于湿陷性黄土、多年冻土、膨胀土以及在地震和机械振动荷载作用下的地基基础设计，尚应符合国家现行相应专业标准的规定。
1．0．3 地基基础设计，应坚持因地制宜、就地取材、保护环境和节约资源的原则；根据岩土工程勘察资料，综合考虑结构类型、材料情况与施工条件等因素，精心设计。
1．0．4 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 术语和符号
2．1 术语
2．1．1 地基 ground，foundation soils
支承基础的土体或岩体。
2．1．2 基础 foundation
将结构所承受的各种作用传递到地基上的结构组成部分。
2．1．3 地基承载力特征值 characteristic value of subsoil bearing capacity
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 重力密度(重度) gravity density，unit weight
单位体积岩土体所承受的重力，为岩土体的密度与重力加速度的乘积。
2．1．5 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。
2．1．6 标准冻结深度 standard frost penetration
在地面平坦、裸露、城市之外的空旷场地中不少于10年的实测最大冻结深度的平均值。
2．1．7 地基变形允许值 allowable subsoil deformation
为保证建筑物正常使用而确定的变形控制值。
2．1．8 土岩组合地基 soil-rock composite ground
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，ground improvement
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 ground，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
为扩散上部结构传来的荷载，使作用在基底的压应力满足地基承载力的设计要求，且基础内部的应力满足材料强度的设计要求，通过向侧边扩展一定底面积的基础。
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 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。
2．1．14 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。
2．1．15 基坑工程 excavation engineering
为保证地面向下开挖形成的地下空间在地下结构施工期间的安全稳定所需的挡土结构及地下水控制、环境保护等措施的总称。
2．2 符号
2．2．1 作用和作用效应
Ea——主动土压力；
Fk——相应于作用的标准组合时，上部结构传至基础顶面的竖向力值；
Gk——基础自重和基础上的土重；
Mk——相应于作用的标准组合时，作用于基础底面的力矩值；
pk——相应于作用的标准组合时，基础底面处的平均压力值；
p0——基础底面处平均附加压力；
Qk——相应于作用的标准组合时，轴心竖向力作用下桩基中单桩所受竖向力。
2．2．2 抗力和材料性能
a——压缩系数；
c——黏聚力；
Es——土的压缩模量；
e——孔隙比；
fa——修正后的地基承载力特征值；
fak——地基承载力特征值；
frk——岩石饱和单轴抗压强度标准值；
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；
w——土的含水量；
wL——液限；
wp——塑限；
γ——土的重力密度，简称土的重度；
δ——填土与挡土墙墙背的摩擦角；
δr——填土与稳定岩石坡面间的摩擦角；
θ——地基的压力扩散角；
μ——土与挡土墙基底间的摩擦系数；
v——泊松比；
φ——内摩擦角。
2．2．3 几何参数
A——基础底面面积；
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；
d——基础埋置深度，桩身直径；
h0——基础高度；
Hf——自基础底面算起的建筑物高度；
Hg——自室外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；
s——沉降量；
u——周边长度；
z0——标准冻结深度；
zn——地基沉降计算深度；
β——边坡对水平面的坡角。
2．2．4 计算系数
a——平均附加应力系数；
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；
φs——沉降计算经验系数。
3 基本规定
3．0．1 地基基础设计应根据地基复杂程度、建筑物规模和功能特征以及由于地基问题可能造成建筑物破坏或影响正常使用的程度分为三个设计等级，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 建筑和地基类型
甲级 重要的工业与民用建筑物
30层以上的高层建筑
体型复杂，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)
对原有工程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
位于复杂地质条件及软土地区的二层及二层以上地下室的基坑工程
开挖深度大于15m的基坑工程
周边环境条件复杂、环境保护要求高的基坑工程
乙级 除甲级、丙级以外的工业与民用建筑物
除甲级、丙级以外的基坑工程
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
非软土地区且场地地质条件简单、基坑周边环境条件简单、环境保护要求不高且开挖深度小于5．0m的基坑工程
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、乙级的建筑物，均应按地基变形设计；
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，且体型复杂的建筑；
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 表3．0．3所列范围内设计等级为丙级的建筑物可不作变形验算。
表3．0．3 可不作地基变形验算的设计
等级为丙级的建筑物范围
地基
主要
受力
层情
况 地基承载力特征值
fak(kPa) 80≤fak＜100 100≤fak＜130 130≤fak＜160 160≤fak＜200 200≤fak＜300
各土层坡度(％) ≤5 ≤10 ≤10 ≤10 ≤10
建
筑
类
型 砌体承重结构、框架结构
(层数) ≤5 ≤5 ≤6 ≤6 ≤7
单层排架结构(6m柱距) 单
跨 吊车额定起
重量(t) 10～15 15～20 20～30 30～50 50～100
厂房跨度
(m) ≤18 ≤24 ≤30 ≤30 ≤30
多
跨 吊车额定起
重量(t) 5～10 10～15 15～20 20～30 30～75
厂房跨度
(m) ≤18 ≤24 ≤30 ≤30 ≤30
烟囱 高度(m) ≤40 ≤50 ≤75 ≤100
水塔 高度(m) ≤20 ≤30 ≤30 ≤30
容积(m3) 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的范围(二层以下一般的民用建筑除外)；
2 地基主要受力层中如有承载力特征值小于130kPa的土层，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 地基基础设计前应进行岩土工程勘察，并应符合下列规定：
1 岩土工程勘察报告应提供下列资料：
1)有无影响建筑场地稳定性的不良地质作用，评价其危害程度；
2)建筑物范围内的地层结构及其均匀性，各岩土层的物理力学性质指标，以及对建筑材料的腐蚀性；
3)地下水埋藏情况、类型和水位变化幅度及规律，以及对建筑材料的腐蚀性；
4)在抗震设防区应划分场地类别，并对饱和砂土及粉土进行液化判别；
5)对可供采用的地基基础设计方案进行论证分析，提出经济合理、技术先进的设计方案建议；提供与设计要求相对应的地基承载力及变形计算参数，并对设计与施工应注意的问题提出建议；
6)当工程需要时，尚应提供：深基坑开挖的边坡稳定计算和支护设计所需的岩土技术参数，论证其对周边环境的影响；基坑施工降水的有关技术参数及地下水控制方法的建议；用于计算地下水浮力的设防水位。
2 地基评价宜采用钻探取样、室内土工试验、触探，并结合其他原位测试方法进行。设计等级为甲级的建筑物应提供载荷试验指标、抗剪强度指标、变形参数指标和触探资料；设计等级为乙级的建筑物应提供抗剪强度指标、变形参数指标和触探资料；设计等级为丙级的建筑物应提供触探及必要的钻探和土工试验资料。
3 建筑物地基均应进行施工验槽。当地基条件与原勘察报告不符时，应进行施工勘察。
3．0．5 地基基础设计时，所采用的作用效应与相应的抗力限值应符合下列规定：
1 按地基承载力确定基础底面积及埋深或按单桩承载力确定桩数时，传至基础或承台底面上的作用效应应按正常使用极限状态下作用的标准组合；相应的抗力应采用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按正常使用极限状态下作用的准永久组合，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、地基或滑坡稳定以及基础抗浮稳定时，作用效应应按承载能力极限状态下作用的基本组合，但其分项系数均为1．0；
4 在确定基础或桩基承台高度、支挡结构截面、计算基础或支挡结构内力、确定配筋和验算材料强度时，上部结构传来的作用效应和相应的基底反力、挡土墙土压力以及滑坡推力，应按承载能力极限状态下作用的基本组合，采用相应的分项系数；当需要验算基础裂缝宽度时，应按正常使用极限状态下作用的标准组合；
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Υ0不应小于1．0。
3．0．6 地基基础设计时，作用组合的效应设计值应符合下列规定：
1 正常使用极限状态下，标准组合的效应设计值Sk应按下式确定：
Sk＝SGk＋SQ1k＋Φc2SQ2k＋……＋ΦcnSQnk (3．0．6-1)
式中：SGk——永久作用标准值Gk的效应；
SQk——第i个可变作用标准值Qik的效应；
Φci——第i个可变作用Qi的组合值系数，按现行国家标准《建筑结构荷载规范》GB 50009的规定取值。
2 准永久组合的效应设计值Sk应按下式确定：
Sk＝SGk＋Φq1SQlk＋Φq2SQ2k＋……＋ΦqnSQnk (3．0．6-2)
式中：Φqi——第i个可变作用的准永久值系数，按现行国家标准《建筑结构荷载规范》GB 50009的规定取值。
3 承载能力极限状态下，由可变作用控制的基本组合的效应设计值Sd，应按下式确定：
Sd＝ΥGSGk＋ΥQlSQ1k＋ΥQ2Φc2SQ2k＋……＋ΥQnΦcnSQnk (3．0．6-3)
式中：ΥG——永久作用的分项系数，按现行国家标准《建筑结构荷载规范》GB 50009的规定取值；
ΥQi——第i个可变作用的分项系数，按现行国家标准《建筑结构荷载规范》GB 50009的规定取值。
4 对由永久作用控制的基本组合，也可采用简化规则，基本组合的效应设计值Sd可按下式确定：
Sd＝1．35Sk (3．0．6-4)
式中：Sk——标准组合的作用效应设计值。
3．0．7 地基基础的设计使用年限不应小于建筑结构的设计使用年限。