Some standard content:
Engineering Construction Standard Full-text Information System
Industry Standard of the People's Republic of China
Technical Code for Building Pile Foundations
Technical Code for Building Pile Foundations JGJ94—94
1994 Beijing
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Industry Standard of the People's Republic of China
Technical Code for Building Pile Foundations
Technieal Code for Building Pile Foundations FoundationsJGJ94—94
Editor: China Academy of Building ResearchApproval department: Ministry of Construction of the People's Republic of ChinaEffective date July 1, 1995
Engineering construction standard full text information system
Engineering construction standard full text information system
Notice on the release of the industry standard
"Technical Specifications for Building Pile Foundations"
Construction Standard [19947802]
According to the requirements of the former State Planning Commission's Letter [1987J78], the "Technical Specifications for Building Pile Foundations" edited by the China Academy of Building Research has been reviewed and approved as a mandatory industry standard, numbered KGJ9494, and will be implemented from July 1, 1995. This standard is managed by the China Academy of Building Research, the unit responsible for the construction engineering standards and technologies of the Ministry of Construction, and the specific interpretation and other work is the responsibility of the Foundation Institute of the China Academy of Building Research. If you find any problems or opinions during the implementation process, please inform the China Academy of Building Research.
This specification is published by the Standard and Norms Research Institute of the Ministry of Construction. Ministry of Construction of the People's Republic of China
December 31, 1994
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2 Terms, symbols...
2.2 Symbols
Basic design regulations
3.1/Basic information
3.2 Selection and arrangement of piles
3.3 Design principles
3.4 Pile foundations under special conditions||tt ||Pile foundation structure
4 Pile structure
2 Cap structure
5 Pile foundation calculation
51 Calculation of pile top effect:
5.2 Calculation of vertical bearing capacity of pile foundation
53 Calculation of pile foundation settlement.··
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54 Calculation of horizontal bearing capacity and displacement of pile foundation…·5.5 Calculation of bearing capacity and crack resistance of pile body
5.． Cap calculation…
Casting pile construction
61 Construction preparation·
General provisions
6.3 Mud wall bored cast-in-place piles·
6.4 Pipe sinking cast-in-place piles and internal rammed cast-in-place piles..··6.5 Dry operation bored cast-in-place piles
7 7.1 Fabrication of precast concrete piles
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7.2 Lifting, transportation and storage of precast concrete piles 7.3 Connection of precast concrete piles
Sinking of precast concrete piles
7.5 Fabrication of steel piles (steel pipe piles, H-shaped piles and other special-shaped steel piles)
Welding of steel piles
Transportation and storage of steel piles
7.8 Sinking of steel piles
Capping platform construction
General provisions
8.2 Excavation and backfilling of foundation pits
Steel bars and concrete
Quality of pile foundation engineering Quality inspection and acceptance
9.1 Quality inspection
9.2 Single pile bearing capacity test
Appendix A
Appendix B
Appendix C
Appendix D
Appendix E
Appendix F
Appendix G
Appendix D
Appendix 1
Acceptance data for pile foundation and pedestal engineering
Reference table for pile construction technology selection
Calculation of pile foundation subjected to horizontal load considering the pedestal (including underground wall), cooperative work of pile foundation and elastic resistance of soil·Single pile vertical compression static load test
Single pile vertical tension static load test
Single pile horizontal static load test·
Calculated according to inverted elastic foundation beam Strip pile foundation pedestal beam under the wall 144 Additional stress coefficient α, average additional stress coefficient α Pile foundation equivalent settlement coefficient type. Calculation parameter table·Explanation of terms used in this code
Additional explanation
List of editors, participating units and main drafters of this code Article explanation·
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1.0.1 In order to achieve advanced technology, economic rationality, safety and quality assurance in pile foundation design and construction. Formulate this code 1.0.2 This code applies to the design and construction of pile foundations for industrial and civil buildings (including structures).
1.0.3 The design and construction of pile foundations should comprehensively consider geological conditions, upper The design and construction shall be carefully considered based on the structural type, load characteristics, construction technical conditions and environment, and testing conditions.
1.0.4 This specification is formulated based on the basic principles of the "Uniform Standard for Building Structure Design" GBJ68-84. The symbols, units and terms related to building structures shall be adopted in accordance with the "Basic Terms, General Symbols and Measurement Units for Building Structure Design" GBJ83-85. 10.5 When adopting this specification, the soil classification shall be implemented in accordance with the current "Code for Design of Building Foundations"; the load value shall be implemented in accordance with the current "Code for Loads of Building Structures", the cross-section calculation of concrete piles and caps shall be implemented in accordance with the relevant provisions of the current "Code for Design of Concrete Structures"; the cross-section calculation of steel piles shall be implemented in accordance with the current "Code for Design of Steel Structures". For pile foundations in special soil areas and pile foundations under earthquake and mechanical vibration loads, the current relevant specifications shall still be implemented. Other contents not specified in this specification shall still comply with the provisions of the current relevant standards and specifications. Engineering Construction Standards Full Text Information System
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2Terms and Symbols
2.1Terminology
Pile foundation——
——It consists of a pile and a cap connected to the top of the pile. If the pile is completely buried in the soil and the bottom of the cap is in contact with the soil, it is called a low cap pile foundation; if the upper part of the pile is exposed to the ground and the bottom of the cap is above the ground, it is called a high cap pile foundation. Building pile foundations are usually low cap pile foundations.
Single pile foundation——An independent foundation that uses one pile (usually a large diameter pile) to bear and transfer the load of the superstructure (usually a column). Pile group foundation——A pile foundation composed of more than two piles. Pile group A single pile in a pile group foundation.
Composite pile——A pile that includes the soil resistance at the bottom of the cap. Vertical ultimate bearing capacity of a single pile——The maximum load corresponding to a single column before it reaches a failure state or deforms to the point where it is unsuitable for continued bearing under vertical load. It depends on the bearing resistance of the soil to the pile and the strength of the pile body material. It is generally controlled by the bearing resistance of the soil to the pile. For end-bearing piles, super-long piles and piles with defective pile body quality, it may be controlled by the strength of the pile body material.
Pile group effect
After the pile group foundation is subjected to vertical load, due to the interaction between the cap, pile and pile, its pile side resistance, pile end resistance, settlement and other characteristics change and are significantly different from those of a single pile. The bearing capacity is often not equal to the sum of the bearing caps of each single pile. This is called the pile group effect. The pile group effect varies under the influence of many factors such as soil properties, pile spacing, number of piles, pile length-diameter ratio, ratio of pile length to cap width, and pile construction method. The pile group effect coefficient is an indicator used to measure the magnitude of the reduction or increase of each component of the pile group bearing capacity due to the pile group effect, such as the pile group effect coefficient of side resistance, end resistance, and cap bottom soil resistance.
Pile side resistance Pile effect coefficient of pile group——the ratio of the average ultimate side resistance of piles in a pile group to the average ultimate side resistance of a single pile.
Pile end resistance Pile effect coefficient of pile group——the ratio of the average ultimate end resistance of piles in a pile group to the average ultimate end resistance of a single pile.
Pile side resistance and end resistance comprehensive pile effect coefficient——the ratio of the average ultimate bearing capacity of piles in a pile group to the ultimate bearing capacity of a single pile.
Soil resistance of pedestal base The ratio of the pile effect coefficient of pile group
to the ultimate resistance of foundation soil at the bottom of pedestal. Average ultimate soil resistance of pedestal base of a group
Negative friction——the downward friction of soil on the side surface of pile when the settlement of soil around pile body is greater than that of pile body due to self-weight consolidation, self-weight wetting, additional ground load, etc. The displacement of the pile and soil at a certain depth of the pile body is equal, and this point is called the neutral point. The neutral point is the dividing point between positive and negative friction. Pull-down load: For a single pile foundation, the cumulative value of the negative friction above the neutral point is the pull-down load. For the piles in the pile group foundation, the pile group effect of negative friction resistance must be considered, that is, the pull-down load should be reduced by multiplying the pull-down load of the single pile by the corresponding negative friction resistance pile group effect coefficient.
Occlusion effect: During the sinking process of the open pipe pile, part of the soil at the pile end is squeezed to the periphery, and part of it flows into the pipe to form a "soil plug". The soil plug will be compressed to a certain extent by the friction resistance of the pipe wall. The height of the soil plug and its degree of occlusion are related to many factors such as soil properties, pipe diameter, wall thickness and depth of entry into the bearing layer. The degree of occlusion directly affects the end resistance and destructive characteristics and the bearing capacity of the pile. This is called the "occlusion effect". 2.2 Symbols
22.1 Resistance and material properties
Standard value of ultimate lateral resistance of the first layer of single pile: - Standard value of ultimate end resistance of single pile;
Standard value of ultimate resistance of foundation soil at the bottom of pedestal
Standard value of total ultimate lateral resistance and total ultimate end resistance of single pile; Qsk, Qp
Standard value of vertical ultimate bearing capacity of single pile; Q
Standard value of total ultimate resistance of foundation soil at the bottom of pedestal corresponding to any composite foundation pile
R-Design value of vertical bearing capacity of composite foundation pile or foundation pile in pile foundation; Engineering Construction Standard Full-text Information System
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-Standard value of the ultimate pull-out bearing capacity of a single pile, Uk
U-Standard value of the ultimate pull-out bearing capacity of any pile in a group of piles; Rhi
-Design value of the horizontal bearing capacity of a composite pile or pile, design value of the horizontal bearing capacity of a single pile,
Specific penetration resistance value of a single-bridge probe for static penetration testing; Average side resistance and average end resistance of double-bridge probes for static penetration testing; Proportional coefficient of the horizontal resistance coefficient of foundation soil on the pile side; fre-Saturated uniaxial compressive strength of rock;
-Design value of tensile and compressive strength of concrete; Compression modulus of soil:
Soil density and effective density.
Actions and effects
Design value of vertical force acting on the top surface of pile foundation cap; Design value of white weight on pile foundation cap and cap soil, Design value of vertical force on the ith composite pile or pile; Moment of external force acting on the bottom surface of cap on the x and y axes passing through the centroid of pile group;
Design value of horizontal force acting on the bottom surface of cap; Design value of horizontal force acting on any composite pile or pile, Standard value of average negative friction of single pile;
Standard value of pull-down load acting on the side of single pile, QQ
-Moment of external force acting on any composite pile or pile in pile group. 1. Standard value of pull-down load of pile foundation; Design value of frost heave force in all directions;
Final settlement of pile foundation
2.2.3 Geometric parameters
&——pile center distance;
1——pile body length;
1. Design diameter of pile body
1. Design diameter of pile end expansion;
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1. Outer diameter of steel pipe pile;
—Pile body circumference,
A. ——Net area of capping platform bottom;
——Cross-sectional area of pile body;
ys, Yp
Se, Sp
Pile end area,
-Converted cross-sectional area of pile body;
Converted depth of pile:
Capping platform length;
Capping platform width;
Calculated depth of pile foundation settlement (measured from the pile end plane). Calculation coefficient
Importance coefficient of building pile foundation;
Partial coefficient of pile side resistance and pile end resistance; Partial coefficient of comprehensive resistance of pile side resistance and end resistance; Partial coefficient of impedance of subsoil under cap;
Group pile effect coefficient of pile side resistance and pile end resistance; -Comprehensive group pile effect coefficient of pile side resistance and end resistance; Group pile effect coefficient of subsoil resistance under cap
Frost heave influence coefficient;
Correction coefficient of side resistance and end resistance of rock-embedded section; Size effect coefficient of side resistance and end resistance of large diameter pile; Side resistance and soil squeezing effect coefficient of steel pipe pile,
Blocking effect coefficient of pile end of scattered mouth pile;
-Friction coefficient between subsoil under cap and foundation soil;
-Equivalent settlement coefficient of pile foundation
Empirical coefficient for settlement calculation of pile foundation;Www.bzxZ.net
Construction technology coefficient of pile foundation;
Ratio of elastic modulus of steel bar to elastic modulus of concrete. Engineering Construction Standard Full Text Information System
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3 Basic Design Provisions
3.1 Basic Data
3.11 Pile foundation design should have the following data
3.1.1.1 Geotechnical Engineering Investigation Data
(1) Engineering geological reports and drawings compiled in accordance with the requirements of the current "Geotechnical Engineering Investigation Code";
(2) Geotechnical data required for the design of pile foundations according to the two limit states; Soil physical and mechanical performance index values;
(3) Clear judgment, conclusion and prevention plan for adverse geological phenomena at the construction site, such as landslides, collapses, debris flows, karst, soil caves, etc.;(4) Determined and predicted groundwater levels and groundwater chemical analysis conclusions;(5) On-site or other reference pile test data and experience data of similar pile foundation projects nearby
(6) Liquefaction stratum data provided according to the seismic fortification intensity in the seismic fortification area (7) Data on frost heave, collapsibility and expansion of foundation soil. 3.1.1.2 Data on construction site and environmental conditions (1) Plan of the construction site, including the distribution of transportation facilities, high-voltage overhead lines, underground pipelines and underground structures;
(2) Safety level, foundation type and burial depth of adjacent buildings;(3) Supply conditions of water, electricity and related construction materials;(4) Vibration and noise protection requirements for surrounding buildings and slopes;(5) Mud discharge and soil abandonment conditions.
3.1.1.3 Relevant information of buildings
(1) General layout of the building
(2) Structural type, load and requirements of the building's use or production equipment on the vertical and horizontal displacement of the foundation;
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(3) Safety level of the building;
(4) Seismic fortification intensity and building (seismic) category of the building. 3.1.1.4 Data on construction conditions
(1) Construction machinery and equipment conditions, pile making conditions, power conditions and adaptability to geological conditions;
(2) Construction machinery and equipment access and on-site operation conditions. 3.115 Various pile types for design comparison and their feasibility of implementation 3.1.2 In addition to meeting the relevant requirements of the current survey specifications, the detailed survey of pile foundations shall also meet the following requirements:
3.1.2.1 Spacing between survey points
(1) For end-bearing piles and rock-embedded piles: Mainly determined by the top slope of the bearing layer at the pile end, it is preferably 12 to 24 m. When the slope of the layer exposed by two adjacent exploration points is greater than 10%, the exploration points should be appropriately increased according to the specific engineering conditions; (2) For friction piles: exploration points should be arranged every 20 to 30 m, but when the properties or state of the soil layer varies greatly in the horizontal direction, or there is a soil layer that may affect the pile formation, the exploration points should be appropriately increased;
(β) Under complex geological conditions, the exploration points of the single pile foundation under the column should be arranged according to the pile line, and one exploration point should be set for each pile.
3.1.2.2 Exploration Depth
(1) 1/3 to 1/2 of the exploration holes are arranged as control holes, and the safety level is the first-level building pile foundation. At least 3 control holes should be arranged on the site, and the safety level is the second-level building pile foundation. There should be no less than 2 control holes. The depth of the control hole should penetrate the thickness of the compression layer below the pile end plane, and the general exploration hole should be 3 to 5 meters below the pile end plane; (2) The drilling depth of the rock-embedded pile should be no less than 3 to 5 times the pile diameter; when the bearing rock layer is thin, there should be a part of the drilling to drill out the five layers. The distribution of karst caves, karst grooves, stalagmites, etc. in the karst area should be investigated. 3.1.2.3 Each stratum within the exploration depth range should be subjected to indoor tests or in-situ tests to provide the parameters required for the design. Engineering Construction Standard Full-text Information System
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