JGJ 123-2000 既有建筑地基基础加固技术规范 英文版.doc

中华人民共和国行业标准中华人民共和国行业标准 Industrial Standard of the Peoples Republic of ChinaJGJ 123-2000既既有有建建筑筑地地基基基基础础加加固固技技术术规规范范Technical Code for Improvement of Soil and Foundation of Existing BuildingsBeijing, 2000本英文版为内部资料，仅供参考，以中文 版为准。 The Chinese version of standards has precedence to their English translations which are only for internal reference. 1 中华人民共和国行业标准中华人民共和国行业标准Industrial Standard of the Peoples Republic of China既既有有建建筑筑地地基基基基础础 加加固固技技术术规规范范 Technical Code for Improvement of Soil and Foundation of Existing BuildingsJGJ 123-2000Mainly prepared by: Research Institute of Construction Science of the Peoples Republic of ChinaApproved by: Ministry of Construction of the Peoples Republic of China Implementation date:June 1, 2000 2 Notice on issuing the industrial standard “Technical Code for Improvement of Soil and foundation of Existing Buildings”Jian Biao 2000 No.35 As per the requirement in “Notice on Issuing Compilation and Revision Project Plan for Construction Project Industrial Standards of 1993” (Jian Biao 1993 No. 285), “Technical Code for Improvement of Soil and Foundation of Existing Buildings” compiled by Research Institute of Construction Science of Peoples Republic of China is hereby reviewed and approved as compulsory industrial standard, number as JGJ 123-2000, and should come into force from June 1, 2000. The subject standard will be managed and interpreted by the Research Institute of Construction Science of P. R. China which is the technical responsible unit for the Ministry of Construction. The Research Institute of Standard Quotas organized China Construction Publishing House to publish the standard.Ministry of Construction of Peoples Republic of ChinaFebruary 12, 2000 3 ForwardAs per the requirement of Jian Biao 1993 No. 285 issued by the Ministry of Construction, the code compilation team hereby compiled this code through extensive investigation and research, with many research results home and abroad and a large amount of construction practice experiences summarized, and through opinions broadly solicited.The technical contents of this code many consist of general rules, symbols, basic stipulation, verification of soil and foundation, foundation calculation, improvement methods of soil and foundation, remedy and prevention of soil and foundation incident or accident, improvement through added layers, reinforcement to rectify incline or replacement, and etc.The code is managed and interpreted by the Research Institute of Construction Science of P. R. China which is the technical responsible unit for the Ministry of Construction.The code is mainly compiled by the Research Institute of Construction Science of P. R. China (Address: 30 East Third North Ring Road, Beijing; Postcode 100013)The code is jointly compiled by Tongji University, Nothern Communication University, Research Institute of Construction Science of Fujian province.The code is mainly compiled by following personnel: Zhang Yongjun, Ye Shuqi, Tang Yeqing, and Hou Weisheng. 4 Table of Content 1 General Rules.5 2 Symbols .5 3 Basic stipulation.6 4 Verification of Soil and Foundation.7 5 Foundation Calculation.9 6 Methods for Improvement of Soil and Foundation .11 7 Remedy and Prevention of Soil and Foundation Incident.27 8 Modification to Add Stories .32 5 1 General Rules1.0.1 In order to execute the technical and economical policy of the country during the design and construction of the improvement of soil and foundation, the code is compiled so that “advanced technology, reasonable economy, safety and adequacy, ensured quality and protected environment” can be achieved.1.0.2 This code is applicable to design and construction of any improvement to soil and foundation caused by inadequate soil investigation, design, construction, or operations, by increased load, incline, displacement, reconstruction or protection of ancient buildings, or by nearby new buildings, excavation of deep foundation pits, new underground services, or natural disaster.1.0.3 The design and construction of improvement of soil and foundation of existing buildings, besides meeting the requirements of this code, should meet the requirement of relevant national compulsory standards which is in force.2 SymbolsA Bottom area of foundation d Pile diameter d Diameter of lime pile after expansion Ep Compression modulus of pile bodyEs Compression modulus of soil between piles Esp Compression modulus of compound soil layer F Design value of the vertical force on the top surface of foundation from upper structure after reinforcement of foundation or load increased. f Design value of foundation bearing capacity fs,k Standard value of bearing capacity of soil between piles after improvement fp,k Standard value of bearing capacity of pile unit section fsp,k Standard value of bearing capacity of compound foundation G Design value of foundation weight and weight of soil on top of foundation l1 Line distance of piles l2 Row distance of piles M Design value of moment applied to the bottom of foundation after improvement or increased load m Replacement ratio of area Na Design value of bearing load for uplifting point 6 N Number of uplifting points p Design value of average pressure on the bottom of foundation after improvement or increased load pmax Design value of maximum pressure along the side of the bottom of foundation after improvement or increased load pmin Design value of minimum pressure along the side of the bottom of foundation after improvement or increased load Q Design value of total load for building q Lime volume for each meter of lime pile s Final settlement of foundation s0 Settlement achieved before improvement or increased load s1 Settlement achieved after improvement or increased load s2 Settlement to be achieved under original building load W Sectional modulus at the bottom of foundation after improvement or increased load c Expansion factor3 Basic stipulation3.0.1 Before improvement of soil and foundation of existing buildings, soil and foundation should be examined to enable design and construction. The examination of soil and foundation, and design and construction of improvement should be carried out by companies with relevant certifications and by professional personnel with experiences.3.0.2 Design of improvement of soil and foundation of existing buildings should be carried out according to the following steps:1 When selecting method for improvement, objective of improvement, joint function of upper structure, foundation and soil should be considered to decide initially whether soil, foundation, stiffness of upper structure or combination of soil and foundation should be improved. 2 After the initial schemes are selected, they should be compared through expected achievement, difficulty of construction, material availability and delivery conditions, safe constructability, impact to adjacent building or environment, conditions of construction equipment, construction period and cost, so that a optimum scheme can be selected.3.0.3 The construction people should understand the objective of improvement, theory, technical requirement and quality standard for the improvement project undertaken. 7 Dedicated personnel are required for quality control through strict monitoring. Whenever an abnormal condition is observed, meeting should be held with designers and relevant department to analyze the problem and find solutions.3.0.4 A dedicated organization is required to supervise quality during construction. When the construction is complete, quality inspection and acceptance should be conducted.3.0.5 Settlement observation is required during construction of improved to soil and foundation. For buildings of importance or of strict restriction of settlement, settlement observation should be continued after the improvement until it becomes stable. Adjacent buildings and underground services should be monitored at the same time.4 Verification of Soil and Foundation4.1 Verification of Soil4.1.1 The following steps should be observed when examining soil of existing buildings,1 Collect geotechnical investigation information, design documents and drawings of foundations for existing buildings and upper structure, construction recorded of concealed parts, and as-built drawings. 2 The following things should be analyzed when studying the original geotechnical investigation information. 1) Distribution and evenness of subsoil, weak underlying layer, special soil, gullies, ditches, rivers, tombs, caves, and holes. 2) Physical and mechanical properties of subsoil. 3) Water level and corrosivity of groundwater 4) Liquefaction characteristic of silt or sand, and earthquake characteristic of soft soil 5) Stability of site 3 Investigate the current condition of the building, actual working load, settlement, and settlement stability, differential settlement, distortion, incline and crack etc, and find causes. 4 Investigate adjacent buildings, underground services, and pipeline. 5 Work out inspection method to verify the soil based on the objective of improved, together with information collected and analyses of information.4.1.2 The following methods can be adopted for inspection of soil according to improvement requirement and site condition. 8 1 Drilling, pit exploration, channel exploration, or earth physical method can be adopted. 2 Indoor physical mechanical property test can be carried out on undisturbed soil. 3 In-situ tests like load test, cone penetration test, standard penetration test, dynamic penetration test, cross-board shear test or side pressure test can be adopted.4.1.3 Inspection of soil of existing buildings should comply the following requirements.1 According to the importance fo the building and original geotechnical investigation information, supplementary borehole or in-situ test hole should be provided to find out subsoil distribution and soil physical and mechanical properties. Holes should be close to foundation. 2 For important buildings that require adding stories or increase load, it is suitable to take undisturbed soil and carry out indoor physical mechanical property test or load test under the foundation.4.1.4 When evaluating soil of existing building, the following requirements should be met.1 According to the inspection result, together with local experience, a compressive evaluation of the soil should be prepared. 2 Decide whether it is necessary to improve soil and provide recommendations of improvement method based on the soil condition and upper structure.4.2 Verification of foundation4.2.1 Inspection of foundation of existing building should be carried out according to the following steps. 1 Collect design and construction documents for foundation, upper structure, and pipeline, and as-built drawings. Understand the actual load on different parts of the building. 2 Site proof is required. Exploration channel may be required to verify foundation type, material, dimension, and embedded depth. Examine crack in the foundation, corrosiveness, degree of damage, strength and grade of foundation materials. If the building inclines, then degree of incline and distortion should be investigated as well. For piled foundations, pile depth, bearing layer and pile quality should also be investigated.4.2.2 The following methods can be adopted for the inspection of foundation of existing building. 1 Visual check of foundation 9 2 Initial check with hand hammer to find out foundation quality. Find out strength or grade of foundation material using non-destructive method or core-taking method. 3 Check rebar diameter, number of piles, location, and corrosiveness. 4 Observe settlement of pile foundation.4.2.3 When evaluating foundation of existing building, the following requirements should be met. 1 Evaluate completeness of the foundation based on cracks, corrosiveness, degree of damage and grade of materials. 2 Calculate bearing capacity and deformation based on the actual load and deformation characteristics. Decide whether it is necessary to improve, and recommend method of improvement.5 Foundation Calculation5.1 Calculation of bearing capacity5.1.1 When the foundation of existing building need to be improved or the load is to be increased, the bearing capacity of soil should be calculated in accordance with following requirements. When the axial load worksp<=f (5.1.1-1) Where, p design value of average pressure at the bottom of foundation after improved or increased load. f Design value of soil bearing capacity, which should be determined based on the standard value determined through this code in accordance with current national standard “Code for building foundation design” (GBJ 7). For foundation that requires improvement, the standard value of soil bearing capacity should be determined through examination after the improvement. For soil with increased load, standard value of soil bearing capacity should be determined through examination before load is increased. For buildings with stabilized settlement, when adding stories, article 8.2 of this code may be referred to determine standard value of soil bearing capacity.When the eccentric load works, besides meeting the requirement of formula 5.1.1-1, the following formula should be met as well.pmax<=1.2f (5.1.1-2) Where, 10 pmax design value of maximum pressure along the bottom of foundation after improvement or increased load.5.1.2 Pressure at the bottom of foundation after improvement or increased load may be determined through the following formula When the axial load works,p=(F+G)/A (5.1.2-1) Where, F design value of vertical force on the top of foundation from upper structure after improvement or increased load G design value of foundation weight and soil weight on top of foundation. If below water level, floating force should be deducted. A foundation bottom areaWhen the eccentric load works,pmax = (F+G)/A + M/W (5.1.2-2)pmin = (F+G)/A - M/W (5.1.2-3) Where, M design value of moment