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1、本英文版為內(nèi)部資料，僅供參考，以中文版為準(zhǔn)。The Chinese version of standards has precedence to their English translations which are only for internal reference.中華人民共和國行業(yè)標(biāo)準(zhǔn)Industrial Standard of the Peoples Republic of China JGJ 123-2000既有建筑地基根底加固技術(shù)標(biāo)準(zhǔn)Technical Code for Improvement of Soil and Foundation of Existing Buildi
2、ngsBeijing, 2000中華人民共和國行業(yè)標(biāo)準(zhǔn)Industrial Standard of the Peoples Republic of China既有建筑地基根底加固技術(shù)標(biāo)準(zhǔn)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
3、Construction of the Peoples Republic of China Implementation date:June 1, 2000Notice on issuing the industrial standard “Technical Code for Improvement of Soil and foundation of Existing BuildingsJian Biao 2000 No.35As per the requirement in “Notice on Issuing Compilation and Revision Project Plan f
4、or 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 sta
5、ndard, 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 Standa
6、rd Quotas organized China Construction Publishing House to publish the standard.Ministry of Construction of Peoples Republic of ChinaFebruary 12, 2000ForwardAs per the requirement of Jian Biao 1993 No. 285 issued by the Ministry of Construction, the code compilation team hereby compiled this code th
7、rough 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, verificatio
8、n 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 Resea
9、rch 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 joi
10、ntly 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.Table of Content1 General Rules52 Symbols53 Basic stipulation
11、64 Verification of Soil and Foundation75 Foundation Calculation96 Methods for Improvement of Soil and Foundation117 Remedy and Prevention of Soil and Foundation Incident278 Modification to Add Stories321 General Rules In order to execute the technical and economical policy of the country during the
12、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. This code is applicable to design and construction of any improvement to soil and
13、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. The des
14、ign 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 foundationd Pile diameterd Diameter of lime pile after ex
15、pansionEp Compression modulus of pile bodyEs Compression modulus of soil between pilesEsp Compression modulus of compound soil layerF 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 foundat
16、ion bearing capacityfs,k Standard value of bearing capacity of soil between piles after improvementfp,k Standard value of bearing capacity of pile unit sectionfsp,k Standard value of bearing capacity of compound foundationG Design value of foundation weight and weight of soil on top of foundationl1
17、Line distance of pilesl2 Row distance of pilesM Design value of moment applied to the bottom of foundation after improvement or increased loadm Replacement ratio of areaNa Design value of bearing load for uplifting pointN Number of uplifting pointsp Design value of average pressure on the bottom of
18、foundation after improvement or increased loadpmax Design value of maximum pressure along the side of the bottom of foundation after improvement or increased loadpmin Design value of minimum pressure along the side of the bottom of foundation after improvement or increased loadQ Design value of tota
19、l load for buildingq Lime volume for each meter of lime piles Final settlement of foundations0 Settlement achieved before improvement or increased loads1 Settlement achieved after improvement or increased loads2 Settlement to be achieved under original building loadW Sectional modulus at the bottom
20、of foundation after improvement or increased loadc Expansion factor3 Basic stipulation 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 imp
21、rovement should be carried out by companies with relevant certifications and by professional personnel with experiences. 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 imp
22、rovement, 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
23、 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. The construction people should und
24、erstand the objective of improvement, theory, technical requirement and quality standard for the improvement project undertaken. Dedicated personnel are required for quality control through strict monitoring. Whenever an abnormal condition is observed, meeting should be held with designers and relev
25、ant department to analyze the problem and find solutions. A dedicated organization is required to supervise quality during construction. When the construction is complete, quality inspection and acceptance should be conducted. Settlement observation is required during construction of improved to soi
26、l 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 Ve
27、rification of Soil 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 drawin
28、gs.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 lev
29、el and corrosivity of groundwater4) Liquefaction characteristic of silt or sand, and earthquake characteristic of soft soil5) Stability of site3 Investigate the current condition of the building, actual working load, settlement, and settlement stability, differential settlement, distortion, incline
30、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. The following methods can be adopted for inspection
31、 of soil according to improvement requirement and site condition.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
32、 penetration test, dynamic penetration test, cross-board shear test or side pressure test can be adopted. 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
33、 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 phy
34、sical mechanical property test or load test under the foundation. 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 n
35、ecessary to improve soil and provide recommendations of improvement method based on the soil condition and upper structure.4.2 Verification of foundation Inspection of foundation of existing building should be carried out according to the following steps.1 Collect design and construction documents f
36、or 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, corros
37、iveness, 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. The following methods can be adopted f
38、or the inspection of foundation of existing building.1 Visual check of foundation2 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, an
39、d corrosiveness.4 Observe settlement of pile foundation. 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 deform
40、ation 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 capacity When the foundation of existing building need to be improved or the load is to be increased, the
41、bearing capacity of soil should be calculated in accordance with following requirements.When the axial load works p=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 ba
42、sed 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
43、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 e
44、ccentric 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,pmax design value of maximum pressure along the bottom of foundation after improvement or increased load. Pressure at the bottom of foundation after improvem
45、ent or increased load may be determined through the following formulaWhen 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 loadG design value of foundation weight and soil weight on top of fou
46、ndation. 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 applied to the bottom of foundation after improvement or increased loadW sectional modul
47、us of foundation bottom after improvement or increased load.pmin design value of minimum pressure along foundation bottom after improvement or increased load. When there is weak underlying layer within the bearing layers of foundation, the bearing capacity of weak underlying layer should be calculat
48、ed. For existing buildings on a slope or adjacent to deep foundation pit, soil stability should be calculated as well.5.2 Calculation of Soil Deformation The calculated value of soil deformation after improvement or inreased load should not exceed the allowable value in the current national standard
49、 “Code for Building Foundation Design (GBJ 7). The final settlement of foundation for existing building after soil and foundation improvement or increased load shall be determined through the following formula. s=s0+s1+s2 (5.2.2)Where,s final settlement of foundations0 settlement achieved before imp
50、rovement or increased load, which can be determined through settlement observation information or estimated according to local experience.s1 settlement achieved after improvement or increased load. If soil and foundation are improved, the value can be calculated with the compression modulus after im
51、provement. If the load is increased, the value can be calculated with the compression modulus before increased load.s2 - settlement to be achieved under original building load. The value can be estimated based on the settlement observation information or local experience. If the foundation settlemen
52、t under original building load is stabilized, then the value should be zero. Calculation of foundation settlement may be referred to the current national standard “Code for Building Foundation Design (GBJ 7).6 Methods for Improvement of Soil and Foundation6.1 Mortar Filling Method6.1.1 The method is
53、 applicable when cracks are found in foundations due to uneven settlement, frost heaving or other reasons. When the method is applies, first drill a hole at the crack. The filling tube can be 25mm in diameter. Angle between the hole and the horizon should be no less than 30 degrees. The diameter of
54、the hole should be 2-3mm greater than the diameter of the filling tube. The distance between holes may be 0.5 to 1.0 meter. Cement Mortar can be used as filling material. Filling pressure can be 0.1 to 0.3 Mpa. If the mortar is not going inside, the pressure maybe increased to 0.6 Mpa slowly. If the
55、 filling material is not going inside for 10 to 15 minutes, filling can be stopped. The effective diameter of filling is 0.6 to 1.2 meters. For single foundations, holes on each side of the foundation should be no less than two. For strip foundations, construction should be carried out by sections,
56、with each section between 1.5 to 2.0 meters.6.2 Foundation Bottom Enlargement Method When the bearing capacity of the foundation or the size of the foundation for the existing building can not meeting design requirement, foundation bottom enlargement method can be adopted. Concrete or reinforced con
57、crete may be used to make the bottom of foundation bigger. The design and construction should meet the following requirements when making the bottom of foundation bigger.1. If the foundation is under eccentric load, asymmetrical enlargement can be adopted while if the foundation is under central loa
58、d, symmetrical enlargement.2. The surface of original foundation should be made rough and washed clean, and a layer of high-strength cement mortar or concrete agent to increase the adhesive force of old concrete foundation and new concrete foundations.3. For the enlarged area, a compacted blinding l
59、ayer of the same thickness and materiel as the original blinding should be used.4. When using concrete to improve the foundation, the dimension of added concrete should meeting the allowable height and width ration for stiff foundation stipulated in the current national standard “Code for Building F
60、oundation Design (GBJ 7). Anchor re-bar should be placed at certain distance along the height of the foundation.5. When using reinforced concrete to improve the foundation, the main re-bars in the added part should be welded to the main re-bars in the original foundation.6. For the improvement to st
61、rip foundation, sections of 1.5 to 2.0 meters should be planned, and construction should be carried by batches and sections at different times. When concrete or reinforced concrete is not suitable for making the bottom of foundation bigger, single foundation may be changed into strip foundation, ori
62、ginal strip foundation to cross strip foundation or raft foundation, or original raft foundation to box foundation.6.3 Foundation Deepen Method The method is applicable when good subsoil layer exists near grade, which can be used as bearing layer, and with low water table. Make the original foundati
63、on deeper, so that it sits on a better bearing layer to meet the bearing and deformation requirements of the design. When the water table is high, dewater or draining measures should be carried out. The following steps should be observed when making foundation deeper.1. Excavate a 1.2 meter long, 0.9 meter wide vertical pit along the foundation of existing buildings by sections or batches. If the pit wall can not be uprig
JGJ 123-2000 既有建筑地基基礎(chǔ)加固技術(shù)規(guī)范 英文版
