ENGLISH 加筋土挡土墙施工方法陈述2011.12.21.docx

Sri Lanka Colombo-Katunayake Expressway (CKE) ProjectMethod Statement for Reinforced Earth Retaining Wall Construction CKE/CST/MS-510ACHINA METALLURGICAL GROUP CORPORATIONISSUEREVISIONDATEPREPARED BYAPPROVEDQAMPCECRADraft21st Dec,2011Cui SongmingL.A.GunawardhanaZhang QiDong He PingContents1.0 Objective12.0 Scope of Application13.0 Documents for Reference14.0 Responsibility15.0 Detailed Construction Method25.1 Main Material Quality Requirement25.2 Equipment and Labour35.3 Retaining Wall Construction Workmanship45.4 Reinforced Earth Retaining Wall Construction for every section of 50-100m65.5 Insepction and Testing Plan115.6 Reinforced Earth Retaining Wall Quality Control Standards126.0 Safety and Environment Management137.0 Quality Record Document/Result138.0 Appendix13Appendix 1：Retaining Wall Construction Inspection and Test Plan21CKE/CST/MS-510 (Rev.A) Page 1 of 1IssueA,Issued for ERs ReviewMethod Statement for Reinforced Earth Retaining Wall Construction CKE/CST/MS-510A1.0 ObjectiveThe objective of this method statement is to provide a detailed guidance for how to control the construction of Reinforced Earth Retaining Wall so as to ensure the construction of Reinforced Earth Retaining Wall could be fulfilled systematically, correctly and effectively.2.0 Scope of ApplicationThis method statement is applicable for the construction of all Reinforced Earth Retaining Walls within the scope of CKE Project Contract.3.0 Documents for ReferenceDesign Drawings Concurred by ER for Reinforced Earth Retaining Wall Construction、Clause 6 of JTG F80/12004CKE/PQP/01-Project Quality PlanCKE/ITP/01- Project Inspection and Test PlanCKE/SMP/01- Project Safety Management PlanCKE/EMP/01-Project Environment Management Plan4.0 Responsibility Construction Manager（CSM）：Responsible for managing overall site construction, quality，environmental and safety issues and ensures all the construction teams to operate in accordance with the construction plan, and approved Method Statement.Site Engineer (SE)：To ensure effective implementation of Method Statement and to give technical instructions timely at site and fill all the forms regarding technical, quality check, records and inspection spreadsheets and carry out the rectifications to issues.Foreman: Specificly responsible for sectional construction implementation of the Reinforced Earth Retaining Wall construction so as to ensure construction process & control will be carried out in accordance with this Method Statement.Quality Assurance Manager（QAM）：Review and approve Method Statement，responsible for check ，acceptance of quality Holding points and release them during the construction, ensure construction work sequence and quality meet the requirements of codes and standards, process control conforms to the Project Quality Plan and Inspection and Test Plan. Quality Engineer/Quality Inspector（QE/QI）:Supervise the construction process and quality control, and responsible for quality inspection and acceptance. Safety Manager（SM）：Supervise and implement various construction safety measures and take action to rectify existing problems, ensure all the various sub works to be carried out strictly in accordance with the Safety Management Plan for the Project.Environmental Manager（EM）：Supervise and conduct various construction environmental protection measures and urge rectification of existing problems, ensure all the various sub works to be carried out strictly in accordance with the Environmental Protection Management Plan for the Project. A list of names for each function above for all wall sections:CSM: Mr. Li hangSE: Mr.Feng anForeman: Mr.Jia yan mingQAM: Mr. L.A.GunawardhanaQE/QI: Mr.SiriraSM: Mr.Ma dingEM: Mr.Udaya5.0 Detailed Construction Method5.1 Main Material Quality Requirement5.1.1 Geogrid Quality Requirement Geogrid quality shall comply with the design requirements. Geogrid quality certificate will have to be approved by ER.5.1.2 Filling Material Quality Requirement Filling material of reinforced retaining wall shall comply with the design requirements. Sea sand will have been approved by ER.5.1.3 Blocks Quality Requirement The reinforced earth blocks wall shall be produced in accordance with MS-212A, and pass the acceptance. 5.2 Equipment and Labour 5.2.1 Equipment Distributed for Each Working Section Main Machinery and Equipment Allocation Table for every section of 50-100m，construction rate of wall face is 9m2(120pieces) per day Table1No.Machine TypeQty. Remarks 1Back hoe or JCB1 Drain ditch, foundation pit excavation2Carpenter equipment4Used for foundation formwork processing3Truck mixer4Concrete transportation4Loader(3m3)1Concrete transportation5Poker vibrator(5cm)3 Concrete transportation6Dump truck(10m3)4Filler transportation 7Dozer1Filler levelling 8Grader1Filler levelling9Water pump(4.8KW)/bowser(12tons)1Watering for filler（if necessary）10Watering Pipe200mAs the actual need to adjust 11Mini compactor1Filler rolling 12Vibratory compactor1Filler rolling13Plate vibrating tamper1 Used for filler rolling 1m inside to the retaining wall blocks14Level bar(0.5m)1Check the smoothness of the wall15Rubber mallet1Ajust the blocks of the wall16Plumb bob1Check the Vaticality of the wallThe quantity, model of the equipments could be allocated or adjusted as the actual situation and working quantities（if necessary）. 5.2.2 Labour distribution for each working section：QI- 1 personForeman- 1 personCarpenter- 4personsElectrician 1person Pump truck driver- 1 person vibration worker- 3 personsdozer operator - 1 personGrader operator- 1 personExcavator or JCB operator - 1 person roller driver- 2 personsVehicle reversing controller- 1 personDump truck driver- 4 personsworker -10 persons5.3 Retaining Wall Construction Workmanship Reinforced Earth Retaining Wall Construction Flow ChartConstruction preparation(Setting out etc.)MS approvedSubbase treatment(if necessary), DCP test(in accordance with the drawings) Foundation formwork erectionNQE/QAM inspect for qualified or not?(Hold Point)YC20 concreting Blocks installation, filling & compactionNQE/QAM inspect and test for qualified or not? (HP)YInstallation of geogridNQE/QI inspect for qualified or not? (HP)YRepeat the aforesaid procedure Next procedure5.4 Reinforced Earth Retaining Wall Construction for every section of 50-100mIf the reinforced earth retaining wall is required at both sides of subgrade, then they will be constructed simultaneously; if retaining wall is only at one side, then the retaining wall at that side will be carried out along with the embankment slope at the other side to ensure the whole breadth synchronization. For the curve section construction will be carried out in small sections , the section length is depend on radius of the curve, case by case it will be handled.5.4.1 Retaining Wall Subbase TreatmentSet out the side line for the retaining wall and grid locations in accordance with the concurred drawings, and positioned them with stakes,every 10m one stake(based on curvature,ex.3+209-5m). The concrete foundation area of retaining wall shall be cleaned and properly leveled and tamped.Unsuitable material at foundation soil should be removed(if necessary) and the depth removed can be specified according to the site situation. If necessary, the temporary drain will be provided. DCP test （150Kpa）will be taken in accordance with the requirement of the approved drawings prior to C20 base concreting.Settlement plates will be installed according to the approved soft treatment drawings.The sketch of retaining wall foundation and drainage ditch is presented in Figure 1. Figure 1 Sectional view for retaining wall foundation and drainage ditch5.4.2 C20 Concrete Foundation Construction of Reinforced Retaining wall Erect the concrete foundation formwork in accordace with the concurred drawing requirement. QIor QE will inspect the formwork erection ahead of pouring, and then could proceed to concreting. Loader will be adopted for C20 concrete foundation pouring (other suitable machine could be chosen as the actual situation as well), then poker vibrator will be used to make manually vibration. The concrete slump shall be controlled between 30-50mm.One group standard curing test cube shall be kept for each concreting shift. 2 additional expansion joints 10mm(wide)*6mm(deep) will be set on the foundation 15.6mm long in-between settlement joints to prevent crack.5.4.3 Foundation formwork stripping After completing C20 concrete foundation, the formwork could be removed under condition that the concrete strength is enough(4 hours) without harming the foundation surface and edges. 5.4.4 Laying and storage of blocksBefore laying of blocks, blocks shall be checked if they are qualified(standard dimension) or not,storage the qualified blocks at same location and separate the unqualified ones.Place further courses as per the concurred drawings ensuring they are pushed fully forward and are square with the previous course. Every course of blocks should be checked for horizontal and vertical alignment and the line and level of the wall overall checked every 3rd course. Any adjustment necessary may be made using ribs cut from the geogrid/cement motar or approved shims and trimming/grinding excess heights, placed in between blocks.5.4.5 Geogrid Placing and Face Installation（a）Cut the grid from the roll to achieve designed length as a minimum and cut to leave 50mm away from transverse bar (across the full width of the roll). Do not cut them back to the transverse bar.Refer to the Sketch as below.（b）Remove all debris from the top of the facing units using a brush.（c） Place the prepared end of the grid over the rebate in the block & locate the moulded connectors around the transverse bar. Ensure that each aperture of the geogrid is covered by a connector. The connectors should be split where necessary.（d）Position the assembly neatly into the rebate with the trimmed ribs towards the face.（e）Repeat this procedure for the whole course ensuring that adjacent lengths of grid are abutted at the wall face.（f）Once again, ensuring all debris is brushed away, place the next course (precast blocks are now used right up to the coping course). They should be placed stretcher bond & arranged so that the downstand is pushed up against the front of the rebate in the lower unit.The precast blocks will be cut by machine to maintain the strencher bond.（g）Installing of a settlement plate as per concurred SGT drawings.(h). Pull the grid so that the moulded grid connectors are up against the rear of the rebate.(i). Insert the tensioning beam(rebar or wooden rod) or other method of tesion beam through the apertures at the free end of the grid & apply a load sufficient to remove any slack.Refer to Figure 2, Figure 2 only for reference.The length for every section will be adopted in accordance with the concurred drawings.(j).The plumb bob will be used to control the wall tilt during the installation of the blocks.Figure 2 Layout of tension beam5.4.6 Filling and Compaction(a). Install a 400mm thickness of size 20-40mm crushed stone behind the face.A piece of geotextile will be used to cover the filler ( crushed stone) to prevent erosion, refer to Figure 3.Figure 3 Layout of geotextile (b) .Whilst maintaining tension, place a layer of fill on the grid which is sufficient to retain it in position when the load is released.Then release the tension & remove the beam.(c) .Fill should be placed by plant such as an excavator bucket or dozer with an opening bucket, which causes the fill to cascade onto the grids.Plant used to place fill should be kept at least 2m away from the face.Use a vibrating plate compactor or vibrating roller with a mass per meter width less than 1300kg and a total mass less than 1000kg within 2m of the face.(d) The geogrid will be folded over, then place and compact fill, keeping required courses above the fill until the top of the structure. Compaction should always commence nearest the facing units, working away toward the free end of the grid. Any lengths of grid fitted into the wall face above the level of fill should be temporarily folded over the top of the wall to provide a free working area.Refer to Table 2 for actual inspected items of area 1m inside to the wall, and the compaction degree of area under geogrid is required 96% ,other parts is required as same as the standard in subgrade compaction regulation.Actual Inspected Items of Rinforced Earth Retaing Wall Back Filling Table 2Item Inspection itemSpecified value or allowable deviationInspection method and frequency 1Compacrion degree of area 1m inside of wall (%)90One place at each segment compacted layer, and cannot be less than one. 21m outside of wall96Laboratory shall be informed by SE for compaction degree inspection, and QE or QI shall be there for witness and inspection.5.4.7 Drainpipe Location ConstructionThe holes will be made in the blocks,12 bars will be put inside of the holes,then the epoxy adhesivs will be used to fill the holes. The drain pipe shall be installed simultaneous with the blocks of the wall according to the construction drawings,refer to Figure 4. 5.4.8 Drain Ditch ConstructionDrain ditch shall be constructed as the concurred construction drawings. Figure 4 Detail actual configuration of blocks5.4.9 Collision Protection Wall Construction The variable height of longitudinal beam topping below the anti-crash barriers will be constructed section by section according to approved drawings and the actual height of every section of the retaining wall. Refer to Figure 5.The collision protection wall method will be separately prepared. 5.5 质量控制标准Inspection and Testing PlanQuality guarantee, hold point (H), witness point(W) refer to the Inspection and Testing Plan (Annexure 1)Process control shall be conducted by QI and witnessed by QE to ensure the construction quality of reinforced earth retaining wall reaches the requirements of drawing and specification. Figure 5 Construction for longitudinal beam topping详见JTG F80/12004第9章9.8.2节，表9.8.2：序号检查项目规定值或允许偏差检查频率(方法)1混凝土强度（Mpa）在合格标准内混凝土试验报告2高度(mm)+5，-10尺量：检查3个断面3宽度(mm)304顶板厚明涵+10，-0尺量：检查3-5个断面暗涵不小于设计值5侧墙和底板厚(mm)不小于设计值尺量：检查3-5个断面6平整度（）52m直尺：每10m检查2处3尺5.6 Reinforced Earth Retaining Wall Quality Control Standards Details refer to Section 6.4 Chapter 6 JTG F80/12004 Table: 6.4.2-1 Tendon (geogrid) Table 1Item Inspection itemRegulated value or the allowable deviationCheck method and frequency1Length of geogridNo less than the designRuler measure: check 5 pieces ( strands) every 20m2Joints of geogrids and blocksMeets the design requirementsVisual inspection: check 5 places every 20m3Geogrids pavingMeets the design requirementsVisual inspection: check 5 places every 20mDetails refer to Section 6.4 Chapter 6 JTG F80/12004 Table: 6.4.2-4 Blocks installation Table 2Item no.Inspection itemRegulated value or the allowable deviationCheck method and frequency1Design top elevation of blocks of every layer (mm)5Water level: spot check 3 sets of blocks every 20m2Displacement from horizontal alignment (mm)3Ceiling line, ruler measure: measure 3 places every 20m3Face vaticality (%)+0, -0.5%Ceiling vertical line: check 3 points every 20m6.0 Safety and Environment Management1) Safety management refers to Safety Management Plan2）Environment management refers to Environment Management Plan7.0 Quality Record Document/ResultNo.：QR012 Field Quality Inspection Report Sheet of Reinforced Retaining Wall Strand（geogrid）No.：QR014 Field Quality Inspection Report Sheet for Panel Installation of Reinforced Retaining WallNo.：QR016 Field Quality Inspection Report Sheet for Wall Back Filling WorksNo.：RQN50 Concrete Pouring Record Sheet Other records refer to MS-303E.8.0 AppendixAppendix 1：Reinforced Earth Retaining Wall Construction Inspection and Test PlanSri Lanka Colombo- Katunayake Expressway (CKE) ProjectField Quality Inspection Report Sheet of Reinforced Retaining Wall Strand（geogrid）Document No.： Table No.：QR012Works titleConstruction DateChainage and LocationInspection DateBasic requirementsItem No.Requested ContentsInspection Comments1Sub-clause 6.4.1.3 of JTG F80/1-2004 Strand （geogrid）quality and specification、quantity2Sub-clause 6.4.1.4 of JTG F80/1-2004 Strand （geogrid） installation requirementsMeasured ItemsItem NoInspection ItemsSpecified Value orAllowable DeviationInspection Results (Measured values)Remarks 1Length of strands（geogrid）Not less than design value2Connection bet