钻孔灌注桩方案英文

1、METHOD STATEMENTChina Communications Construction Company Ltd.THE INSTALLATION OF PILESMethod Statement No: CCCC-SWC-MST-005Rev. #DescriptionNoted ByPrepared ByApproved By 00MST- the Installation of PilesHan YudaDCCMa YanfengQC ManagerXu ShangquanDeputy Project ManagerTABLE OF CONTENTS1.0TITLE 12.0S

2、COPE OF WORK13.0 SAFETY AND HEALTH.144.0ENVIRONMENTAL ISSUES 165.0 QUALITY ASSURANCE176.0 APPENDICES.181. TITLEMethod statement for the installation of piles.2. SCOPE OF WORK2.1 General DescriptionThe scope of works includes mobilization of piling equipment, drilling and concreting tools, mechanical

3、 accessories and manpower to install the drilled cast-in-place piles. Details of the drilled piles are given below. a. Pile Diameter: 1200mm.Pile Length: 18m Total nos.: 48.b. Pile Diameter: 1000mm.Pile Length: 18m Total nos.: 76.Two nos. preliminary test piles having 1000mm and 1200mm diameter shal

4、l also be installed and tested in addition to the above mentioned working piles. The location of the two test piles have been shown in this method statement ,and shall be discussed and agreed with RC Engineer. This method statement covers the general methodology for the installation of these piles.2

5、.2 Plant and EquipmentTo perform the necessary tasks, the following main equipments shall be available on site:a. Hydraulic Drilling Rigb. Crawler Crane 50T c. Excavator d. Prime movers and trailerse. Welding generatorsf. Drilling and concreting tools g. Coasterh. Light vehiclei. Lifting gears/devic

6、es page 1 of 18The number of the different types of equipment available on site will depend directly on the extent of work, and might vary during different phases of the subject task. Cranes and their respective operators certificates shall be available on site all the time.2.3 Material General mate

7、rialThe materials need to complete a pile listed below:a. Steel reinforcement cage with plastic spacers and fixing b. Concrete of approved mix Design c. Controlled slurryd. Disposal of excavated material shall be carried out as necessary to facilitate the works, meeting all legal requirement, and as

8、 directed by the Royal Commision.2.4 Site Planning & Preparation Site layout and the location of the test pilesThe test piles shall be installed in the following drawings: page 2 of 18Furthermore, the test piles shall be well disposed and make sure the test piles would not affect the around util

9、ities.The internal traffic arrangements will be made in consultation with HSE personnel as specified :Equipment will be parked at designated parking areas.2.4.2 Permits and coordinationa. Permits and certificates:We will obtain all necessary permits for the installation of piles and its relevant act

10、ivities at each location as indicated in method statement. All equipments shall have maintenance records. Records of these inspections, maintenance certificates and daily checklists will be available at site prior to start of work. A copy of these documents will be kept with equipment operators.b. C

11、oordination of works with other contractorsOther contractors will be provided with adequate traffic access adjacent to site areas highlighted earlier. In case of any conflict, the issue will be raised and discussed immediately with the responsible contractors representative for mitigation measures t

12、o be taken. Methodologya. Pile DesignThe pile design has been tackled based on the geotechnical recommendation. The pile details shall be submitted in shop drawings for RC approval before execution.b. Demarcation of Pile LocationsA working platform of the piling equipments shall be made with minimum

13、 height of 1.00m above cut-off level. Survey works establishing the pile location shall be done on the working platform. page 3of 18The step would involve careful site survey and demarcation of pile locations in accordance with approved IFC drawing. The center of the pile shall be fixed at site by d

14、riving a steel pin as mark with the length of approximately 200mm and 150mm of it shall be under the ground below the working platform level. At protruding steel, a red color identification ribbon shall be tied to top of the steel pin，as we can see in the above picture. Subsequently, two reference o

15、ffset points shall be drawn in orthogonal direction 2m from the center of the pile location for monitoring of pre-drilling holes. These orthogonal offsets shall be the reference also during the installation of casing. Fixing two references offset points and alignment of rock auger is shown in the il

16、lustration photo below： Fixing of two offset points Alignment of auger to pile center page 4 of 18After fixing two orthogonal offset points and alignment of the rock auger in the pile center, pre-drilling of the bore shall commence as shown in the photo below.c. Installation of Temporary Casing In o

17、rder to support the overburden soil from collapsing during the pile installation phase and in order to ensure that deviation of the pile position at the cut-off level is in line with the project specifications, a temporary steel casing approximately 3.0m long and having diameter slightly greater tha

18、n the pile shall be installed using a hydraulic piling rig. A casing adaptor shall be attached to the rotary driving head of the hydraulic piling rig and the temporary steel casing shall be driven through the soil at the designated position. page 5 of 18Installation of temporary steel casing with a

19、hydraulic piling rig During driving of the casing, a hand level and wooden frames extending from the reference control points shall be used to ensure that (a) the casing is driven vertically in each of the two orthogonal directions and the center of the casing is aligned with the pile center. d. Dri

20、lling to design depth and cleaning of pile base with cleaning bucketOnce the temporary steel casing has been installed up to the required level,drilling of the pile bore shall be undertaken using drilling bucket and drilling auger mounted on the piling rig. Drilling below the temporary casing shall

21、be carried out using ground water as drilling fluid or bentonite which ever suits the in-situ ground conditions. Trial bores shall be drilled using water as drilling fluid. In case some bore instability is observed using this system, drilling fluid shall be changed to the bentonite slurry. During dr

22、illing, it shall be ensured that the bore remains full of water or bentonite slurry to prevent collapse of the bore walls. In case of bentonite system, the bentonite shall be mixed and stored in steel tanks in accordance with the project specifications from where it shall be pumped to the pile bore

23、as drilling proceeds. Bentonite properties shall be controlled with in the specified limits given in Table-A. page 6 of 18TABLE- A.PROPERTY TO BE MONITOREDTESTING APPARATUSVALUES DURING DRILLINGVALUES PRIOR TO LOWERING OF STEEL CAGEDENSITYMUD BALANCELESS THAN 1.20 g/mlLESS THAN 1.10 g/mlVISCOSITYMAR

24、SH CONE30 70 SECONDSLESS THAN 45 SECONDSSAND CONTENTSAND CONTENT KITNO LIMITLESS THAN 6%pHpH Strips7 TO 127 TO 12The drilling process shall continue until the required depth is achieved as indicated in approved drawings. The picture below shows the hydraulic rig performing the pile drilling operatio

25、nDrilling of pile bore page 7 of 18Subsequently, the bore shall be cleaned with a flat bottom cleaning bucket (see photo below) to remove all loose materials deposited during the drilling operation. During cleaning, QC engineer and Piling In-charge shall monitor if there is no excessive material rem

26、oved during cleaning process.Clean the bore until that it is clear and without any loose materials around. Cleanliness of the bore can be felt during the sounding of the final depth. During pulling of measuring tape with weight at the end, it is moving freely and no resistance felt during such exerc

27、ises. Cleaning of bore with flat bottom bucketWith a graduated tape, the final depth of the bore will be measured after cleaning. The depths of the pile shall be measured from the top of the casing with known elevation down to the toe of the pile. After inspection, the casing shall be covered with a

28、 25mm steel mesh and tied to the casing hole to protect the worker from falling into the bore. Depth measurement is shown in the photo on the right side Sounding of final depth after cleaning page 8 of 18e. Tolerance of Pile PositionPile position at working platform shall not deviate laterally from

29、their design position by more than 75mm. Casing verticality shall not be more than 1:100 .f. Placement of Steel CagesReinforcing steel bars shall be deformed ,grade 60, and shall be assembled by steel fixer comply with the drawings. All reinforcing steeling to be embedded in the piles and extending

30、from the piles to be embedded in pile caps and other foundation elements shall be fusion bonded epoxy-coated. All spacer rollers, support bars, spreader bars, side form spacers, tie wire, and accessories necessary to hold the reinforcing bars securely and accurately in position shall be shown and sc

31、heduled within the reinforcing submittals.Once it has been verified that the bore has been drilled to the required depth and the bottom of the bore has been properly cleaned, steel cage fabricated according to approved shop drawings . Sufficient number of welded inner rings for rigidity and adequate

32、 concrete spacers for cover (all in accordance with approved shop drawings) shall subsequently be lowered into the bore. Once the reinforcement cage has been lowered, the cage shall be firmly hung from the temporary steel casing using steel wire rope such that there is a minimum 100mm gap between th

33、e tip of the steel reinforcement and the bottom of the excavated bore. page 9 of 18g. Concreting of BoresPrior to proceeding with concreting operation, the following procedure shall be addressed:Soil bund wall is mandatory to prepare to hold the displaced water/slurry from the bore and serves as sum

34、p pit to pump out the water/slurry towards water tank or water pond.Slurry discharge shall be done prior to connect the concrete pump pipe to concrete tremie head.The photos inserted below are the typical illustration of the soil bund wall to be constructed in every pile scheduled to cast. page 10 o

35、f 18 Excavator preparing for soil bund Bore ready for concreting with soil bund wallUpon placement of steel cage, tremie pipe and concrete pump tremie head at the top shall be lowered into the bore until it touches the tip level of bored hole. Tremie pipe (Ø200mm internal diameter, WT 7mm) shal

36、l be lowered in segment (12m length per segment) and secured with wire lock in the connection points. Concrete shall be pump through concrete pump tremie pipe head continuously until it flushes out the contaminated concrete (The tremie pipe shall be raised gradually (in accordance with concrete volu

37、me versus rise in depths) to make sure that the tip of the pipes imbedded at least minimum of 2m at sound concrete by using service crane.The volume of concrete being poured inside the pile shaft shall be closely monitored to determine if the rise of concrete against the volume being poured is meeti

38、ng the required quantity. Otherwise, the bore has cavity where some of the concrete volume flows and filled it. See the concreting operation below. page 11 of 18 Slurry discharge from the pump Fixing of concrete pump pipe to tremie headh. Bore WaterDuring the concreting of the bored hole, bore water

39、/slurry is displaced over the top of casing. It will be collected through small sump pit in the form of soil bund around the steel casing and pumped out by using diesel driven water pump. The ground water shall be pumped out towards adjacent water pond or water tank. page 12 of 18i. Cleaning Around

40、the Concreted PilesThereafter completion of pouring of drilled shaft, the contaminated concrete accumulated in the temporary soil bund shall be removed. Whatever mud resulted from the concreting of the shaft shall be scraped off. The collected contaminated concrete shall be stored in designated area

41、 at the site.2.5 Organization, Responsibility & Supervision2.5.1 Contractor Project ManagerResponsible for the overall execution of the project and ensure the full implementation of the work Safety Plan in accordance with the project specifications.2.5.2 Contractor Construction ManagerPlan, orga

42、nize, direct, control the execution of the work and evaluate the piles installation activities of the construction department under the direction of the Project Manager and ensure that all works are carried out as per project drawings and specifications. Responsible for assigning and giving correcti

43、on instructions to civil supervisors.2.5.3 Civil SupervisorsReporting Directly to Project Engineer .Ensure that all necessary permits are obtained prior to commencing the work. Responsible for supervising, monitoring and carrying out instructions and assigned tasks in the field and ensure that all w

44、ork are carried out by the respective civil foremen and its team true and correct as per project drawings and specifications.2.5.4 Civil QCResponsible for inspecting and testing to make sure all the material and works are according to the project specification and approved IFC drawing.2.5.5 Civil Fo

45、remen page 13 of 18Responsible in leading and undertaking the work together with his team of workers as per approved for construction drawings and specifications. Safety OfficerImplementing project safety procedure. Ensuring that workforce are aware and comply with safety requirements on site at all

46、 times and that all personnel have been brief on safety environment and emergency procedures. Ensuring that activities on site meet with the project HSE plan. Identifying accidents and near misses; and advising on preventive measures. Conducting toolbox talk about the work to be perform in site. Ens

47、uring that all equipment on site have valid third party certificates2.6 Work ForceThe competent and experienced piles installation Supervisor, Foreman, Equipment Operator, Surveyor, Watchman, Laborers will be engaged in these works to make sure the progress of construction satisfy the requirements.3

48、. SAFETY AND HEALTH3.1 Risk assessment Risks, at each stage are evaluated, utilizing the matrices inserted as to determine the level of significance in terms of likelihood of occurrence and severity of hazard based on the allocated numerical values. Job Safety Analysis included in Appendix 1.3.2 Spe

49、cific emergency proceduresFirst Aid kit will be provided on site at all times for light injuries.In the event of an emergency, all workers shall assemble at MUSTER POINT marked area and shall await further instructions from civil supervisor.Emergency number and respective site grid reference to be i

50、nstalled at site.3.3 Safety precautionsIn case of encountering unknown or hazardous materials, it shall inform immediately.Controlled movement of workers for near water working areas. page 14 of 18Life jackets to be worn on site at all times by all personnel working adjacent to water.Life buoys to be available at site. All equipment shall be ce