钻孔灌注桩方案英文.docx

1、钻孔灌注桩方案英文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 CONTENTS3.0 S

2、AFETY AND HEALTH.145.0 QUALITY ASSURANCE176.0 APPENDICES.181. TITLE Method 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 accessories and manpower to install the dr

3、illed 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 shall also be installed and tested in addition

4、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.2.2 Plant and EquipmentTo perform the necess

5、ary 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/devices page 1 of 18The number of the different

6、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 Material2.3.1 General materialThe materials need to complete a p

7、ile 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 directed by the Royal Commision.2.4 S

8、ite Planning & Preparation2.4.1 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 utilities.The internal traffic arrangemen

9、ts 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 activities at each location as indicated

10、 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. Coordination of works with other contr

11、actorsOther 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 to be taken.2.4.3 Methodologya. Pile D

12、esignThe 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 height of 1.00m above cut-off l

13、evel. 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 driving a steel pin as mark with

14、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 offset points shall be drawn in o

15、rthogonal 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 illustration photo below： Fixing o

16、f 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 order to support the overburden s

17、oil 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 than the pile shall be installed us

18、ing 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 hydraulic piling rig During driv

19、ing 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. Drilling to design depth and cleani

20、ng 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 be carried out using ground wate

21、r 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 drilling, it shall be ensured that

22、 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 as drilling proceeds. Bentonite

23、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/mlVISCOSITYMARSH CONE30 70 SECONDSLESS THAN 45

24、 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 operationDrilling of pile bore page 7 of

25、 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 removed during cleaning process.Cle

26、an 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 exercises. Cleaning of bore with flat

27、 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 25mm steel mesh and tied to the

28、 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 their design position by more th

29、an 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 from the piles to be embedded in

30、 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 scheduled within the reinforcing s

31、ubmittals.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 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 the tip