【正文】 Apron Assembling reinforcement Formwork installation Method Statement of Underground Services System CHEC – SITV PROJECT MANAGEMENT OFFICE 13 of 79 Construction flow of waste water drainage system Preparations for construction Level Measurement and Payingoff Trench and pit Excavating、 leveling Bedding placing Culvert installation Manhole casting RC pipe marking and transportation RC pipe laying backfilling Acceptance of Quality SHOU 收 Water tank casting Assembling reinforcement Formwork installation Pipe and manhole and water tank testing and washing Method Statement of Underground Services System CHEC – SITV PROJECT MANAGEMENT OFFICE 14 of 79 Construction flow of electricity and munication system Preparations for construction Level Measurement and Payingoff Trench and pit excavating、 leveling UPVC pipe laying Cable trench casting UPVC pipe making and transportation backfilling Acceptance of Quality SHOU 收 Assembling reinforcement Formwork installation UPVC Pipe testing and washing Draw pit casting Method Statement of Underground Services System CHEC – SITV PROJECT MANAGEMENT OFFICE 15 of 79 Construction flow of water supply system and fire fighting system Preparations for construction Level Measurement and Payingoff Trench and pit Excavating、 leveling Galvanized steel pipe laying and fitting installation Galvanized steel pipe system testing washing Hydrant Manhole casting galvanized pipe marking and transportation backfilling Acceptance of Quality SHOU 收 Water tank casting Assembling reinforcement Formwork installation Bedding placing Hydrant intallation Pump installation Method Statement of Underground Services System CHEC – SITV PROJECT MANAGEMENT OFFICE 16 of 79 5 Drainage system ,sewage system, electricity and munication system Storm water drainage system, sewage drainage system and electricity and munication system mainly include construction work for pipe, drain, cable channel, manhole, oil interceptor and water tank. Reinforcement concrete pipe The diameter of this reinforced concrete pipe is 300mm to1800mm, and the length of each pipe is (not include the length of socket). Construction sequence Setting Out→Trench Excavation→Foundation Compaction →Foundation Acceptance→bedding Laying→Collar Installation→Pipe Installation→Pipe Test→fill the cement mortar and lay bituminous wood→Casting pipe support→lay the geotextile→Backfillin g Trench→Acceptance Setting Out Survey temporary bench mark on site according to drawing and bench mark appointed by engineer before excavation of foundation trench, the site temporary benchmark must be closed and the closure discrepancy ≤177。12 K mm (K is the distance between two benchmarks, unit : KM) , the temporary benchmark must be rechecked by engineer and then construction. Firstly, run a centerline and side line of pipe trench, stick the wooden pile and let out the lime line of excavation edge. Retest original ground level。 mark the excavated depth of pipe trench on a point at each 20m by bamboo pile. Trench excavation Excavation by the method of machinery and manual labor bined, the pacted sand and a small quantity of CMD column were used as excavation material. The depth of trench excavation is according to the design drawing. 1) slope of trench Method Statement of Underground Services System CHEC – SITV PROJECT MANAGEMENT OFFICE 17 of 79 Making the side slope of trench: Considering the effect of pipe installation by machine and dynamic load of temporarily stack tubing. When the trench depth is 1h , then trench slope shall be i = 1： ,(H:V). When the trench depth ≦ h2m, then trench slope shall be i= 1： ,(H:V). When the trench depth 2≦ h3m , then trench slope shall be I= 1： ,(H:V) 2) the width of trench The width of excavation for reinforced concrete pipe shall be according to (effective trench widths) in section 5 (drainage works) of contract specification. (Refer to table 01). Table 01 Nominal diameter of pipe （ mm） Effective trench width (mm) Nominal diameter of pipe （ mm） Effective trench width (mm) 100 550 1125 2200 150 600 1200 2300 225 700 1350 2450 300 750 1500 2600 375 1050 1650 2800 450 1150 1800 2950 525 1200 1950 3150 600 1350 2100 3350 675 1450 2250 3400 750 1500 2400 3500 825 1600 2550 3650 900 1900 2700 3800 975 2021 2850 3950 1050 2050 3000 4150 3) standard schematic drawing Method Statement of Underground Services System CHEC – SITV PROJECT MANAGEMENT OFFICE 18 of 79 Apron shall be set on slope surface for the slope stability and resisting the storm water in the rainy season . the standard schematic drawing of concrete pipe trench excavation is seen following Figure 01. 10.25~1:0.75un de rw at er pumpa pr ong ro un dc om p ac te d sa ndc o llarwa te rda mwa te rda m Figure 01 D1: diameter of pipe L1: effective trench width a1: trench width (300mm) b1: Work place on one side of concrete pipes ,b1=(L12a1D1)/2 4) slope protection and temporary drainage measures For preventing the water collected in overexcavation place and the low levelpipe trench,drainage measure shall be adopted in excavation ,and the drainage measure mainly includes trench drain and pumping drain. While construction, firstly, excavate the drainage trench of 300300mm on both sid