Raw water pipes.docVIP

Raw water pipes 2 at the edge of the water pump room to carry on (757 m) per trip D1420 x 14 steel pipe to pipe jacking construction. Water from riverbanks to using underwater laying head, two D1420 x 14 (10.95 m) long. Underwater pipe rack in five sets of DN1400 steel pipe pile supporting frame (spacing for 20 m). River the lowest water level of 0.09 m, and the average level of 4.07 m, the design flood level of 9.55 m, pipe top surface elevation of 2.1 m. Set in the middle of the water pump room and consideration of pipe jacking work well. During pipe jacking in place, should be in the dry season to take out the head, and avoid the Yangtze river water not influx from the pipe for water pump room. Pipe jacking in place after the big some should cross the Yangtze filling cement and sodium silicate mixture around the pipeline, to avoid the gaps between the Yangtze river water from the pipe and the soil through the Yangtze river levee, grouting pipe length not less than 40 m. Produce osmosis phenomenon in order to avoid the Yangtze river water along the pipe, in the face of the water here is within the scope of set pressure grouting impervious wall, 31.5 x 5 x 12 m (tube up and down in the 6 m, pipes, stretched out on each side the centerline of the lateral 10 m), 19 m within the diaphragm wall is apart from the top. Grouting technology requirements are as follows: Type double liquid slurry by using cement and sodium silicate mixture, strength grade 32.5 (R) fresh ordinary silicate cement, with 2% sodium silicate, 10% 30% fly ash. Serous initial setting time is 2 h, grouting amount, grout injection rate was 20%, the slurry pressure 0.63 1.5 MPa, water cement ratio is not less than 0.5. (according to actual). When the spacing of 1.0, grouting the outside first, after the internal way of grouting. Steel pipe concrete pile should penetrate the first (3) silt layer into the first 4 layer of coarse sand layer is not less than 1.0 m. Pipe supports of C25 underwater co