What is sand blasting backfill?

For the word "sand blasting backfill" or "sand blasting fill", some documents call it "sand blasting", "mud blowing" or "dredged fill", others call it "hydraulic sand blasting backfill" or "hydraulic flushing fill" and so on. Sand-blowing filling refers to the use of cement machinery to stir mud and sand, and through the pipeline laid in advance, the mud with a certain concentration is pumped to the surrounding areas where dredging and embankment filling are needed.

Hydraulic fill method: If the hydraulic fill area is far away from the borrow area, relay pumping method is usually adopted. According to different construction conditions, there are roughly three methods of hydraulic filling:

(1) When there is a stable sand source, you can directly use the cutter suction dredger (cutter suction dredger) to dig out the mud and sand at the bottom of the river, and transport the mud to the reclamation site through the pump on the dredger and the floating pipeline connecting the shore.

⑵ When there is an ideal sand source and a good working face, manual hydraulic flushing can be used, sand is washed and stirred into mud with a high-pressure water gun, and the mud pipe is sucked with a small mud pump. A pipeline shall be equipped with 15 ~ 20 hydraulic flushing device.

(3) When there is no fixed sand source, dredgers can be used to dig the mud and sand at the bottom of the river onto barges, add water and stir them, then transport them with mud pumps and dredge them to the project site. After dredging and filling, the silt flows slowly in the embankment, and the velocity gradually slows down. Near the sand outlet, the precipitated soil particles are coarse, and with the increase of slow flow distance, the precipitated soil particles gradually become fine. At the same time, a certain amount of fine soil particles suspended in the water, together with some water, are discharged into the drainage ditch outside the dike through the cofferdam. When the exposed dredger fill reaches the design elevation (the settlement of dredger fill and the settlement of the underlying layer should be considered), the whole dredger fill process is over.