When conventional grout is injected in thick waterrich sandy gravel strata, problems, such as grout loss in strata and uneven diffusion of grout, will occur, which will weaken the waterproof effect greatly and cannot guarantee the grouting effect. In the paper, a series of grout mixing tests are conducted in the laboratory, and model tests and field tests are made on the grouting for sandy gravel strata, based on the geological characteristics of the thick waterrich sandy gravel strata. Conclusions drawn are as follows: two new grouts, i.e., CDSCA grout and PCSCA grout，are suitable for thick waterrich sandy gravel strata. When these grouts are injected, they spread evenly in columnar diffusion, the diffusion radius can meet the design requirements, the penetration of the grouts are improved significantly, and the watersealing requirements of the waterproof curtain wall are satisfied. The paper can provide reference for the grouting in similar strata in the future.