Abstract: To address the issue of poor waterproofing effect of grouting in pebble strata under high water level and flow conditions, indoor flow waterproofing tests were conducted to analyze the applicability of different grouting materials in pebble strata under high water head and flow conditions. The results showed that waterborne polyurethane had strong waterproofing ability and high water retention rate under high water head and flow conditions. In contrast, the waterproofing effect of cement-sodium silicate double liquid grout and fast-hardening sulfur aluminate cement grout was limited and the water retention rate was low under similar conditions. Based on this, a test section was set up in the foundation pit project of a metro station transfer hall in Beijing to verify the actual effect of grouting materials, the applicability of different construction techniques, and the parameters of grouting construction. And the overall grouting construction plan was adjusted according to the test results. During the project implementation, the excavation area was divided into zones through controlled grouting, which could further reduce the risk of excavation construction and ensure the smooth progress of foundation pit excavation operations.