Engineering Application of New Suspended Diaphragm Wall (Pile) Technology of Soil and Rock Dualistic Foundation Pit

In order to provide sufficient end embedment for the enclosure structure, rock shoulders and prestressed footing anchor cables are set at the bottom of the traditional suspended diaphragm wall (pile). A new type of supporting structure of non-rock shoulders suspended diaphragm wall (pile) is studied. Based on practical engineering, the design schemes of non-rock shoulder suspended pile, non-rock shoulder long and short suspended pile and non-rock shoulder suspended diaphragm wall are introduced, respectively. The excavation deformation characteristics of three supporting forms were studied by three-dimensional numerical model, and compared with the field monitoring data. The results show that the new supporting form of suspended diaphragm wall (pile) without rock shoulder and prestressed anchor cable can ensure the stability of supporting section through internal support and stilted structure. According to the rock strength and integrity of the visible bedrock, flexible choice of moderately weathered, slightly weathered rock as the footing structure bearing layer, and combined with grouting, anchor spray support and other measures to control the quality of rock wall excavation to ensure the stability of rock wall section. The excavation of the lower rock wall section has little effect on the internal force, deformation and land subsidence of the upper supporting structure, which can be ignored. Numerical simulation and field practice show that the three supporting methods can ensure the stability of the foundation pit and rock wall.