Mechanical characteristics and application of cement-soil wrapped pile support structures for soil-rock combination pit in coastal area

In order to explore the mechanical properties of cement-soil wrapped pile support system in soil-rock combination foundation pit support. In this paper, based on a deep foundation pit project in Qingdao, the horizontal displacement monitoring test of cement-soil wrapped pile support system was carried out. Combined with ABAQUS finite element numerical simulation, the foundation support model of cement-soil wrapped pile in soil-rock combination foundation was established. The variation rule of bending moment and displacement of cement-soil wrapped pile under different influencing factors is explored, And the reasonable position of the micro steel pipe piles in the cement-soil pile is clarified. The results of the study show that the micro steel pipe piles have the best support with less horizontal displacement when they are located on the excavation side of the foundation pit. With the gradual increase of excavation depth, the horizontal stress of the soil basically increases linearly, which is consistent with the change rule of active soil pressure along the depth direction. Increasing the strength of cement-soil can significantly improve the deformation resistance of the supporting structure. The research results can provide reference for the design and construction of foundation support for soil-rock combination foundations.