Study on the damage mechanism of excavation in rocky foundation pit within steeply dipping structural plane

The self-stabilizing capacity of steeply dipping structural plane is the weakest in rocky foundation pit. This study proposes a geomechanical model tailored for examining the development of such structural plane. Utilizing sand, barit, gypsum, cement, and water, considering the crucial sand-barit and aggregate-binter ratio, 16 unique mix ratios are evaluated to analyze the physical and mechanical properties of analogous materials comprehensively. Through the analysis of three groups of rock foundation pits characterized by steeply dipping structural plane at inclination angles of 70°, 60°, and 50°, this study uncovers that the excavation process induces a stepwise increase in the surrounding strata's plane settlement. This phenomenon demonstrates notable characteristics of sudden and comprehensive slip destabilization. Building on these findings, the study advances a theory on unloading deformation damage for excavations in rocky foundations with steeply dipping structural plane. Such theoretical framework provides a basis for scientifically assessing the safety of deep rocky foundation pit excavations and for the rational design of supporting structures, thereby contributing significantly to the field of geotechnical engineering.