Study on the deformation mechanism of a fault-dominated creep-sliding and tension-fracturing slope in a dam site area

The deformation and stability of the dam slope are crucial for hydropower station safety during construction and operation. This study focuses on a near-dam creep-sliding and tension-fracturing slope at a hydropower station. Based on its engineering geological environment and deformation status, topography, geomorphology, rock mass features and the spatial distribution characteristics of key structural planes were systematically analyzed. Combined with monitoring data, the tracking of the controlling structural planes and structural zoning was analyzed. The creep mechanical properties of the area’s sandy slate were determined by a graded loading creep test, which verified the applicability of the constitutive model and provided reliable creep parameters for numerical simulation. Considering the main faults’ spatial combination and the weak plane effect, the spatio-temporal evolution characteristics of the fault-dominated deformation slope were revealed by a combination of field monitoring and three-dimensional numerical simulation. Furthermore, based on the sliding trend and distribution characteristics of the structural planes, a geomechanical model was established to explore the creep-sliding and tension-fracturing deformation mechanism. The results provide theoretical support for evaluating the stability of steep and high slopes of hydropower stations.