THE STABILITY OF SOIL-ROCK MIXTURE SLOPES UNDER COMBINED EFFECTS OF RAINFALL AND TUNNEL EXCAVATION

Abstract

Because of their heterogeneous composition, soil-rock mixture (SRM) slopes respond strongly to both rainfall infiltration and tunnel excavation. In the model test, heavy rainfall was applied while two tunnels were excavated, and water content, deformation, and earth pressure were monitored continuously. Settlement accumulated rapidly at the beginning of the test as infiltration increased the soil mass weight and reduced shear strength. The subsequent increase became slower with further excavation. Lateral displacement, by contrast, showed a distinct sudden change before entering a period of gradual development. Earth pressure passed through three stages: relative stability, rapid change, and subsequent adjustment. The test results show that rainfall-induced weakening and excavation-related stress redistribution acted together to control the slope response, providing experimental support for stability assessment under similar conditions.