Numerical Investigation On Time-dependent Deformation And Failure Characteristics Of Jointed Rock Slopes

Triggered by temperature, alternating wet and dry, human activities and other external factors, the rock slope which contains weak layers and structure planes, its intrinsic physical and mechanical properties of materials are vulnerable to deterioration, especially its strength characteristics are significantly degraded with time, mesoscopic damage accumulate inside the rock, contributing the rock slope with weak structure planes generate the time-dependent deformation, and eventually lead to the slope instability and failure.Based on the knowledge of rheological characteristics of rocks, the strength degradation model is employed in the representative volume element and achieved in finite element program-RFPA software, to study the time-dependent deformation and failure of slopes in view of physical essence that the mechanical properties of rock are degraded and meso-scopic damage accumulation with time due to the influence of environmental variation.First, the time-dependent deformation and failure of slopes with weak structural planes distributed along the slope surface is simulated, slope containing a pair of under-lapping joints and over-lapping joints, slope containing three under-lapping joints and over-lapping joints, and slope containing one parallel joint set and two joint sets are systemetically constructed and investigated. The influence of spatial distribution and strength degradation characteristic of weak structural planes on the long-term stability of slopes is numerically investigated.Given the time-dependent deformation and failure of the rock, then the investigation is conducted from the occurrences of structure planes inside the slope, slope height and inclination and the characteristics of strength deterioration respectively, to study the long-term time-dependent deformation, damage initiation and evolution mode. The simulation and the analysis of results are expected to improve the understanding of the influencing factors of the slope, the evaluation of the long-term slope stability and its failure mechanism.Last, the influence of spatial distribution and strength degradation characteristic of weak structural planes on the long-term stability of slopes is numerically investigated. Then the time-dependent failure of an existed slope with weak structural planes and alternatively distributed soft and hard rock layers is numerically investigated. Due to the rheological characteristics of rocks, the strength characteristics are degraded with time and the slopes become more unstable. The long-term strength of weak structural planes and weak rocks plays an important role in the stability of rock slopes. The key factors such as long-term strength, seepage control, and excavation-induced unloading, etc., should be strongly considered in the optimum design of slope related to safety of stabilization. The results obtained in this study may provide a meaningful guidance for the design and construction of other similar slope engineerings.