Numerical Analysis of Slope Stability Considering Grading and Seepage Prevention

The normal operation of Yulangpei tailings reservoir is affected by landslide stability. In this paper, taking the main and side slopes near the dam bank of the Yulangpei ditch as an example, water-soil coupling theory is applied to comprehensively evaluate the reliability of the side slopes of the tailings reservoir. Grading and seepage prevention (GSP) measures and the suction of the substrate are considered, as well as the infiltration of different rainfall and reservoir water levels. We numerically simulate the typical three forms of side slopes under the coupling conditions and conduct a reliable and comprehensive evaluation of tailings reservoir side slopes. The study shows that under six reservoir water level changes, the factor of safety (FS) of the bank slope shows a hysteresis effect. According to nine rainfall infiltration conditions and during rainfall, the greater the rainfall intensity, the greater the weakening effect. When rainfall stops, the FS rebounds. After GSP measures, the initial stability of the bank slope under different conditions is improved, but the main slope is more sensitive to changes in rainfall and water levels.

Study on Deformation Evolution Characteristics of Reverse-Dip Rock Slope under the Influence of Rainfall

In Southwestern China, there exists deep river valleys and abundant rainfall, which leads to a large number of reverse-dip rock slopes. In order to investigate the evolution characteristics of toppling deformation of reverse-dip slope under the influence of rainfall, and a typical reverse-dip slope was taken as an engineering case. Firstly, the temporal and spatial evolution nephogram of toppling displacement under different rainfall was obtained based on the discrete surface displacement monitoring data of bank slope. Then, taking bank slope, gully buffer zone, and development degree of bank slope as development characteristics based on geological field survey, afterward, the evolution characteristics in different strong deformation zones were analyzed by superimposing the development characteristic partition and the spatial and temporal displacement nephogram. The results showed that the horizontal displacement mainly occurred on the right front and middle rear of the bank slope while large vertical displacement occurred on the middle of the bank slope under the influence of rainfall. As the rainfall increased to the maximum, the toppling deformation reached the peak, and vertical displacement was more sensitive to the rainfall than horizontal displacement. After the superposition, the largest strong deformation zone was located in the middle and rear part of the bank slope, which is characterized by medium and high slope and mature stage and 50 m gully buffer zone. This paper explores the deformation and failure process of reverse-dip rock slope considering the change of rainfall through real displacement monitoring data and focuses on the real deformation evolution law of each characteristic zone combined with different development characteristics partition.

Landslide Accumulation Ice-Snow Melting for Thermo-Hydromechanical Coupling and Numerical Simulation

In this paper, we discussed the phase change coupling algorithm of accumulation bank slope under the action of ice-snow melting. We described the effect of temperature gradient on the water migration of soil. We simplified the stress balance, continuity, and energy equation in the coupled model. We discussed the variation law of temperature, seepage, and stress (deformation) field under different conditions of ice-snow melting on the bank slope of the accumulation body. Based on the three-field coupling energy balance equation of ice-snow melting with phase change, the simplified algorithm of three-field coupling is obtained. The simplified algorithm is applied to the coupling model of ice-snow thawing on indoor accumulation bank slope. We established a practical numerical model for the coupling analysis of temperature, seepage, and stress field. We established the coupled control differential equation of three fields. We investigated the three-dimensional numerical simulation of stress, displacement, plastic deformation, and other indicators. The results show that the numerical simulation results are in good agreement with the monitoring results. It is expected that the research results can more truly simulate the actual characteristics of ice and snow melting water on the bank slope of the Three Gorges Reservoir and provide reference for the prevention and prediction of extreme snow and ice disasters in the Three Gorges Reservoir area.

Failure mechanism and stability analysis of bank slope deformation under the synergistic effect of heavy rainfall and blasting vibration

Underwater drilling blasting technique is often adopted to clear away the obstructed reef and dredge-cut in the mountainous waterway dredging engineering. However, the vibration of the underwater blasting and excavation of the riverbed has a certain influence on the stability of bank slopes. Combined with the partial bank collapse phenomenon in the waterway regulation project between two dams in the Three Gorges reservoir area, the change of pore water pressure of unsaturated soil under heavy rainfall and the increase of permanent displacement of soil under blasting vibration in the reservoir area are discussed. This paper explains the weakening effect of rainfall infiltration and blasting vibration on the stability of the bank slope. By studying the law of slope failure deformation under the separate action and coupling action, it is found that rainfall infiltration promotes the increase of slope permanent displacement and the blasting vibration enlarges the infiltration area of the soil, which demonstrated the accelerated failure mechanism of the rainfall-blasting slope.