| Lanzhou is China's geographical center.The topography of the two mountains in the north and the south is undulating,the loess and the gully stretch,the vegetation is scarce,the precipitation concentrates.Loess landslides occur from time to time under the influence of rainfall and earthquakes,which seriously threatens the lives and property of local residents.Therefore,it is of great significance to study the stability of local landslides.This article focuses on the study of landslide which is located on the southern slope of Lanzhou City,both of which are loess landslides.In this paper,the SEEP/W module and SLOPE/W module in Geostudio software are used to simulate the landslide.The work and results of this paper are as follows:?1?The average saturation permeability coefficient of loess was 9.08×10-4cm/s as measured by field experiments.The predecessor test data and soil particle grading in Lanzhou were collected to obtain the unsaturated permeability coefficient curve of loess.?2?The simulation results of the seepage field of landslide No.I indicated that the thickness of the transient saturation zone at the same location after rainfall in the five rainfall conditions was 3m,4m,4.6m,5m,and 5.5m,respectively,and the stabilization time was 20 min,40 min,12hr,and 25hr,it can be seen that the effect of prolonged light rain on the seepage field in the slope is much greater than that of the short-term heavy rain and the influence of rainfall infiltration is delayed.The saturated permeability coefficient of the loess layer is 0.55mm/min.When the rainfall intensity is smaller than the infiltration coefficient,the greater the rain intensity,the faster the infiltration.The simulation results of the seepage field of the No.II slope also have the above characteristics.After rainfall,the pore water pressure and volumetric water content of the slope increase,and the matrix suction decreases continuously.?3?The stability analysis of No.1 Landslide shows that the safety factor is less than 1 under natural conditions,rainfall conditions and earthquake conditions.The landslide is in an unstable state,which is consistent with the actual investigation,that is,the landslide is unstable.Therefore,the Geostudio analysis software is reasonable for evaluating the slope stability.To a certain extent,it can have a relatively accurate analysis of the slope.The safety factor of Hongshangen II slope is equal to 1.05 under natural conditions.The slope is in a basically stable state.When the rainfall is met,the safety factor is less than 1.05,and the slope is in a state of under stability.The safety factor is equal to 0.9 in an unstable state under seismic conditions.?4?After the comprehensive reinforcement design of anchor cable and anti-sliding piles for Hongshangen II slope,the safety factor increased to 1.25,and the slope was in a stable state.This design proposal has reference value for the reinforcement and treatment of the slope in the later period. |
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