Research On Destabilization Mechanism And Landslide Volume Prediction Of Slopes Containing Soft Inclusions Under The Action Of Rainfall

Sliding damage of rocky slopes with weak inclusions is very likely to occur under the action of heavy rainfall,and scholars have mostly investigated the destabilization mechanism through numerical simulation tests in the past.In contrast,there are relatively few real-world studies using similar physical model tests,and the influence factors considered in the existing studies are relatively single.To address this situation,this thesis integrates indoor model experiments,computer vision techniques and theoretical analysis to firstly build a physical model of rocky slopes with different soft and weak inclusions and conduct indoor rainfall tests.Secondly,by analyzing the influence of different weak and soft interlayer forms on the infiltration law of rainfall and the destabilization process of slopes,the destabilization mechanism of rocky slopes with weak and soft interlayer under the rainfall is revealed.At the same time,the two-dimensional area and three-dimensional volume of the rocky slope deformation zone during the six groups of landslide experiments are analyzed by the spatiotemporal hybrid calculation,which further reveals the spatiotemporal damage law of the rocky slope with weak inclusions under the rainfall action.Finally,in order to accurately assess the landslide hazard and provide more information for landslide disaster emergency rescue,this thesis proposes an S-growth curve model for predicting landslide volume.The details and findings of the study are as follows:(1)Six groups of model tests A1(homogeneous slope),A2(weak interlayer inclination of45°),A3(weak interlayer inclination of 35°),A4(weak interlayer inclination of 35°,spatial position of 15cm downward),A5(weak interlayer thickness of 7.5cm)and A6(weak interlayer thickness of5cm)are established to study in depth the spatial position,thickness and inclination of the weak interlayer on the slope damage pattern and infiltration pattern.The results show that under the action of rainfall,the slope mainly shows two kinds of damage patterns,one is erosion damage and the other is block damage.Experiment A1 has shallow erosion damage,experiments A2 and A3 have more obvious erosion ditch and deeper damage,experiment A4 has only small-scale shallow erosion damage at the foot of the slope,A5 and A6 have damage in the mode of stage sliding block,and the damage degree is larger.It is relatively difficult for rainwater to infiltrate into the rock,and when the upper end of the weak interlayer is adjacent to the hollow,it will be easier for rainwater to infiltrate into the weak interlayer,and the soil moisture sensor and pore water pressure sensor values in the weak interlayer produce changes more quickly.The water content changes generally show the phenomenon of increasing first and then stabilizing,and after stabilizing,the water content at the bottom of the slope is higher than that at the top of the slope.(2)Based on image recognition technology,quantitatively calculate the two-dimensional area and three-dimensional volume of the landslide deformation area,and conduct a joint analysis of the calculation results with time and space.It is found that the shape of the weak interlayer in the slope is different,and the time when the slope begins to fail and the failure tends to stabilize is different.The failure volume of a homogeneous slope under rainfall is the smallest,0.0059 m~3.The final failure volumes of other rock slopes A2,A3,A4,A5,and A6 containing weak intercalations are 0.0388 m~3,0.0597 m~3,0.01326 m~3,0.096 m~3,and 0.0592 m~3,respectively.The lower the spatial position of the weak intercalations,the smaller the thickness,and the more stable the slope.When the dip angle of the weak intercalation changes and the slope changes from bedding slope to cutting slope,the degree of slope damage increases.(3)The damage process of landslide goes through three stages,which are pre-slip stage,sliding damage stage and stabilization stage.In the quantitative identification curve of landslide,the landslide volume change has a certain time lag relative to the area change,and the landslide volume continues to increase after the landslide area damage tends to stabilize.(4)An improved S-growth curve model with two landslide volumes at an interval of 5 min and the influence factor(i)of the final damage volume of the landslide as input is proposed to accurately predict the volume of the landslide at the next moment.Validated by six sets of experimental results of the model,the error(MAPE)results of the S-growth curve in predicting landslide volumes ranged from 2.62%to 5.99%,which was more accurate than the time series analysis-moving average model.