The Research On Physical Model Experiment Of The Load-unload Response Ratio Pattern And Its Failure Mechanism Of Debris Landslide Induced By Rainfall

Debris landslides are the mainly geological disaster in the Three Gorges Region, accounting for 64%of the whole regions landslide,and majority are induced by rainfall and groundwater.Therefore makes clearly the failure mechanism of the debris landslides induced by rainfall and unify the landslide prediction and forecast theory to make the effective forecast fore debris landslides has the vital significance.Selecting the debris landslides in the Three Gorges reservoir region as the research background,supported by projects of the National Natural Science Foundation of China "Load-unload responding ratio parameter and displacement dynamic prediction(code No.40672182)",in the foundation of system investigation and research of the debris landslides in the Three Gorges reservoir region,establish indoor model experiment, make the failure mechanism research of the,and also analysis the relation between the pattern of the load/unload response ratio and stability of the debris landslide induced by rainfall,some results are summarized as follows.1.Systems analysis investigated and studied the shape essential and geological condition and its material constitution characteristic of the debris landslide in the Three Gorges region,make subsection research fore the debris landslide of the Three Gorges region,and also analysis the debris landslide basic characteristic and dynamics characteristic.2.Discussed the possibility fore taking the groundwater level as the load/unload parameter of the debris landslide,determined the load/unload parameter and response parameter and its load/unload response ratio,established the load/unload response ratio prediction model of taking the groundwater level as the load/unload parameter.3.Inferred the physical model experiment similarity parameter of the debris landslide induced by rainfall,established the debris landslide physical model,used the indoor large landslide model experiment equipment,the debris slope destroyed experiment was carried through under different rainfall conditions,and made analysis the changing characteristic of groundwater level and slope distortion in the destroy process of the debris landslide induced by rainfall.4.The main failure mechanism of debris landslides induced by rainfall was that in the process of rainfall seeped and the groundwater evacuated,the seep and drainage channels was formed,and the indoor substance structure of the slope is changed,the granule increased in front edge of the slope and went against the groundwater evacuate,the cracks formed with The slope distortion which increased the rainfall seep,so when the rainfall intensity was large,the groundwater level in front edge of the slope increased quickly with not evacuate easily,which largely reduced the stability of the slope,and the front edge of the slope would be destroyed firstly,followed the whole slope was destroyed5.Union the failure mechanism of debris landslides induced by rainfall,analysis the relation between the response ratio parameter of taking the groundwater level as the load/unload and the slope distortion as the response and the slope stability,found the groundwater level is the main effect of changing the slope stability,and the displacement reflected the evolvement trend of the slope stability,so the load/unload response ratio that union the groundwater level and displacement would effective the slope stability condition.6.The load/unload response ratio in the destroyed process of the debris landslide gradually increased with the reduced of the slope stability.When the slope stability was reduced,the load/unload response ratio would increased.When the slope in stability in steady stage,the load-unload response ratio was 1 or fluctuated near 1,but when the slope was in un-stable stage and was destroyed,the load-unload response ratio would break and is far off bigger than 1.