Study On The Catastrophe Process Simulation And Controlled Of Filled Slope Under Rainfall Condition

Fillslope landslides are one of the frequently encountered engineering geology problems in the construction of highways,railways,and airports in the Southwest.Because of its loose structure and large gaps,water is easy to infiltrate into the fill slopes,affecting the internal rock mass and lubricating and softening of rock and soil.The fillslope landslides induced by rainfall is particularly prominent,especially in the complex geological environment of southwestern mountainous regions.This paper takes the fill embankment of Section K1362 390 in Fengjie of Chongqing as the research object.Based on the field data collection,physical simulation method,discrete element method and finite element numerical simulation method are used to analyze the precipitating factors of catastrophe in Fengjie subgrade.This paper takes the fill embankment of Section K1362 390 in Fengjie of Chongqing as the research object.Based on the field data collection,physical simulation method,discrete element method and finite element numerical simulation method are used to analyze the precipitating factors and Failure Mechanism of catastrophe in Fengjie subgrade.The deformation and failure process of the fillslope is reproduced,and the prediction and analysis of the later damage and movement of the catastrophe are performed.Predicting and evaluating the measures and effects adopted for the deformation and destruction of each stage,it provides a certain theoretical basis for the prevention and control of such geological disasters.The results are as follows:(1)The geological environment conditions of the fill slope were identified.The study area was the middle low mountain landform.The trailing edge of the slope was a catchment landform,which provided the water source for the collection and infiltration of rainwater;the outcrop rock was mainly Patong Triassic mudstones and a small amount of marlstones are found in the Triassic.Mudstones have low rock strength and are easily disintegrated under the effect of water.The study area is dominated by folds and the fault structure is not developed.The groundwater in the fill slope is mainly pore water,and the fill groundwater is significantly affected by rainfall.(2)The intrinsic conditions of the deformation of the fill slope were ascertained.The construction of the fill subgrade was mainly concentrated in the rainy season.As the accumulation of packing and continuous heavy rainfall caused the clay in the stockyard and surrounding environment to accumulate on the fill into subgrade with rainwater;And during the construction period,there were two obvious such processes.The first time the clay was thin,the thickness was about 5 10 cm.The second time the clay was thicker,about 15 20 cm.The clay interlayer becomes the controlling factor of the deformation and failure of the fill subgrade under rain(3)A geological conceptual model of the slope of the roadfill subgrade was established.A similarity theory was used to establish a physical model with a similar ratio of 1:100.And the mechanical parameters of the gravel soil and clay were obtained through various tests;the permeability coefficient of gravel soil is 0.017cm/s with a good fit.The cohesive force C is 33.27 and the cohesive force is 32.2° under natural conditions.the clay sensitibe to water,and the natural water content content rises from 15.11% to 20.42%,The mechanical parameters show a sharp drop,the cohesion force decreases from 39.45 Kpa to 17.47 Kpa,and the internal friction angle decreases from 15.52° to 5.9°,this provides the conditions for the clay sandwich softening to form a potential sliding surface under rainfall.(4)The characteristics of the entire process of the deformation and failure of the fill slope are presented.The phenomenon of deformation and failure under the condition of rainfall is simulated by the physical simulation experiment,and the whole process of deformation and failure of this type of landslide is roughly reproduced.According to the analysis of the test results,the whole process of the landslide can be divided into four stages: the surface creep stage,The trailing edge crack stage,the slope body down fault and the front edge bulging stage,and the potential sliding surface formation stage.According to the test results,this type of landfill landslide is mainly induced by continuous strong rainfall and collection rain infiltration,which causes the internal clay to soften and the strength to drop steeply.The weak zone becomes a potential sliding surface of the slope.(5)The process of fill slope catastrophe is simulated by PFC particle discrete element,and the process of the catastrophe process is deformed and destroyed,The numerical simulation of the deformation and failure process and mechanism of the slope According to the motion displacement and the movement rate of the landslide to divide the stages.The deformation and failure process and mechanism of the slope are vertificated by numerical simulation of PFC particle discrete element.Based on the physical simulation results,the finite element analysis of the characteristics of each stage of the seepage,stress and strain characteristics and stability,the process of fill slope catastrophe is analyzed.Then analyze the control effect achieved by the corresponding control measures at each stage by the finite element method,the necessity and effectiveness of the process simulation analysis on the fill slope catastrophe are verified.