Research On Stability Mechanism Of Soil Cave And Influencing Factors Of Arch Height In Karst Area Based On Soil Arching Effect

In recent years,karst collapse caused by soil cave has seriously threatened the safety of people’s property,which is very common in southwest and East China.The mechanism of soil cave stability and influencing factors of arch height in karst area is one of the technical problems that need to be solved in karst area at home and abroad.There are many influencing factors of soil cave stability and they are interrelated.At present,the mechanism and influencing factors of soil cave stability are still in the exploration stage.Therefore,it is necessary to carry out more in-depth research on this subject.In this paper,through the case of soil cave collapse caused by instability,the scale model test and numerical simulation model are designed to analyze the load sharing and soil arch height,clarify the stability mechanism of soil cave,and evaluate the influence of relevant factors on soil arch height.(1)In the process of soil collapse,soil arching will occur,resulting in soil arching effect.Due to the different stress of soil particles in the process of downward collapse,the soil will produce uneven displacement.Under the effect of soil arching,the pressure above the soil arching will be transferred to the surrounding stable area,resulting in the change of stress in the stable area.This provides a reference for the study of soil cave stability mechanism in this paper It provides theoretical basis.(2)In this paper,through the indoor scale simulation test,the load sharing and soil displacement in the stable area / collapse area are analyzed.During the test,the load sharing change law in the stable area / collapse area during the collapse process is observed by the pressure sensor,and the mechanism of soil arch effect on the stability of soil cave is clarified.The arch height is the most critical factor to measure the stability of soil cave from the perspective of soil displacement IV observe the change law of arch height and summarize the influence of different influencing factors on arch height.(3)Through the finite element numerical simulation software plaxis3d,the load sharing law of the stable area / collapse area is analyzed,and the stability mechanism of the soil cavity is revealed.At the same time,compared with the load sharing results of the scale model,the correctness of the soil arch effect on the stability of the soil cavity is verified.The numerical simulation software continues to analyze the different collapse width and filling height The influence of two kinds of different control conditions on the load distribution in the stable area / collapse area is obtained by numerical simulation.(4)Through the analysis of soil displacement,it can be seen that the soil above the arch is stable,and the soil below the arch is unstable.Therefore,the arch height is the most critical factor to measure the stability of the soil cave from the perspective of soil displacement.Six kinds of influencing factors such as different collapse width,fill height,cohesion,internal friction angle,top load size and location are set up through plaxis3d The law of influence on arch height is obtained.