Study On The Failure Behavior Of Soil Arch Of Cantilever Pile Under The Action Of Earthquake And Rainfall

About two third of China's land is mountainous.With the development of economy,increasing number of railway and road projects are built in mountainous areas.For these projects,a large number of unstable slopes is the most prominent engineering problem.Due to the soil arch effect,anti-slide pile,as a kind of discontinuous retaining structure,still has a strong anti-slide ability and is widely used in slope support engineering.Soil arch,as an important prerequisite for anti-slide pile to play its retaining function,is liable to be damaged under the conditions of seismic force and rainfall due to its own bearing capacity limitation.Once the soil arch is destroyed,the whole anti-slide pile support project may fail.By means of theoretical analysis,laboratory model test and numerical simulation test,this thesis systematically studies the failure behavior of soil arch behind cantilever pile,deduces the strength calculation formula of soil arch behind pile,and verifies three typical failure modes of soil arch.The main contents and results are as follows:1)Firstly,the mechanical characteristics and mechanical relations of cantilever pile and soil arch behind pile are analyzed.Based on the analysis of pile-arch complex,the concept of bearing capacity of soil arch is put forward and the calculation method of ultimate bearing capacity of soil arch is derived.Based on the concept of soil arch bearing capacity,the concept of soil arch failure is put forward,and the typical forms of soil arch failure are analyzed.2)The dynamic response characteristics of pile-arch complex under seismic dynamic action are analyzed.According to the horizontal displacement of anti-slide pile and slope under different earthquake accelerations,the basic law of anti-slide pile deflection under earthquake dynamics is obtained.3)Aiming at the complex mechanism of soil arch failure caused by deflection of anti-slide pile,this thesis studies the deflection mode of anti-slide pile,proposes two basic deflection modes of anti-slide pile,designs model tests by ourselves,and studies the stability of soil arch under different deflection modes.4)Aiming at the failure of soil arch caused by rainfall weakening,the failure of soil arch under the condition of rainfall was studied by using the homemade simulated rainfall device to conduct the failure behavior of arch complex.