Study On The Mechanism Of Rainstorm Instability And The Soil Arching Effect Of A Phyllite Accumulation In Wen-ma Highway

There are multiple developed phyllite accumulations endangering the safety along Wenchuan-MaErkang Highway,which are large porosity ratio and strong water permeability.Atmospheric rainfall is an important factor in such slope failure,especially continuous high intensity rainfall.Presently,studies on the orientation characteristics of the phyllite in the slopes of the phyllite accumulation are few,so are the stability analysis.Anti-slide pile is one of the most common slope control measures.The effect of horizontal soil arching,which is widely recognized by many scholars,is mainly used in the determination of pile spacing;but the application of its force distribution calculation in anti-slide pile is less,especially in the consolidation of the round pile.This paper,based on the phyllite accumulations slope on the left side of the K54+487?K55+417.of Wen-ma Highway,analyzes the rainstorm instability mechanism of such kind slope and the analytical method of the soil arching effect in composite slope structure.The main work is as follows:(1)Studying the structure,geological structure and mineral composition of phyllite by thin film identification and X-ray powder diffraction experiment.(2)Doing simulate experiments on the orientation of the phyllite accumulation carried out from the engineering site.And it is considered that the microstructures are developed due to the structural development of the microstructures,which is not conducive to the stability of the slope;(3)Analyzing the effect of rainfall infiltration on the shear strength of the phyllite accumulation is analyzed and studied by using the large-scale coarse-grain direct shear test.(4)Analyzing the steady-state characteristics and the transient characteristics of the slope after rainstorm for 12h and 24h with Midas-GTS-NX software,and summarizing the distribution characteristics and trend of pore water pressure and volume water content.The impact of the impact of the slope that is the main factors of instability occurred.(5)The stability analysis of the slope is carried out by using the transfer coefficient method.The FLAC3D software is used to simulate the shape and arch height of the arch of the circular anti-slide pile.Then put forward the mechanical analysis method of the pile and it's compared with the traditional design method.