Study On Deformation And Failure Mechanism Of Rock Pile Slope Under Rainfall Condition

Rock piles are widely distributed in the southwest region,and the continuous construction of highway and railway projects inevitably passes through the rock pile section,which provides important engineering significance for the study of rock piles.Due to the development of internal voids,loose structure,and inconsistent material composition,the rock pile has the characteristics of discontinuity,heterogeneity and anisotropy.The deformation and failure mechanism of the rock pile is relatively complicated.However,it can be known from a large number of engineering examples that slip zones exist.A large number of fine particles indicates that the formation of slip zones is related to the migration and deposition of fine particles under the action of groundwater.This provides a new idea for the study of the deformation and failure mechanism of rock piles.Therefore,this paper adopts physical simulation tests for the particularity of the material structure of rock piles.Physical mechanics tests and numerical simulation methods,in-depth study of the deformation and failure mechanism of rock pile slopes under rainfall conditions.Through a large number of physical simulation tests,the fine particle migration and deposition rules and the characteristics of the sedimentary structure in the rock pile were obtained,and then the relationship between the sedimentary structure and the deformation and failure was obtained through physical and mechanical tests and numerical simulation analysis,and the edge of the rock pile under rainfall conditions was summarized The slope deformation and failure mechanism,finally taking the Hongyangou rock pile in Kaiyang County,Guizhou Province as a typical example,analyzing the characteristics of its sedimentary structure,to prove the reliability of the research.The main research results are as follows:(1)Under rainfall conditions,coarse-porosity rock piles are prone to form approximately arc-shaped basement deposits and arc-shaped relative water barriers,and fine-porosity rock piles are prone to form slope foot deposits and shallow surface deposits.The top is thin and the bottom is coarse.The shallow surface layer is deposited,the upper coarse layer and the lower fine type are mainly deposited on the contact surface of the coarse and fine layers.(2)The type of seepage deformation in the rock pile is mainly submerged corrosion.Submerged corrosion drives the fine particles to migrate down the shallow surface layer to the base of the slope and the outer arc of the rock pile,and a few migrate vertically downwards.(3)The coarse pore structure has a sedimentation limit and critical slope,and the fine pore structure has a critical sedimentation amount and critical slope for the conversion of seepage to runoff.The thicker the pore structure,the greater the permeability coefficient,and the more fine particles can migrate through latent corrosion.Deposit to the basement or the lower part where the permeability coefficient suddenly decreases to form a sedimentary zone.(4)Before the filling of fine particles,rainfall has little effect on the stability of the skeleton-type rock pile,but after a certain amount of fine particles is filled,a specific sedimentary structure-a relatively stagnant layer may be formed.As the rainfall progresses,the shear strength of this part is With continuous decrease,the osmotic pressure and pore pressure rise,and even excessive pore water pressure is formed,which causes deformation and failure of the fine-grained deposits.(5)By analyzing the transformation of fine particle migration and sedimentation on the rock pile and the relationship between the relative aquifer on the seepage field and deformation and failure,the deformation and failure mechanism of the rock pile is divided into shallow landslide mechanism and deep deformation and failure mechanism.Layer slumping is mainly for soil-like rock piles,and deep deformation and failure are mainly for rock-like rock piles.