Study On The Failure Mechanism And Optimization Design Of Supporting For The Bedding Rock Slope With Weak Interlayer

The bedding rock slope with weak interlayer is one of the typical slope geological disasters,which has been an important engineering geological and geotechnical engineering problem of large-scale engineering activities such as construction engineering and traffic engineering in southwest China.Studying on the failure mechanism of the bedding rock slope with weak interlayer during excavation and construction,estimating its stability and proposing preventive and improving countermeasures systematically,have great significance for preventing and reducing geological disasters of basic construction project and can support the early warning,prevention and control of the serious geological disasters in southwest mountainous.Relying on the Guanjing Base slope,which is one of the large typical bedding rock slope weak interlayer in Guizhou Province,this paper studied the failure mechanism and rock-arch effect of the bedding rock slope with weak interlayer during excavation and construction by using some research methods such as laboratory tests,theoretical analysis and three-dimensional numerical simulation.This paper obtained the following several main achievements:(1)Based on engineering example,this paper summarized the storage environments,the characteristics of rock mass composition,rock mass structure and deformation failure of the typical bedding rock slope with weak interlayer in southwest mountainous.(2)Based on micro-failure theory of rock mass fracture mechanics,physical physical and mechanics parameters of slope rock mass are deduced.Experimental method of indoor rock mass and statistical method of field engineering geological survey are used to determine physical and mechanics parameters of slope rock mass.(3)Based on limit equilibrium method,this paper studied the back analysis of the shear strength of weak interlayer by using not only the single parameter method but slso the double-parameter method.(4)Three-dimensional numerical simulation models of bedding rock slope are simulated in this paper and the stressstate and displacement variation of slope after excavating have been calculated and analyzed by means of these models.This paper studied slip-compressing tensile failure mechanism of slope in the process of excavation.This paper also analyzed weak interlayer,rock strength and the rock mass on both right and left sides and their influence on the the slope stability.(5)This paper calculated the equations of rock arch axis,rise of rock arch and slope cut-induced influence zone by support-arching computing method.Based on software FLAC3 D,the arching conditions and characteristics after excavation are analyzed.(6)Based on soil-arching theory between piles and rock-arching theory,this paper analyzed the rational pile spacing and soil-arching effect between piles with different pile sections and pile space.