Study On Stability Of Fractured Rock Slope Under Rainfall

China has a vast territory and a wide distribution of mountains and rivers.With the development of science and technology and the improvement of social demand,the development and utilization of mountain area is deepening.With the construction of a large number of slope projects and the occurrence of a large number of landslide disasters,people pay more and more attention to the study of slope stability.Slope instability is the result of many factors,among which the influence of rainfall can not be ignored.In the fractured rock slope,the seepage and failure of the slope are mainly controlled by the structural plane.The percolation characteristics of fractured rock mass are determined by the characteristics of randomly distributed structural planes.Based on the statistical rock mechanics theory,this paper derives the calculation formula of the permeability coefficient of the whole space distribution and the equation of the infiltration line of the rock slope from the point of anisotropy.Using SMRM rock mass engineering parameter calculation system and slope stability analysis program based on unbalanced thrust method,the stability of fractured rock mass slope under rainfall is calculated and analyzed,and the related parameters are studied.The main results and conclusions are as follows:(1)the seepage characteristics and their genesis of fractured rock mass are introduced.The results show that the seepage characteristics interact with each other and are related to the nature and distribution of the structural plane in the rock mass.The anisotropy of fractured rock mass seepage is the most essential characteristic.(2)on the basis of statistical rock mechanics theory,the calculation formula of total spatial distribution permeability coefficient is derived,and the influence of slope stress field on seepage field under confining pressure is analyzed through the variation of gap width.The calculation program of permeability coefficient based on the above theory is introduced,and the influence of the parameters related to the structure plane on the permeability coefficient of the whole space distribution is studied.(3)the anisotropic permeability coefficient is used to analyze the percolation of Rain Water in the fractured rock slope,which shows that the permeability coefficient in the direction of infiltration and the permeability coefficient in the direction of hydraulic slope in the direction of hydraulic gradient play an important role in rainfall infiltration.There are differences in numerical value and action mechanism between them.The classical soakage line equation in groundwater dynamics is modified to make it suitable for calculating the groundwater level of fractured rock slope under the action of rainfall.(4)comparing with the limit equilibrium method of rigid body,it is found that the unbalanced thrust method basically meets the needs of the study of fractured rock slope.Through further study,it can be seen that the two algorithms of unbalanced thrust method have their own advantages and disadvantages,and can be used comprehensively according to the demand in practical engineering.(5)based on the equation of infiltration line of fractured rock mass slope,the program of stability analysis of fractured rock mass slope under rainfall action is compiled by C # language based on unbalanced thrust method,and its development idea is discussed.The core functions and usage methods are explained.(6)taking a rock slope near Shankouyan dam as an example,the reliability of wetting line equation of fractured rock slope and the validity of slope stability analysis program are verified.Taking the slope of Laoying Mountain opencast mine in Shaoxing as an example,according to the measured data of structural plane and geological exploration data,the stability of mine slope is analyzed by using self-compiled program.In addition,the influence of various parameters related to or affected by rainfall on the stability of rock slope is further studied.