Study On Evaluation Method Of Stability Of Red Clay Slope Under Dry-Wet Cycle

The degradation of the mechanical properties of red clay and the evolution of cracks in the dry and wet circulation make the slope failure of the red clay different from the traditional slide.The traditional slope stability calculation method is not suitable for red clay slope,and the failure mechanism of red clay slope is not clear,In view of this phenomenon,this paper takes soil mechanics as the theoretical basis and adopts field investigation,indoor model test,numerical simulation,mechanical calculation and image processing technology,etc.The main research contents include :The crack growth law of red clay slope during wet and dry cycle;Numerical simulation software is used to simulate the influence of the dry-wet cycle? the tensile crack and horizontal thrust on the slope stability.Study on the evaluation method of red clay based on shallow damage.The main conclusions of this study are as follows:(1)The width,depth and crack rate of the cracks increase first and then gradually stabilize with the development of cycles;the total number of cracks,the number of soil blocks and the total length of fractures reached the maximum value after the first wet-dry cycle,they all have different degrees of reduction in the second cycle,and then the total number of fractures tended to be stable.However,the total length of cracks and the number of soil block increase after the latter cycle.(2)Slope failure is related to grade.When the grade is small,the slope only has the crack development;As the grade increases,the slope surface appears shallow,partial,progressive destruction,and the failure of the surface is shallow fold line;When the grade continues to increase,the surface of the slope appears to be unevenly detached,without obvious failure surface.(3)Through the study of the strength of slope layered characterization of dry-wet circulation role,The stability of slope decreases with the increase of dry and wet cycle;potential sliding surface of slope from the depths of the slope to the slope play area,and shape of slip surface by arc shape into a shallow line or lines arc compound sliding surface,it is more consistent with the actual destruction of red clay.(4)The slope stability decreases with the increase of the depth of the tensile crack in the slope,and the failure mode is changed from the shallow surface damage of slope to the local slump of the slope.The stability of the slope is not affected by the width of tensile crack;the slope stability decreases with the increase of horizontal thrust.(5)The stability of the slope decreases with the increase of the crack rate,and the failure zone is changed from the shallow to the topical damage.The stability of slope decreases with the increase of crack depth.(6)According to the actual damage form of the red clay slope,two stability evaluation methods are proposed for line sliding surface and the composite slip surface.and the calculation result is lower that of simplified Bishop method,which is in line with the actual situation of red clay.Through this article research has been clear about the red clay slope fracture law under the dry-wet circulation,it is concluded that the dry-wet circulation role,top tension fractures and horizontal thrust,red clay slope failure mechanism under the dry-wet circulation,red clay slope stability calculation method is put forward under the dry-wet circulation.The research results provide more perfect technical support for the design and maintenance of red clay slope,which is of great academic significance and engineering application value.