Study On Global Stability Of Double Slope With Soil And Whole And Strong Weathered Rock

There are few researches on the overall failure mode of the soil and rock double slope in China,and the overall stability failure mode of the soil and rock double slope has not been defined yet.Most of the practical projects complete such design according to the foundation pit specification,which is obviously different from the existing theoretical research and engineering cognition.In order to explore the global stability analysis method of soil and rock double slope in Jinan area,based on the research of the same research group under the same geological conditions,the failure modes under five different strata are summarized into three types.The theoretical and numerical analysis methods are adopted to obtain the following beneficial results,which can be used as reference for similar projects.(1)Based on the overall circular arc sliding mode of soil and fully weathered rock slope,the influence of slope rate and ratio of soil and rock layer on cracking point and safety factor on the top of slip plane slope was analyzed,and the fitting formula of cracking point location on the top of slip plane slope was proposed.The results show that the safety factor of the horizontal integration model is slightly lower than that of the vertical integration model,and the safety factor of the analytical solution is lower than that of the finite element method.Fixed the slope height,the thicker the soil,the more unstable the slope;The smaller the slope rate,the greater the safety factor.(2)in view of the small slope rate and strong weathering rock dual slope arc-plane overall failure mode,has been clear about the dual slope stability coefficient of soil and strong weathering rock analytical solution,and for the Swedish article points method need to specify the premise condition,the sliding surface jinan and strong weathering rock slope soil typical cases,use of slip line field method to derive the critical slip surface of slope,By analyzing the stress field of the slope with MATLAB software,the analytical solution of the critical slip line of the slope is obtained and the influencing factors of the critical slip line are analyzed.The results show that the safety factor of the horizontal integration model is slightly lower than that of the vertical integration model,and the analytic solution is less than that of the finite element method.The analytic solution is partial to safety.The finite element mesh size has little effect on the critical slip line,and changing the step size of the Matlab search program only has some effect on the slip line end,and has little effect on the overall shape of the critical slip line.(3)For the double-element slope of soil and strongly weathered rock whose slope rate is greater than the critical slope rate,the strongly weathered rock will be destroyed,and the failure mode is arc-plane-oblique plane failure mode.The excavation depth of 12-24 meters was selected to study the size of the strongly weathered rock failure body under different slope ratios.The results show that when the thickness of the strongly weathered rock exceeds half the height of the slope,the strongly weathered rock will be destroyed.The closer the slope rate is to the critical slope rate,the smaller the depth of failure body is.For the same slope height,the greater the thickness of strongly weathered rock is,the smaller the critical slope rate is.When the thickness ratio of strongly weathered rock is the same,the greater the excavation depth,the smaller the corresponding critical slope ratio is.