| Clay-rock mixtures are two-phase mixed materials composed of low-strength clay and high-strength rocks.They are not only widely distributed in nature,but also greatly utilized in engineering.At present,the research on the dynamic characteristics of soil-rock mixtures mainly focused on sand-rock mixtures,but few related to clay-rock mixtures,which can not guide the engineering application well.Therefore,it is necessary to systematically study the dynamic characteristics of clay-rock mixtures.The clay-rock slope is composed of clay-rock mixtures and widely distributed in the central and western regions of China.The clay-rock slope shows different response characteristics from the homogeneous soil slope under dynamic loading,but there are few studies on the response characteristics about this.Therefore,it is necessary to study the dynamic response characteristics of clay-rock slopes.In this paper,the resonant column of GZZ-50 type was utilized to test the dynamic shear modulus and damping ratio of clay-rock mixtures,and the corresponding results were explained with microscopic analysis.Based on these,studying the response characteristic of clay-rock slopes with programming and numerical analyzing,and the concrete contents were shown in following:(1)Measuring the experimental materials and improving the resonant column of GZZ-50 type that adding some new testing devices.Measuring includes: gravity,liquid plastic limit,optimum moisture content and expansion ratio of clay,and shape and gradation characteristics of gravels.Improving of resonant column includes: addition of laser displacement sensor which can measure the height of the sample in anytime,addition of hoop with a pin which can measure the soft soil that can not stand by itself,addition of current loading mode of the electromagnetic coil that can produce lateral vibration of samples.Based on lateral vibration frequency of samples and bending vibration equation,the dynamic elastic modulus of samples can be measured,which can be transformed to dynamic shear modulus too.(Chapter two)(2)Measuring the dynamic shear modulus and damping ratio of clay-rock mixtures with different rock content,gravel shapes,gravel sizes and confining pressures,whose results were explained with microscopic analysis,and 4 main typical destruction models were put forward.The specific contents include that the maxi dynamic shear modulus and referent shear strain of clay-rock mixtures increase with the addition of rock content,and the maxi and mini damping ratio reduce with the addition of rock content.All of these were related to rock skeleton statement including rock-floating skeleton,rock-parting skeleton and rock-completing skeleton.Clay-rock mixtures with round rocks had greater the maxi dynamic shear modulus and the maxi damping ratio than those with angular rocks that had greater referent shear strain,and it can also be obtained that rock shape had less influence on the mini damping ratio.All of these were related to the force transfer characteristics,compactness characteristic and constraint effect of the rock edges from the internal particles of the sample.Size effect of rocks in clay-rock mixtures were as follows.In terms of maxi dynamic shear modulus,relative size 1(0.05~0.2)> relative size 3(0.1~0.15)> relative size 2(0.05~0.1)> relative size 4(0.15~0.2).In terms of referent shear strain,relative size 1> relative size 3> relative size 2> relative size 4.In terms of mini damping ratio,relative size 1<relative size 3< relative size 2<relative size 4.In terms of maxi damping ratio,relative size 1<relative size 3< relative size 2<relative size 4.All of these can be explained in size effect and optimized structure of rocks to clay-rock mixtures.Finally,based on the dry shrinkage cracks of clay-rock mixtures,4 typical destruction models were put forward including “bypass”,“diversion”,“inclusion”,“penetration”.It can also been found that round rocks had a certain concentration effect on the development of dry shrinkage cracks,and the angular rocks had an inductive effect.(Chapter three)(3)Studying the response characteristic of clay-rock slopes with different rock content and distribution characteristic in method of programming and numerical analyzing under the effect of EI-centro earthquake.The specific contents were as follows.Firstly,programing the recognizing and generating orders of clay-rock slopes considering the rock gradation,shapes,contents,positions with MATLAB and VBA.The acceleration response characteristic and slope stability were analyzed in 0%?10%?20%?30%?40%?50%?60% rock content respectively.Then the acceleration response characteristic and slope stability were analyzed according to the distribution of grater rocks including surface of slope,top of slope,middle of slope and foot of slope.Finally,the 3 typical destruction models were put forward including local failure at top of slope,overall landslide in the shallow slope,and overall landslide in the deep slope.(Chapter four)... |
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