Experimental Study On Similar Materials Of Tunnel Weak Surrounding Rock Based On Orthogonal Design

In recent years,with the implementation of the thirteenth five-year plan and the process of urbanization,the number of tunnel projects is increasing day by day.However,the tunnel project still faces many technical difficulties when passing through soft and weak surrounding rock in large-scale tunnel projects in our country.Due to the low strength and large deformation of weak surrounding rock itself,the supporting structure of the project is easy to be destroyed or even collapsed.Therefore,in order to solve the design and construction problems of tunnel soft rock,it is necessary to study the engineering characteristics of tunnel soft rock.Based on orthogonal design,this paper provides theoretical basis and technical support for tunnel soft surrounding rock model test and similar material research through experimental research on similar materials of tunnel soft surrounding rock.Based on the outstanding youth scientific research project of Hunan Province Department of Education--the experimental study on grouting of weak and broken surrounding rock in tunnel,this paper carres out in-depth experimental research on similar materials of tunnel soft surrounding rock,obtains three mechanical parameters of orthogonal test of similar materials by using fully automatic triaxial apparatus,analyzes and studies the similar materials of tunnel soft surrounding rock by ORIGIN and MATLAB and other software.The main research results are as follows:(1)Study the characteristics of the tunnel surrounding rock through triaxial shear test and repeated test.Taking the mechanical parameters of the soft surrounding rock of grade IV tunnel as the reference index,using quartz sand,kaolin,gypsum,water and laundry liquid as materials,based on the principle of orthogonal design,we obtain similar materials which meet the mechanical parameters of grade IV tunnel soft surrounding rock.(2)By sorting out the original test data of mechanical parameters such as internal friction angle ?,cohesion c and gravity y,and adjusting the proportion of similar materials,we get the best proportion of similar materials which meet the IV grade tunnel soft surrounding rock.(3)By using ORIGIN software and the range analysis method to analyze the sensitivity of the factors affecting the test,we obtain the influence degree and trend of the components of similar materials on the physical and mechanical properties of the materials themselves.(4)By using MATLAB software to carry out regression analysis on the test data,we get the empirical equation and its change rule between the factors and the reference index of similar materials.