Experimental study on dynamic mechanical characteristics of tunnel structure passing through fault zone
In order to reveal the structural mechanical response characteristics of the tunnel during passing through fault zone,indoor model tests were conducted to study the changes in surrounding rock pressure,surrounding rock displacement,and lining stress during excavation construction using the step method with fault dip angles of 45°,60°,and 75°.The results show that the larger the dip angle of the fault,the higher the surrounding rock pressure value.When the dip angle of the fault is 75°and 60°,the surrounding rock pressure is 1.169 times and 1.089 times that of 45°,respectively.The influence range of surrounding rock pressure at the arch is 1.0 time of the tunnel diameter,and the influence range at the arch waist and side walls is 0.5 times of the tunnel diameter.The larger the dip angle of the fault,the higher the radial displacement value of the surrounding rock.When the fault dip angle is 75°and 60°,the radial displacement reaches 1.112 times and 1.057 times that of 45°.The displacement of the surrounding rock at the arch has an impact range of 1.0 time of the tunnel diameter,and the impact range at the arch waist and side walls is 0.5 times of the tunnel diameter.Due to the presence of fault structures,a large amount of loose pressure is formed after tunnel excavation,and the lining structure is in a"flat and flat"stress state.The lining stress is highest at the side wall position,followed by the arch crown and arch waist.The larger the dip angle of the fault,the higher the stress value of the lining.The stress of the lining at the arch crown position in the first construction cycle is 1.176 times and 1.079 times that of 45°when the fault dip angle is 75° and 60°,1.187 times and 1.089 times at the arch waist,and 1.169 times and 1.082 times at the side wall.The stress of the lining at the arch crown position in the second cycle is 1.136 times and 1.067 times that of 45°when the fault dip angle is 75°and 60°,1.158 times and 1.075 times at the arch waist,and 1.156 times and 1.077 times at the side wall.
万方数据
维普
