Study On Three-dimensional Experimental Of Water Pressure Characteristics Of Tunnel Lining In Cross Fissured Rock Tunnel

The construction of fractured rock mass in high water pressure rich water area has been one of the technical problems of underground engineering.It is mainly because the groundwater and surrounding rock and lining structure are interdependent and influence each other to form a contradictory system.The influence of groundwater environment and the stability of surrounding rock is the main influencing factor of tunnel construction,which determines the size of water pressure behind tunnel lining.In this paper,the cross-fractured rock mass tunnel is used as the object of study,and the permeability of cement mortar and geotextile is simulated by the three-dimensional model test.The "+" and the relationship between the water pressure and the size of the water pressure on the fractured surface.The main research results are as follows:(1)Self-developed tunnel seepage model test system can be developed to apply the actual hydraulic pressure to 10 MPa.(2)The distribution of water pressure in the crossed fissure surface under the condition of constant fissure is revealed.The water pressure at the top of the fissure plane is the largest,close to the head pressure at the top of the surrounding rock,and the minimum pressure at the bottom of the fissure is the smallest.The top position of the surface to the tunnel lining position where the water pressure suddenly decreases.(3)The distribution of water pressure behind the lining under the condition of cross-fissure constant hydrostatic pressure is that the water pressure is the "egg" shape distribution;the water pressure at the roof of the lining is the largest,the left or right The water pressure at the foot of the wall is the smallest(this is because the drainage holes are arranged at the left and right foot walls,and the water flowing into the vertical blind pipe is discharged from the lining,indicating that the lining of the blind pipe drainage system can make the water pressure behind the lining smaller and evenly distributed).(4)The bottom of the surrounding rock drainage,lining behind the fissure surfaceof the water pressure are generally small,indicating the bottom of the surrounding rock drainage state,can reduce the water pressure behind the lining.(5)Control the different displacement of the tunnel,it is concluded that the greater the drainage capacity of the tunnel,the smaller the water pressure behind the lining.(6)With a ring to the blind position behind the same position where the water pressure should be slightly less than the inflow to the blind water pressure,with the constant increase in water pressure,the change is more obvious.Cross-fissure at the cross-location of the lining behind the water pressure value relative to the non-intersecting position lining the water pressure value is small.(7)Obtained cross-fracture surface permeability coefficient,lining drainage ratio.