Research On Influence Of Water Retaining Effect Of Underground Structure On Long Term Settlement Of Tunnel

The long-term ground settlement caused by partial leakage of subway tunnels will have adverse effects on surrounding buildings and underground pipelines.Therefore,it is necessary to study and analyze various factors that affect long-term land subsidence caused by tunnel leakage.In this paper,the long-term land subsidence of the tunnel seepage is simulated by the finite element method.The influence laws of the relevant influencing factors are analyzed.The lattice boltzmann method is used to simulate the seepage barrier effect of the underground structure.Finally,the long-term settlement of the tunnel under the water-blocking effect of the structure is simulated by the finite element method,and the following conclusions are obtained:(1)With the increase of elastic modulus of soil,the long-term ground settlement caused by tunnel leakage is reduced.The higher the initial groundwater level,the greater the long-term ground settlement;with the increase of the relative permeability coefficient of the tunnel lining and the surrounding soil,the long-term ground settlement increases.(2)At the interface between the upstream face of underground structure and the soil,the flow velocity in the front of the structure decreases,the flow velocity in the bottom of the structure increases,the pore water pressure in the front and bottom of the structure increases.At the interface between the downstream face of underground structure and the soil,the flow velocity in the front of the structure decreases,the flow velocity in the bottom of the structure increases,the pore water pressure in the back and bottom of the structure increases.At the interface between the bottom of underground structure and the soil,the flow velocity in the bottom of the structure increases,the pore water pressure in the bottom of the structure increases.(3)When underground structures exist on one side of the tunnel,the ground subsidence gradually decreases with the increase of the depth of the structure,and the stability time of the ground settlement near the structure is more than the stability time of the ground settlement far away from the structure.With the increase of the horizontal distance of the center of the tunnel,the ground settlement gradually increases,and the stability time for the ground settlement in the tunnel side of the underground structure is relatively longer.(4)When underground structures exist on both sides of the tunnel,the subsidence of the ground gradually decreases with the increase of the depth of the structure,and the stability time of the ground subsidence becomes shorter,and when both sides have structures and single side have structures,the settlement difference of the maximum settlement increases.With the increase of the horizontal distance between the structure and the tunnel,the ground settlement increases gradually.The stability time of the ground subsidence on the tunnel side of the structures is relatively longer,and the stability time of the ground settlement without the tunnel side is relatively shorter.