Detection And Safety Assessment Of Water Conveyance Tunnel

Based on the Dalian water supply project,three of the water conveyance tunnels are selected as the research object.A initial inspection is performed to determine the strength of the lining and surrounding rock,and analyze the causes of the tunnel damage.Using the finite element software to simulate the working condition of the tunnels under the influence of the seepage,the safety of the water conveyance tunnels is evaluated.The main contents and conclusions of this paper are as follows:The data of nine water conveyance tunnels related to geological and hydrological conditions,section size,lining structure type is collected and analyzed.Among them,three water conveyance tunnels are inspected.Then,the strengths of lining concrete and surrounding rock are measured.(1)Based on the inspection results,the major damages of the three tunnels are concrete erosion holes,honeycomb pits,concrete efflorescence,leakage from tunnel side wall and vault sheet.(2)According to the similar repair case of water conveyance tunnel damage,the possible causes of the damage of the water conveyance tunnel are analyzed,and the influence of various damage on the safe operation of the tunnel project is evaluated.(3)The seepage-stress coupling analysis model of the tunnel is established.The stress field coupled with the seepage field of the tunnel is simulated and calculated by selecting the different property parameters of surrounding rock and lining.The effects of surrounding rock and lining permeability coefficient,elastic modulus and groundwater level on the seepage field and stress field are studied.(4)Defining typical cases during the construction and operation of the tunnels,the seepage field and stress field are computed.The distributions of pore water pressure,displacement and stress of the rock and lining are obtained.The results show that the tunnel lining is within the range of safety.