Research On Seepage Field And Lining Internal Force Of Urban Tunnels In Water-Enriched Region

Tunnel construction will face to the problem of underground water in urban region. The water table usually stays in a high lever, especially in southern city. In the meantime, underground water is also a precious property for city issues which is so important and irreplaceable that can’t be drained casually.There are two main parts of urban city construction worth attention:on the one hand, we should focus on the seepage field evolution of ground water, identify the flow direction of groud water through the changes of seepage field, and keep an eye on the key area; on the other hand, lining structure type and external loads should be selected correctly in water-enriched region. In consideration of the unmendable damage caused by serious accident, it is necessary to assure lining structure safty. The researchs are based on the eastern highway connection tunnel project in the downstream of Shenzhen reservoir, and numerical simulation was adopted to develop relative researchs. The main contents and results are listed as follows:(1) There had established a large-scale three-dimensional seepage field model of Shenzhen reservoir downstream urban tunnels with present engineering geology and hydrogeololgy data, and the model was used to check initial water table with borehole data. The seepage field evolution after tunnel construction was analyzed, and chages of the evolution were got.(2) There had established a three-dimensional FDM model with present engineering geology and hydrogeololgy data, and fluid-solid coupling analysis were taken to solve this problem. A primary research on the reduction factor of water pressure was carried on by analyzing the water pressure evolution of key point. A reasonable range of the reduction factor which suited this project was got.(3) The seepage field evolution and the reasonable range of water pressure reduction factor were got. According to the tunnel sections and section distribution, some typical tunnel sections were chosed to analyze structural internal force and to judge the tunnel lining safty. A method was introduced in this thesis by using multiple numerical simulation softwares to acquire more accurate state of structure mechanical property.