Research Of The Affect That Chongqing Nanshan District Groundwater Systems Caused To The Safety Distance Of Tunnel Built In Different Period

With the exploitation of underground space, the problem of mutual influencebetween tunnel and other buildings arise inevitably. Especially in busy urban areas, thedistance between tunn-el and tunnel, tunnel and other buildings are getting smaller andsmaller,So it is necessary to study the problem of close overlapping tunnel influenceeach other. Tunnel is a kind of linear stru-ctures. In the process of tunnel constructionoften will encounter all sorts of different properties of underground rock or soilmass.Especially,the section which the deep buried tunnel is more complex geologycondition. Encountering groundwater in tunnel construction process will inevitably. Theexcavation of the tunnel, changed the original groundwater seepage situation and tunnelbecame the groundwater drainage channel. So the water gushing in tunnel becomecommon geological disasters in tunnel construction process. In addition,along with ourcountry water resources consumption gradually, undrained tunnel is increasing. In viewof this kind of situation, Study on safe distance between tunnels when groundwaterexite is very meaningful.NanShan tunnel group as the background, according to the law of groundwaterseepage, according to the fluid-structure interaction theory, this paper simulate tunnelsin NanShan district which are built in different periods, study the issue of reasonableconsidering groundwater tunnel spacing.this paper hope to be useful for similar projectson future tunnel construction and design. This paper mainly do the following work：①Research on groundwater seepage theory and consolidation theory;②Research on external water pressure theory as well as simulation realizationmethod in FLAC③Using FLAC to simulatie early excavation of tunnel, rise of water level, andimpact on the tunnel lining;④The influence on the pore water pressure distribution, and the old tunnel lininginternal force as new tunnel excavation;⑤The change of internal force on lining and ground surface settlement due totunnel change;⑥Analysis of simulation results and conclution about the range of reasonable spacing.