| With the rapid development of basic construction and the further advance of the western development strategy,the highway engineering,railway engineering and underground engineering of our country's have been quickly developed.A lot of long-large deeply buried tunnel projects going through the high stress areas and soft rock body have been started, large deformation of soft rock and other related geological disasters will constantly turn up. Therefore, as an important content of the New Austrian Tunneling Method-to'establish controlling baseline will have great economic significance and practical value to the construction of the tunnel project.This paper choosed the practical engineering of Ping Tianchi Lan-Yu Railway Tunnel as background,used finite element software MADIS/GTS to simulat the two-dimensional number,and then analyzed the ultimate displacement of tunnel surrounding rock,established tunnel displacement deformation control benchmarks which in different depths and different construction phases.This paper described the research situation of soft rock tunnel control benchmarks, compared and described various theories and research methods;briefly introduced the general situation of Ping Tianchi Lan-Yu Railway Tunnel,and then discussed the reasons of large deformation of soft rock tunnel.This paper emphasized on simulating numbers of the limit displacement of soft rock tunnel using Ping Tianchi Lan-Yu Railway Tunnel as background,analyzed the limit displacement of tunnel,and then sum marised the numbers of soft rock tunnel's displacement deformation control benchmarks which in different depths and different construction phases.By analyzing the summarizing,this paper obtained some law and conclusions about soft rock tunnel controlling benchmarks:(1) Combining with the general situation of Ping Tianchi Lan-Yu Railway Tunnel, this paper introduced time and space effect about the excavation process of weak rock tunnel,and then found the causes of large deformation of soft rock tunnel.(2) This paper took rock stability principle of plastic strain and mutation as the basic theory,conbining simulation results which was abtained by finite element analysis software MADIS/GTS in different indoors of tunnel excavation,got the limit displacement at different depths of the tunnel (100 m,200 m,300 m), different excavation conditions (upper, middle and lower bench excavation conditions)(3) According to the construction of site and the limit displacement which gotten by numerical simulation of indoor this paper proposed the concept of deformation control three-level management which was aimed at different depth and then obtained the control ben chmarks for large deformation of weak rock tunnel under different depths (100 m,200 m, 300 m).(4) Briefly analysized theory about large deformation of soft rock tunnel support and these measures played aguiding role for the latter part of design and construction of tunnel support. |
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