Stratum Deformation Discipline Monitoring And Engineering Application Research In Loess Subway Tunnel Construction

This article rely on the monitoring measurement of running tunnel between Nanmen-Nanshaomen and Caochangpo-Xiaozhai in Second Subway Line of Xi'an, research the program design, data processing, as well as in practical engineering applications of vertical displacement measurement of the shallow tunnel section roof surrounding rock by real-time and full-time displacement changes, and made the following main results:1. To establish a set of practical and effective displacement measurement technical methods of tunnel roof rock mass, solved the lag and incomplete of measurement information effectively, so that rock mass information be a complete reflection in the first time.2.The paper discusses the generation mechanism of loess subway tunnel roof rock mass displacement, proposes the displacement generation of subway tunnel surrounding rock have not only relevant with geological factors, but also with the design parameters and construction methods and other factors of tunnel, and find that tunnel construction footage is the main factor.3.The paper also has-studied the deformation features of tunnel roof rock mass in the stability situation:the largest deformation point in the vicinity of vault and it is the center point of expansion. The trend of expanding of both sides is greater than the surface. Due to the continuity of strata, deformation features is similar with tunnel vertical or horizontal; but because of the discreteness of rock material, the vertical settlement from tunnel roof to ground surface after excavation is large when close to tunnel roof and small when far from tunnel roof.4.Summed up the vertical displacement of tunnel roof surrounding rock showed settlement trough form by the tunnel horizontal, and closing to the formula Peck.Engineering practice has proved that the application of this article research results for the Second Subway Line of Xi'an construction and has provided that the basis for follow-up at the same time a similar project design and construction experiences. So results of this article have the great value to promotion.