STABILITY ANALYSIS OF TUNNEL WORKING FACE IN COMPOSITED SANDY SOIL
LIU Wei1，2，TANG Xiaowu1，GAN Penglu1，SAVIDIS S2
(1. College of Civil Engineering and Architechture，Zhejiang University，Hangzhou，Zhejiang 310058，China；
2. Department of Civil Engineering，Technische Universität Berlin，Berlin 13355，Germany)
Abstract：The tunnel working face easily collapses when tunneling is conducted in the composited sandy soil, thus it is important to maintain the proper support pressure for the working face stability. According to the frictional characteristics of sandy soil，the upper bound analysis is applied to analyze the working face stability by using the improved 3D kenimatically admissible mechanisms, and the formula of the minimum support pressure for the working face stability is obtained. As the crossed soil is defined，the influence of the tunnel diameter，the depth ratio，the ground surface surcharge，the cohesion and the friction angle of the cover layers and the relative thickness ratio of cover layers on the support pressure is studied. This study presents an accurate estimation of support pressure for the tunnel working face stability in the composited sandy soils as well as an important theoretical reference to the similar practice projects.
竺维彬，鞠世建. 地铁盾构施工风险源及典型事故分析的研究[M]. 广州：暨南大学出版社，2009：78-86.(ZHU Weibin，JU Shijian. Research on risk sources and typical accidents in tunneling construction[M]. Guangzhou：Jinan University Press，2009：78-86. (in Chinese))
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2013, Vol. 32 
