On the Large Squeezing Deformation Law and Classification Criteria for the Lanzhou-Chongqing Railway Tunnels in Soft and High Geostress Rocks
(1 China Railway First Survey and Design Institute Group Ltd., Xi'an 710043; 2 School of Civil Engineering, Shijiazhuang TIEDAO University, Shijiazhuang 050043)
Abstract：
It is commonly believed that it is inevitable for a tunnel in soft rock to incur large deformation due to squeezing under high geostress. To control tunnel deformation in squeezing rock, this paper studies the deformation law, classification criteria, and corresponding countermeasures in light of the engineering characteristics of the squeezing-rock tunnels on the Lanzhou-Chongqing railway, the analytic solutions to elastic-plastic displacement of a circular cavity in homogeneous rock, and the rock parameters specified in current Chinese railway tunnel standards. Based on the analytical results and Hoek's unsupported rock-squeezing classification criteria, and considering the effect of support resistance, it introduces classification criteria with three deformation levels, which would be determined by indicators such as the relative deformation and strength-stress ratio in the design stage. A three-level verification standard, deformation management criteria, and countermeasure during the construction stage are put forward by using deformation value and deformation rate as the classification indicators. Tunnel deformation is controlled to a certain degree with the help of the research results.
LI Guo-Liang-1,
LIU Zhi-Chun-2,
ZHU Yong-Quan-2
.On the Large Squeezing Deformation Law and Classification Criteria for the Lanzhou-Chongqing Railway Tunnels in Soft and High Geostress Rocks[J] MODERN TUNNELLING TECHNOLOGY, 2015,V52(1): 62-68
2015, Vol. 52 