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Abstract The different effects of applying the steel frame and the steel grid frame in high geostress region were investigated during the construction of Daliang tunnel in LXS–7 of Lanzhou—Xinjiang double line Railway. The experimental sections applying the section steel and the steel grid are 20 meters in length each. Numerical simulations were carried out. The settlement of the tunnel crown and the arch foot，the horizontal convergence，the surrounding rock pressure and the stress of initial supporting steel framework were compared through experiments and numerical simulation. The section with the steel frame had the settlement and the horizontal convergence controlled more effectively than the one with the steel grid. But the contact pressure of surrounding rock and steel reached 336 kPa，much higher than the cases of the section with steel grid support. In the section of steel grid，the settlement of tunnel crown reached 350 mm after a week，with the rapid displacement increasing. To control the deformation of the surrounding rock，multiple support including the steel grid and the steel frame were set up. The settlement of tunnel crown reached a stable value of 446 mm and the surrounding rock pressure reached 190 kPa. The deformation of surrounding rocks and the stress of initial supporting steel frameworks were finally effectively controlled，so as to indicate that the multiple support is an effective measure of controlling the large deformation of surrounding rocks.
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Received: 18 December 2013
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2014, Vol. 33 
