(1. Key Laboratory of Geotechnical Mechanics and Engineering of Ministry of Water Resources，Yangtze River Scientific Research Institute，Wuhan，Hubei 430010，China；2. Construction Headquarters of Pu-Xuan Expressway of Yunnan Province，Xuanwei，Yunnan 655400，China；3. China Merchants Chongqing Communications Research and Design Institute Co.，Ltd.，Chongqing 400067，China)
Abstract：In order to reveal the pullout mechanism of tunnel-type anchorages，the deformation characteristics and the potential failure patterns of surrounding rocks and to verify the design safety factor of the tunnel-type anchorage，a field model test with the similarity ratio of 1∶25 for tunnel-type anchorage was conducted in the exploration cave of the Puli Bridge. By performing the elasto-plastic and rheological tests under different loading conditions，the load transmission，deformation distributions and rheological characteristics of the anchorage and surrounding rocks were obtained. The test results show that the distribution curves of maximum deformation at the rear surfaces of anchorage and surrounding rocks exhibit symmetrical double-peak shapes，and those of the frontal surfaces exhibit upward convex shapes. The deformations at the rear surface are bigger than those at the frontal surface. The maximum deformation under 8P load(where，P is the design load) is only 61 μm，and the maximum deformation under 50P load is 566 μm. Due to the clamping effects of the surrounding rocks，the stress in the rear end diffuses very slowly to the front under overloading conditions. Under 50P load，the strain in the front end is only 3% of that in the rear end. The stress concentration clearly occurs at the rear end of the concrete anchorage and the strain is partly irreversible，i.e. the plastic deformation occurs. Having considered that the quality of rock masses at the testing area is better than the one of the prototype tunnel-type anchorage，the overloading stability coefficient is recommend to be larger than 8. As there is no observed rheological behavior under 6P load，the long-term stability coefficient is considered to be larger than 6.
肖本职，吴相超，彭朝全. 重庆鹅公岩大桥隧道锚碇围岩稳定性[J]. 岩石力学与工程学报，2005，24(增2)：5 591-5 597.(XIAO Benzhi，WU Xiangchao，PENG Chaoquan. Stability of the anchorage wall rock of tunnel for Chongqing Egongyan bridge[J]．Chinese Journal of Rock Mechanics and Engineering，2005，24(Supp.2)：5 591-5 597.(in Chinese))
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2015, Vol. 34 
