层状复合地层条件下管片衬砌结构力学特征模型试验研究

针对武汉长江隧道承受高水压和局部区段穿越软硬程度差异极大的层状复合地层的特点,采用盾构隧道–地层复合体模拟试验系统和旋转式水压装置共同作用,完成了在不同水土压力场作用下对层状复合地层和单一地层两种不同地层条件下的管片衬砌结构力学特征相似模型试验,并根据试验结果分析了层状复合地层对盾构隧道管片衬砌结构的力学特征的影响。研究表明,随着水压力加大,管片衬砌结构的平均轴力明显增大而最大正负弯矩略有增长或基本不变;处于坚硬岩层包围区域的管片体结构局部弯矩明显减小;小范围的硬岩层对管片衬砌结构整环最大内力影响不大。该研究为武汉长江隧道的管片衬砌结构设计提供有价值的参考。

Model tests on mechanical characteristics of segment lining structure under multi-layered strata

Aiming at the features of Wuhan Yangtze River Tunnel,that is,a tunnel under high water pressure and across multi-layered strata with widely different hardness,model tests on segment lining structure with different water and earth pressures under the layered strata and single stratum were performed by jointly applying the simulation facilities of shield tunnel-ground complex and rotary water pressure devices.The effect of mechanical characteristics of segment lining structure for shield tunnels under multi-layered strata was analyzed.It was shown that: with the increase of water pressure,the average axial force of segment lining structure increased evidently,and the maximum bending moment increased slightly or did not changed basically;the bending moment of segment lining in the hard rock stratum obviously decreased;the influence on the maximum internal force of segment lining caused by the hard rock in certain region was slight.These results could provide valuable preference to the design of segment lining structure for Wuhan Yangtze River Tunnel.