非均质黏土地基隧道环向开挖面稳定上限分析  

Upper bound analysis for stability of a circular tunnel in heterogeneous clay

作　　者：黄茂松[1,2] 宋春霞[1,2] 吕玺琳[1,2] 

机构地区：[1]同济大学地下建筑与工程系,上海200092 [2]同济大学岩土及地下工程教育部重点实验室,上海200092

出　　处：《岩土工程学报》2013年第8期1504-1512,共9页Chinese Journal of Geotechnical Engineering

基　　金：国家自然科学基金国家杰出青年科学基金项目(50825803);国家自然科学基金项目(50908171);上海市优秀学科带头人计划资助项目(09XD1403900)

摘　　要：基于多块体极限分析上限法,推导了不排水条件下饱和黏性土地基中隧道环向开挖面稳定支护压力的计算公式。编制相应的计算程序,优化得到了隧道环向开挖稳定的最优上限解答。通过与已有极限分析上限解答的对比,验证了多块体极限分析上限法在隧道开挖稳定性分析的适用性。对照隧道开挖稳定的最优上限解的变化规律及相应破坏面的形状,详细分析了隧道埋深比、土体重度及强度非均质性对开挖面极限支护压力和因隧道开挖产生的滑动面范围和位置的影响。在此基础上,进一步基于隧道失稳的简化破坏模式推导了黏性土地基隧道开挖稳定的极限支护压力的简化上限解。通过与已有离心模型试验的对比验证,指出本文上限解可直接用于工程中初步确定开挖面支护压力,为隧道工程设计提供可靠的理论依据。The stability of a shallow circular tunnel in undrained clay layer is examined in the framework of the limit analysis by means of the limit analysis upper bound method.Rigorous upper bounds of the face collapse pressure and failure envelopes are obtained using the rigid multi-block translational collapse mechanism.The multi-block failure mechanism has significant advantages with respect to the existing limit analysis： it takes into account the effect of cover-to-diameter ratio,gravity parameter and heterogeneous parameter.And the present results of the collapse pressure significantly improve the best available solution given by the solutions of other limit analysis.It is concluded that the collapse pressure increases linearly with the increase of gravity parameter,but decreases linearly with the increase of the heterogeneous parameter.Also the configuration of failure envelopes will vary as the cover-to-diameter ratio,gravity parameter and heterogeneous parameter differ.On the basis of those results,a simplified mechanism is obtained and a simplified solution is derived from the upper bound theory of plasticity.Finally the upper bound multi-block solution for the stability of TBM excavation in clays and its simplified solution are demonstrated by comparing with the centrifuge results.

关 键 词：多块体极限分析上限法 隧道开挖稳定 滑动面 重度参数 非均质参数 简化上限解 

分 类 号：TU470[建筑科学—结构工程]