渗流-应力耦合作用下深埋黏土岩隧道盾构施工特性及其动态行为研究

STUDY OF CONSTRUCTION CHARACTERISTICS AND DYNAMIC BEHAVIOR OF DEEP CLAY STONE DURING SHIELD TUNNELING UNDER SEEPAGE-STRESS COUPLING EFFECT

基于连续介质大变形理论和损伤力学理论,将塑性损伤演化与渗流相互耦合的方法引入到Mohr-Coulomb准则,建立黏土岩弹塑性大变形渗流–应力耦合模型,以ABAQUS软件为平台对其进行二次开发。以比利时黏土岩核废料库工程为背景,在全面分析盾构施工影响围岩稳定性因素的基础上,建立反映施工质量的等代层模型,对不同施工质量时盾构掘进过程中围岩及开挖面的变形、孔隙压力及塑性区的演化规律进行数值模拟。计算结果表明,围岩变形在开挖面附近达到最大值,施工质量对围岩稳定性有明显的影响,施工质量越差,开挖扰动区的范围就越大,并且孔隙压力降低的幅度就越大。研究结果可为软岩隧道设计及施工提供参考。

Based on the theory of large deformation and damage mechanics, an elastoplastic coupling analysis model considering effect of large deformation is set up by introducing damage evolution and seepage-stress coupling into the Mohr-Coulomb criterion. An equivalent layer model is adopted after comprehensive analysis of surrounding rocks associated with shield tunneling. Considering the actual case of construction of connecting gallery of a radioactive waste disposal in the deep Boom clay formation in Belgium, different tunnel construction qualities are calculated by small deformation, large deformation, respectively, by the secondary development of ABAQUS. The distributions of pore pressure, plastic strain and deformation around the tunnel associated with shield tunneling are analyzed in details. The results show that the deformation of surrounding rocks reaches the maximum in the vicinity of the excavation face and tunnel construction quality affects the stability of surrounding rocks significantly. This study is useful for shield tunnel construction and field measurement.