水平地震作用下浅埋隧道围岩压力的计算方法研究

Ground loading of shallow tunnels under seismic scenario

以现行规范中浅埋隧道围岩压力计算的力学模型为基础,引入水平条分原理和水平地震系数,建立一套地震工况下浅埋隧道围岩压力计算方法。与规范方法及杨小礼方法相比,将静力工况与地震工况结合到统一力学模型中,且将岩土体的两个强度参数作为独立因素考虑,且能考虑岩土体分层的实际情形。通过简单算例的对比分析,认为将黏聚力和内摩擦角作为独立因素考虑,能更为准确地计算隧道围岩压力;通过多层算例的对比分析,认为隧道自身所穿越地层的围岩条件,对其围岩压力分布特性起主要作用;进一步利用方法,探讨岩土体强度参数和水平地震系数,对破裂角和竖向围岩压力的影响。研究成果可为浅埋隧道的抗震计算或设计提供更为准确可靠的理论依据或技术参考。

Based on the calculation diagram specified by the current codes,the horizontal slice principle and the horizontal seismic coefficient are introduced to establish a general method for calculating the ground loading of shallow tunnels under seismic scenario.Compared with the traditional methods,it can unify the static and seismic scenarios into one single calculation diagram,separate two strength parameters apart as independent factors,and consider the multiple-layered ground condition.The case study of simple ground shows that the separation of cohesion and friction angle can describe the ground loading in a more accurate way.The case study of multi-layered ground shows that the ground condition within the range of tunnel itself plays a key role for the distribution of ground loading.Moreover,the influences of two strength parameters and horizontal seismic coefficient on the rupture angle and vertical ground loading are further analyzed through a series of case studies.The proposed method provides a reliable theoretical basis and technical reference for the anti-seismic analysis of shallow tunnels.