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针对岩体的应变软化特性,基于双线性损伤模型和应力等效原理,推导了卸荷围岩应力状态的损伤理论解析解,进而分析了隧道开挖后围岩应力随径向距离的分布特点,从而将卸荷后的围岩分为四个区域,即完全损伤区、非完全损伤区、弹性区和原岩应力区。根据围岩的实际破坏特点,采用两种不同的方法对完全损伤区的应力解进行了修正。通过对隧道围岩应力分布特点的分析,提出了基于损伤理论的隧道围岩松动圈的界定标准,认为完全损伤区即为隧道围岩松动破坏区。最后运用损伤理论解析解对张石高速公路隧道围岩松动圈进行了估算预测,同时将预测结果与现场监测值进行对比分析,验证了理论解的适用性。
Based on the bilinear damage model and stress equivalence principle, the analytical solution to the damage state of stress state of unloading surrounding rock is deduced for the strain softening characteristics of rock mass, and then the distribution of surrounding rock stress with radial distance after tunnel excavation is analyzed So that the unloading of the surrounding rock is divided into four areas, namely the complete damage zone, incomplete damage zone, elastic zone and the original rock stress zone. According to the actual damage characteristics of the surrounding rock, two different methods were used to correct the stress solution in the completely damaged zone. Based on the analysis of the stress distribution characteristics of the surrounding rock of the tunnel, the definition criteria of the surrounding rock loose ring based on the damage theory are proposed. It is considered that the complete damage zone is the loose rock failure zone of the tunnel. Finally, the damage theory analytical solution is used to estimate and predict the loose ring of the surrounding rock of Zhangshi Expressway tunnel. At the same time, the predictive results are compared with the on-site monitoring data to verify the applicability of the theoretical solution.