多位移反分析浅埋偏压隧道初期支护荷载分布研究

Study of Load Distribution Rules of Primary Support of Shallow-covered Unsymmetrically Pressured Tunnel by Using Multi-displacement Back Analysis Method

为了直接求解浅埋偏压隧道支护结构承受的围岩压力荷载,确保隧道支护结构施工稳定性,解决监控数据难以直观反馈施工优化的技术难题,采用拱顶沉降与水平收敛相结合的多位移反分析法,建立平面有限元模型,引入应力释放率与荷载偏压参数,结合浅埋偏压隧道特点,运用影响值加载原理,推导了围岩偏压分布公式。结合工程实例,对比同断面压力盒数据表明,利用多位移反分析法推导的偏压围岩分布公式可靠,计算结果可靠,公式系数的调整能有效配合并指导施工变更,以期为相似地质条件下隧道监控量测反馈施工再设计提供参考。

A plan finite element model is established by means of multi-displacement back analysis method,so as to learn the rock stress distribution rules on support structure of shallow-covered unsymmetrically pressured tunnel.Meanwhile,the stress releasing rate,unsymmetrical pressure and influencing value loading principle are adopted in order to obtain formula of rock stress distribution. The comparison between calculated results and measured data shows that the formula and calculated results obtained are feasible and effective. The study results can provide references for similar projects in the future.