基于等减载率的高填明洞长期性能

Long-term Performance of High-filled Open Cut Tunnel Based on Equal Load Reduction Rate

为探究减载材料差异对衬砌变形及安全性的长期影响,选取可发性聚苯乙烯板(EPS)板、低压实土和橡胶颗粒混合土3种减载材料,填土采用高压实土,利用试验与数值模拟相结合的方式,分析当减载率相同时,不同减载材料与高压实土共同蠕变对高填明洞长期性能的影响。结果表明:4种材料的蠕变曲线分为衰减蠕变和稳态蠕变两个阶段,同一荷载作用下,材料蠕变应变大小依次为:EPS板>橡胶颗粒混合土>低压实土>高压实土;不同减载措施下填方中心蠕变位移最大,向外环形扩散降低,且填方蠕变位移大小依次为:EPS板>低压实土>橡胶颗粒混合土,橡胶颗粒混合土可以有效抑制填方的蠕变位移。当减载材料与高压实土共同蠕变时,拱顶、拱肩先下沉再回弹,拱腰和边墙先向外扩散再向内收敛,拱顶沉降和拱腰收敛变化值最大;拱顶安全系数增量较大,但蠕变稳定后拱脚安全系数最小。不同减载措施下衬砌变形与安全系数变化大小依次为:低压实土>橡胶颗粒混合土>EPS板。

In order to explore the long-term influence of the difference of load-reducing materials on the deformation and safety of lining,three kinds of load-reducing materials,expandable polystyrene board(EPS)low-pressure solid soil and rubber particle mixed soil,were selected.The high-pressure solid soil was used as the filling soil.The influence of creep of different load-reducing materials and high-pressure solid soil on the long-term performance of high-filled open-cut tunnel was analyzed by means of experiment and numerical simulation.The results show that the creep curves of the four materials can be divided into two stages:decay creep and steady-state creep.In addition,under the same load,inward,and the vault settlement and the haunch convergence change value are the largest.The safety factor increment of the vault is large,but the safety factor of the arch foot is the smallest after creep stability.The change of lining deformation and safety factor under different load reduction measures is as follows:low pressure solid soil>rubber particle mixed soil>EPS plate.