倾斜层状泥岩中隧道变异机理及支护措施研究

结合都(江堰)汶(川)高速公路龙溪隧道,根据现场监测位移值,对比模型试验及理论分析结果,对倾斜层状泥质岩层中隧道变异机理及支护措施进行了研究。研究结果表明,倾斜层状泥岩遇水产生微膨胀,在支护结构拱腰形成一个高集度的偏压荷载,且随着时间推移荷载值逐渐增大,支护结构达到屈服后,在开裂断面处形成一个塑性铰,致使支护结构变形较大但仍然保持稳定;同时,在隧道拱腰垂直倾斜岩层面安设加密加长锚管,使偏压荷载有效转移,充分调动围岩本身的自承能力,有利于整个支护结构的安全。

Research into Variation Mechanism and Support Measure of Tunnel in Titled Banded Mudstone

Variation mechanism and supporting measure of tunnel in titled banded mudstone were studied according to the displacement of field monitoring,model experiment and theoretical analysis at LongXi tunnel of the motorway from Dujiangyan to Wenchuan.The(results) show that micro-expansion would occur when titled banded mudstone encountering water,which would result in higher intensity inclined press load on arch lumbus of the supporting structure.When the supporting structure yielded,a plastic hinge would appear at cracked section which causes the supporting structure to deform badly but still in stable condition.At the same time,dense and extended bolts are installed vertically making the gradient rock stratum at the arch lumbus of tunnel to transfer the inclined press load effectively and to(mobilize) self-supporting capacity of rocks.It is beneficial to the safety of the whole supporting structure.