黏土隧道小导管注浆离心机模型试验

Centrifuge Model Test of Clay Tunnel with Embedded Small Duct Grouting

为探讨小导管注浆范围对隧道稳定性及地面沉降的影响,进行了超前导管注浆加固机理与性能优化的系列离心机模型试验.试验隧道在平面应变条件下的超固结黏土中开挖,小导管注浆加固区设置在圆形隧道开挖面外围,采用具有一定刚度的环状合成树脂模拟.试验结果表明:随着小导管环向布置范围的扩大,隧道塑性区及滑移面由拱顶向拱脚转移,深部土体逐渐开始参与承载,隧道稳定性提高;"洞侧加固"方案对提高加固效果最为经济;覆跨比等于2时,该方案可使黏土隧道施工期间的最大地面沉降减小约10%.

Plane strain centrifuge model tests were carried out to investigate the influence of small duct grouting range on tunnel stability and ground subsidence. The consolidation principle and performance optimization of advanced duct grouting were discussed. The tests were carried out in a circular cavity with stiff resin inclusions embedded around the periphery of the tunnel in over-consolidated clay in plane strain. The experimental results show that with the extension of ducts＇ circumferential setting range, tunnel stability is improved, tunnel plastic zone and slip plane transfer from tunnel crown to its invert, and deep soll becomes involved in bearing load. The shoulder reinforcement scheme is one of economic ways to improve the consolidation effect in accordance with the findings. When the cover- span ratio equals to 2, this scheme can be reduce the maximum ground subsidence in clay tunnel construction by 10%.