中文摘要：

运用Acutronic661型离心机研究超前小导管注浆加固圆形隧道的塑性变形机制，试验隧道在平面应变条件下的超固结黏土中开挖，小导管采用具有一定硬度的合成树脂模拟，管间相互重叠形成拱形加固区，设置在圆形隧道开挖面的两侧．试验目的在于研究隧道建设过程中小导管注浆“洞侧加固”工艺对地表沉降和隧道稳定性的影响．在此基础上，从塑性极限分析上限法的基本原理出发，构建小导管注浆黏土隧道的垮落机制，采用解析法导出双角变量稳定率上限方程，通过该方程进一步讨论隧道埋深、土体强度、小导管注浆体对单圆形隧道稳定率上限解的影响．最后由离心模型试验结果证实其上限解的正确性．

英文摘要：

The influence that the forepoles have on the patterns of a single tunnel plastic collapse was discussed by using Acutronic 661 and a series of plane strain centrifuge model tests in over-consolidated clay were conduct- ed. Tests were carried out on a circular cavity with zygomorphous stiff resin inclusions embedded around the periphery of the tunnel. These inclusions simulated elements of a secant pipe or forepole arch system. The aim of the experimental work was to study the ground response due to simulated tunnel construction and to see how the zygomorphous stiff inclusions affected the tunnel stability. According to the principle of the upper bound theorem of plastic limit analysis, a collapse mechanism of the single circular tunnels with embedded forepoles in cohesive soil was established. An upper bound equation of stability ratio was obtained based on two angle variables. The upper bound solutions of stability ratio under different soil covers above the tunnel, undrained shear strength at tunnel axis level and embedded forepoles range were discussed through the equation. In the end, the correctness of the upper bound solutions was proved by the results of centrifugal model tests.