深埋长隧锚杆对围岩支护效应的模型试验研究

采用新研制的环氧-硅胶系的相似模型材料，在解决一系列制作、安装、测试技术问题基础上，通过在大型真三轴模型试验机上形成相同的边界条件，从而对毛洞和锚杆加固模型、不同锚杆加固深度模型进行对比，得出锚杆加固后对围岩影响的规律，即锚杆加固区的应力较毛洞相应区内的应力均有所提高，而在锚杆加固区外围岩应力渐趋于此处毛洞的应力值；锚杆加固区中的最大应力一般也成了整个隧道围岩应力的最大值或接近最大值；锚杆的锚固作用还使毛洞中出现的拉应力状态转化为加固区内岩体的压应力状态。随着支护深度的加大，洞壁处的径向及切向压应力也在不断提高，从而利于增大岩体稳定性；同时，锚杆支护模型在不同加载级下应力分布趋势相同，也说明一定埋深范围内、不同埋深的软岩洞室中锚杆支护对围岩的影响是相同的；通过支护前后模型的应变差对比看出，在拱顶和拱腰分别形成了曲线和近似直线的径向应变差分布，对比结果为研究锚杆机制中的锚杆剪应力分布提供了试验基础。

Experimental research on supporting effect of bolts on surrounding rock in deeply buried long tunnel

Adopting new developed epoxy series-colophony series material as the model simulation material, through solving a series of technological matters in execution and installation and testing, comparing bolt-reinforced tunnel model with unreinfoeced tunnel model and with various length bolt models by forming same boundary condition in large-scale real triaxial test machine, some rules about how bolt affects the surrounding rock in final are obtained. The stress rises in reinforced area than that in unreinforced model while the stress out of the reinforced area tendences to same standard in both models; the peak stress in reinforced area becomes or approaches the maximum stress value among the surrounding rock; the tensile stress status in unreinforced model alters to compressive stress in reinforced model by bolt effect. The compressive stress in radial and tangential direction enhances with the length of bolt adding and sequentially the stability of surrounding rock enlarged. In addition, the fact that the distribution trend of stress becomes same in various loading rank indicates that the affection by bolt supporting goes in the same way in different deep tunnel within a certain depth. Finally, the gap value of radial strain approaches curvilinear distribution in top of tunnel while that in hance of tunnel approaches linear approximately; and it provides practical base for researching shear stress distribution along bolt in bolt mechanism.