早强锚杆在高地应力层状软岩隧道中的应用研究

以在建的成都-兰州铁路杨家坪隧道为工程依托，选取条件基本相同的30m典型围岩区段为试验段，对普通锚杆、早强锚杆支护时的洞周位移、围岩与初支接触压力、型钢拱架应力及其锚杆轴力进行实测对比分析，探讨了早强锚杆在高地应力陡倾层状软岩隧道中的作用机制。结果表明：高应力软岩隧道中锚杆轴力为拉力，早强锚杆比普通锚杆轴力更大，可以使隧道洞周位移减小40%|早强锚杆使隧道边墙围岩压力和钢架拱顶应力减小，围岩压力分布和钢架受力趋于均匀|早强锚杆通过注浆材料深入围岩，可以提高围岩层面强度|及时发挥锚固作用，抑制了围岩渐进破坏过程，从而减小围岩塑性区|加长了锚杆的拉拔长度，减小围岩与初支接触压力，改善隧道支护的受力状况，有效地控制隧道变形。

Application of early strength bolt in high geostress layered soft rock tunnel

Based on the construction of the Yangjiaping tunnel in Chengdu-Lanzhou railway, 30 meters long tunnel with typical surrounding rock was chosen as the experimental section. The follow items were compared when there exists ordinary bolt or early strength bolt, including displacement of tunnel inner perimeter, pressure between surrounding rock and primary lining, internal force of the steel arch truss and axial force of the bolts. The mechanism of the early strength bolt in the high geo-stress layered soft rock tunnel is discussed. The results show that the axial force of the anchor bolt which in high stress soft rock tunnel is the pulling force, and the axial force of early-strength bolt is larger than that of the ordinary bolt, which can reduce the displacement of tunnel by 40%. The early-strength bolt makes the pressure of the surrounding rock of the tunnel side wall and the strain of the steel arch truss in the vault area reduced, so that the distribution of surrounding rock pressure and the strain distribution of steel arch truss tend to be uniform. The early-strength bolts improve the strength of the surrounding rock layer by grouting material deep into the rock, and inhibit the gradual failure process of surrounding rock by playing anchoring effect in time, thus the plastic zone of the surrounding rock is reduced. The pressure between surrounding rock and primary lining is reduced by lengthening the pick-up length of the bolt, then the stress condition of the tunnel support is improved, the tunnel deformation is effectively controlled.