长大锁脚在软岩大变形隧道施工中的应用

Application of Long Feet-lock in the Construction of Large Deformation Soft Rock Tunnel

软岩大变形隧道开挖后的蠕变效应致使围岩的松动范围不断变大,由此引起的山体应力增大导致支护越来越困难,这就要求施工中需要根据不同的地质情况适当增强初期支护的承载能力,初期支护形成后及时采取各种注浆锚固的措施来控制松动范围。相对于软岩隧道采用复杂的施工工法(如CD、CRD等工法),施工进度缓慢且也无法保证控制大变形,长大锁脚锚管的快速施工和注浆锚固后将控制围岩变形的优势凸显出来。经过牡绥铁路兴源隧道的施工验证,长大锁脚是控制软岩大变形比较有效的措施。

Creep deformation effect of the soft rock tunnel, the after excavation will result in the loosening range of sur- rounding rock increases, due to the increase in the mountain stress supporting becomes more and more difficult, which re- quires the bearing capacity of the initial support to be properly enhanced in the construction according to different geological conditions. After the formation of initial support, various grouting anchorage measures are taken to control the loose range. Compared with the construction methods of complex soft rock tunnel （such as CD, CRD and other methods）, the construc- tion progress is slow and can not guarantee the control of large deformation. The rapid construction of long feet-lock anchor pipe and the advantages of controlling the deformation of surrounding rock after grouting anchorage will be highlighted. Through the construction verification of Xingyuan Tunnel in Musui Railway, it is turned out that the long feet-lock is an ef- fective measure to control the large deformation of soft rock.