大跨度岩溶隧道施工工法比选

随着我国高速公路的发展，在岩溶地区修建隧道工程日益增多，选择合理施工工法是隧道施工安全稳定的重要一环。根据大跨度岩溶隧道中溶腔的发育程度、发育位置以及溶腔内充填物性质的不同，隧道需采用不同施工工法。以乐昌至广州高速公路段某大跨度岩溶隧道为例，采用有限元软件对其进行了三台阶法、单侧壁导坑法和双侧壁导坑法等3种施工工法的比选。最后得出结论：双侧壁导坑法在岩溶隧道施工中能有效的控制围岩塑性区的发展和洞周位移，并且能够有效改善围岩的受力状态，适当提高衬砌的应力水平，是较为合理的施工工法。可为岩溶地区高速公路隧道设计施工提供一定的参考。

Comparison of the Construction Methods of Longspan Karst Tunnel

There are more and more Karst tunnels to be constructed in our country,the construc-tion methods of Karst tunnel are also increasingly diverse.Choosing reasonable construction method is one of the most important aspects of security.Different construction methods should be used depending on location ,degree and the property of the fillers of the longspan karst cavity.In background of a certain Karst tunnel in the expressway from Lechang to Guangzhou,the author simulated three construction meth-ods：the three steps method,single-side-drift method and double-side-drift method using the finite ele-ment software Abaqus,and analysed the formation and development of the plastic zone and the displace-ment of the surrounding rock,and come to the conclusion：double-side-drift method can not only control the development of the plastic zone and the displacement of the surrounding rocks,but also can can effec-tively improve the stress of surrounding rock,appropriately raise the level of stress of the lining.It is the proper construction method for Cavity Karst Tunnel.The conclusion provide reference for tunnel construc-tion under similar conditions.