富水岩溶隧道掌子面安全岩柱厚度研究

富水岩溶隧道施工时掌子面前方的安全岩柱对保障隧道的安全施工至关重要。为了计算出较为合理的隧道掌子面安全岩柱厚度,以华丽高速营盘山隧道为依托,基于塑性区贯通准则及位移突变准则,建立三维流固耦合数值模型,分别对不同埋深、溶洞内水压力及开挖方法下的掌子面安全岩柱厚度进行了研究,并给出掌子面安全岩柱厚度的区间。结果表明：隧道安全岩柱厚度随隧道埋深及掌子面前方溶洞内水压增加而增大；隧道一次开挖洞径越小,支护越及时,安全岩柱厚度越小；最小安全岩柱厚度区间随隧道埋深增加而增大,但随掌子面前方溶洞内水压增大而减小。采用CRD法开挖时,掌子面安全岩柱厚度及安全岩柱厚度区间均最小,对岩溶隧道掌子面的稳定性也最好。

Study of safe rock column thickness at the working face of water-rich karst tunnels

The safety rock column in front of the working face during the construction of water-rich karst tunnel is crucial to ensure the safe construction of the tunnel. In order to calculate a reasonable safety column thickness at the working face of the tunnel, a three-dimensional fluid-solid coupling numerical model was established based on the plastic zone penetration criterion and displacement mutation criterion in the Yingpangshan Tunnel of the Huali Expressway, and the safety column thickness at the working face was studied under different tunnel depths, water pressure in the cavern and excavation methods, and the interval of the safety column thickness at the working face was given. The results show that: the safety column thickness increases with the increase of tunnel depth and water pressure in the cavern in front of the working face; the smaller the diameter of tunnel excavation and the more timely the support, the smaller the safety column thickness; the minimum safety column thickness interval increases with the increase of tunnel burial depth, but decreases with the increase of water pressure in the cavern in front of the working face. When CRD method is used, the safety column thickness and the safety column thickness interval at the working face are the smallest, and the stability of the working face of karst tunnel is the best.