深埋硬岩特长隧道快速掘进技术研究

对于深埋硬岩隧道,快速掘进技术的运用能够有效缩短工期,从而带来极高的经济效益。选择合理的爆破进尺以减少对围岩的损害是保证快速掘进的前提,同时配合高效的施工方式才能实现快速掘进。采用数值模拟方式,以虹梯关隧道为例,通过松动圈厚度及变形量大小对3,3.5,4,5 m各爆破进尺下围岩的稳定性进行评价,得出快速掘进的理论爆破进尺并应用于工程实际。在理论研究的基础上结合现场施工组织提出深埋硬岩隧道的快速掘进的合理进尺,即Ⅱ级围岩可采用3.5~4 m爆破进尺。

Study on Rapid Excavation Technology for Deep Super-long Tunnels in Hard Rock

The application of rapid excavation technology in the construction of deep super long hard rock tunnels can achieve shorter construction period and thus can result in good economic efficiency. Selecting proper blasting cyclic length, which can minimize the damage to the surrounding rock, is a prerequisite for rapid excavation. In the paper, the broken zone thickness and the deformation of the surrounding rock of Hongtiguan tunnel under 3, 35, 4, 5 m blasting cyclic lengths is evaluated by means of numerical simulation. Theoretical blasting cyclic length is obtained and applied in the tunneling. Finally, rational blasting cyclic length, i.e., 35~4 m in Grade Ⅱ surrounding rock, is proposed on basis of theoretical study and engineering practice.