双隧道开挖进尺对其掌子面稳定现场监测和数值分析——以安石隧道为例

以云县至凤庆高速公路隧道工程为背景,提出采用现场监测和数值分析结合的可行性研究方案.通过数值分析与实际工程对掌子面的位移进行研究.详细分析不同开挖进尺情况下掌子面前方不同位置处的岩层位移变化规律后,发现掌子面开挖进尺与掌子面前方岩层变形规律,开挖进尺越大,对其掌子面的稳定越不利,同时发现掌子面岩层可以提供一部分阻力,阻止掌子面前方岩体朝掌子面移动,以及掌子面上方岩层的重力势能作用.提出红线开挖进尺的确定方法和现场实际开挖进尺的确定准则;讨论了施工过程中掌子面前方岩层存在的挤出现象,表明采用红线开挖进尺乘以安全系数更能保证现场的施工安全.

Field Monitoring and Numerical Analysis of Tunnel Face Stability by Double Tunnel Excavation Footage: Taking Anshi Tunnel as an example

Based on the tunnel project of Yunxian-Fengqing Expressway, a feasibility study scheme combining field monitoring and numerical analysis is proposed. The displacement of the palm surface is studied by numerical analysis and practical engineering. After a detailed analysis of the rock displacement variation at different positions in front of the face under different excavation footage, it is found that the excavation footage of the face and the deformation law of the rock in front of the face. The greater the excavation footage is the more unfavorable to the stability of the face. At the same time, it is found that the rock in the face can provide some resistance to prevent the rock in front of the face from moving towards the face and the gravitational potential energy of the rock above the face. The determination method of red line excavation footage and the determination criterion of actual excavation footage on site are proposed. The extrusion phenomenon of the rock stratum in front of the working face in the construction process is discussed, indicating that the red line excavation footage multiplied by the safety factor can better ensure the safe construction of the site.