全断面硬岩隧道掘进机隧洞钢拱架支护现场试验的力学性能及稳定性判断

以北疆供水二期KS隧洞工程为依托,通过实时监测钢拱架内外翼缘应力并分析其分布特征和变化规律,利用材料力学原理计算钢拱架轴力和弯矩,结合钢拱架稳定性判断流程分析其安全等级,研究结果表明,钢拱架整体表现为受压状态,同一测点处内侧应力普遍大于外侧应力,钢拱架应力最大值为50.88 MPa,位于边墙处。钢拱架轴力均为负值,表现为受压状态,最大值为-94.25 kN,位于边墙处。钢拱架弯矩自上而下逐步由负值变为正值,最大值为3.22 kN.m,位于拱肩处,稳定后除边墙外弯矩均为负值。通过钢拱架稳定性判断拱顶处稳定性等级为安全,拱肩、拱腰和边墙处为基本安全,施工中应加强观测,减少安全事故的发生。

Study on mechanical properties and stability judgment of steel arch support of TBM tunnel based on field test

Based on the KS tunnel project of the second phase of water supply project in North Xinjiang, through the real-time monitoring of the internal and external flange stress of the steel arch frame and the analysis of its distribution characteristics and change rules, the axial force and bending moment of the steel arch frame are calculated by the principle of mechanics of materials, and the safety level is analyzed by combining the stability judgment process of the steel arch frame. Researches have shown that: The overall performance of the steel arch is in compression state, and the internal stress at the same measuring point is generally greater than the external stress. The maximum stress of the steel arch is 50.88 MPa, which is located at the side wall. The axial forces of the steel arch are all negative value, showing the compression state, the maximum value is -94.25 kN, which is located at the side wall. The bending moment of steel arch gradually changes from negative value to positive value from top to bottom, the maximum value is 3.22 kN. m which is located at the arch shoulder. After stabilization, the bending moment is negative except for the side wall. According to the stability of the steel arch frame, the stability grade of the arch crown is safety, and the basic safety is the arch shoulder, the arch waist and the side wall. During the construction, the observation should be strengthened to reduce the occurrence of safety accidents.