隧道型钢钢架初期支护安全性评价

针对施工期隧道型钢钢架喷混凝土支护，建立了以位移为基础的安全性评价方法.介绍了根据喷混凝土徐变试验得到的修正的GL2000徐变模型，给出了徐变引起的支护轴向伸缩变形和曲率改变的计算公式.导出了基于测量位移并考虑徐变影响的支护内力的计算公式，给出了支护结构截面失效的功能函数.最后，对武广铁路某隧道工程进行了实例分析.计算结果表明:评价结果能够正确反映隧道的实际安全状态，可靠指标的数值与我国现行规范的规定一致；徐变使喷层产生松弛，可靠指标增大，但其增大幅度比素喷混凝土和格栅钢架喷混凝土时小. 

Assessment on Safety of Steel Reinforced Shotcrete Support for Tunnels

A displacement-based method was proposed to evaluate the safety of steel reinforced shotcrete support for tunnels under construction. Based on shotcrete creep experiment, a GL2000 model was modified and employed to describe the creep of shotcrete. Formulas to calculate the axial deformation and curvature change of the support were obtained. Formulas to compute the internal forces of the support with creep considered were given, and performance functions to a cross-section of the support were put forward. At last, a case study was done for a tunnel on the Wuhan-Guangzhou railway line. The case research result shows that results based on the proposed method are consistent with in-situ situations. Calculated reliability indices fall into the interval required by the related Chinese codes. Creep causes the shotcrete to relax to result in large reliability indices, but the increase of the indices is smaller than those for plain shotcrete and lattice girder reinforced shotcrete supports.