隧道初期支护钢拱架早期承载性能试验研究

Experimental Research on Early Load-Bearing Capacity of Steel Arch for Tunnel Primary Support

为系统分析隧道格栅钢架和型钢钢架支护初期的力学性能,针对三肢格栅钢架、四肢格栅钢架和14号工字型钢钢架开展室内加载试验研究;同时,引入钢材性能系数以直观比较不同类型钢架的综合性能。研究表明:1)在支护初期,格栅钢架与混凝土的结合性能比型钢钢架好,并且在受到集中力影响时,型钢钢架的安全隐患大于格栅钢架;2)钢拱架在实际使用中会受到偏心荷载的不利影响,其中四肢格栅钢架受到的影响最显著,设计时应增加四肢格栅钢架跨中抗扭钢筋布置。

In this study, indoor-loading tests are performed for triangular lattice, tetragonal lattice, and No.14 I-shaped steel arches to systematically analyze the mechanical properties of steel arches. Then, a steel performance coefficient is introduced to comparatively analyze the comprehensive characteristics of various types of steel arches. The research results reveal the following:(1) In the initial stage of tunnel support, the bonding performance between the lattice arch and shotcrete is better than that of the I-shaped steel arch, and the potential safety risk of the I-shaped steel arch is higher than that of the lattice arch under a concentrated force.(2) Steel arch can be adversely affected by an eccentric load in actual service, especially the tetragonal lattice arch. Therefore, increasing the arrangement of torsional reinforcement at the midspan is recommended.