钢管混凝土圆弧拱中性层偏移规律与弯曲破坏机理试验研究

Underground poured concrete-filled steel tubular support(CFST), which is original invention, is a new supporting technology for soft rock roadway in coal mines. It has been used and expanded in more than 20 coal mines. This research is to study the deviation law of neutral layer in the cross section and bending failure mechanism of arch-shaped CFST member under the distributed radial load by the experiments and numerical simulation. Through the tests with different specimens that have different parameters, like reinforcement steel bar, dimenter of steel tube, concrete strength, and so on, It can confirm the plane section assumption is right or not, analyze deviation law of neutral layer in the cross section and the bending failure mechanism, set up the strength calculation theory of arch-shaped CFST member. Due to the effect of neutral layer deviation on the bearing capacity of the member, this research result is conducive to enhance the bearing capacity of CFST support, promote the development of supporting technology of the support, which has important theoretical significance and practical value for the soft rock roadway supporting.

井下灌注式钢管混凝土支架，是深井软岩巷道支护一项重要新技术，属原创性发明，已经在二十多个软岩矿井中推广应用。该项目研究钢管混凝土圆弧拱在径向均布荷载作用下横截面中性层偏移规律与弯曲变形破坏机理。主要采用室内实验与数值仿真方法，进行不同条件下的（如载荷分布、是否抗弯强化、钢纤维掺量等因素）圆弧拱横截面中性层偏移实验测试，实验验证横断面平面变形假设是否成立及其力学条件，分析中性层偏移和弯曲破坏的物理力学机理，建立钢管混凝土圆弧拱弯曲变形强度计算理论。由于圆弧拱中性层偏移直接影响其承载能力，所以该项研究有利于提高钢管混凝土支架的承载能力，能够促进钢管混凝土支架支护理论和技术的发展，对于深井软岩巷道支护具有重要的理论意义与实用价值。

井下灌注式钢管混凝土支架是深井软岩巷道支护的一项重要新技术。本项目以钢管混凝土圆弧拱作为主要研究对象，主要采用室内实验与数值仿真方法，研究在径向均布荷载作用下横截面中性层偏移规律与弯曲变形破坏机理。通过大量的钢管混凝土短柱单轴压缩试验，钢管混凝土圆弧拱六分点加载试验，项目研究了钢管混凝土短柱轴向压缩工作机理，不同钢材线密度钢管混凝土圆弧拱法向均布荷载作用下工作机理，不同直径、壁厚、矢跨比、核心混凝土强度等级和钢纤维掺量钢管混凝土圆弧拱压弯性能。结合试验分析和数值模拟结果，从试件截面强度、局部失稳和整体失稳三方面进行理论分析，给出钢管混凝土圆弧拱局部失稳的原因和承载力计算公式，分析了钢管混凝土的工作机理，实验验证横断面平面变形假设是否成立及其力学条件，分析中性层偏移和弯曲破坏的物理力学机理，建立钢管混凝土圆弧拱弯曲变形强度计算理论，并根据研究成果提出了深埋巷道基于钢管混凝土支架的支护设计方法。能够促进钢管混凝土支架支护理论和技术的发展，对于深井软岩巷道支护具有重要的理论意义与实用价值。