钢管煤矸石混凝土轴心受压承载能力

Axial compression bearing capacity of coal gangue concrete filled steel tubes

针对煤矸石堆积带来的环境污染问题,将煤矸石作为混凝土粗骨料进行资源化利用是合理的解决途径且经济效益显著。将煤矸石作为粗骨料制备钢管煤矸石混凝土,开展轴心受压试验,其中,煤矸石混凝土设计强度等级为C40。探究构件破坏形式与破坏机制及钢管约束作用对核心混凝土强度的提升程度,并根据钢管纵向应变分布研究钢管与煤矸石混凝土之间的黏结应力,分析不同加载方式、径厚比、煤矸石取代率对构件轴压承载力的影响规律。结果表明:加载方式A呈剪切型破坏,加载方式B呈腰鼓型破坏,钢管对煤矸石混凝土具有很好的横向约束;在加载方式A下试件极限承载力高于加载方式B,但加载方式B核心混凝土抗压强度提升更为显著;影响钢管煤矸石混凝土极限承载力的主要因素是取代率,钢管煤矸石混凝土可以很好地弥补煤矸石混凝土自身强度低的特点。

In order to solve the problem of environmental pollution caused by coal gangue accumulation,it is a reasonable solution to use coal gangue as coarse aggregate in concrete for resource utilization with significant economic benefits.In this paper,coal gangue is used as coarse aggregate to prepare coal gangue concrete filled steel tube,and axial compression test is carried out.The design strength grade of coal gangue concrete is C40.The failure mode and failure mechanism of the component and the degree of improvement of the strength of the core concrete by the confinement of the steel tube are explored.The bond stress between the steel tube and the coal gangue concrete is studied according to the longitudinal strain distribution of the steel tube.The influence of different loading methods,diameter-thickness ratio and coal gangue replacement rate on the axial compression bearing capacity of the component was analyzed.The results indicate that loading mode A exhibits shear-type failure,while loading mode B shows waist-drum-type failure.The steel tube provides excellent lateral confinement for the coal gangue concrete.Under loading method A,the ultimate bearing capacity of specimens is higher than under loading mode B,but loading mode B significantly enhances the compressive strength of the core concrete.The primary factor influencing the ultimate bearing capacity of the coal gangue concrete filed steel tube is the replacement ratio.The steel tube coal gangue concrete effectively compensates for the low strength characteristic of coal gangue concrete.