不同含水状态煤-混凝土连接体力学特性和破坏特征

Mechanical properties and failure characteristics of coal-concrete joints in different water-bearing states

对不同含水状态煤-混凝土连接体进行单轴压缩实验和声发射监测,并对连接体力学特性和破坏特征进行探究,研究结果表明:水对煤-混凝土连接体应力-应变曲线特征裂隙压密阶段、破坏阶段和峰后阶段影响明显,水的存在降低了试样间的内聚力,使其脆性降低,塑形增强;含水率增加,煤岩组合体破坏形态由拉伸破坏变为剪切破坏,塑性变形显著;声发射特征曲线与应力-应变曲线对应程度较好,随着含水率的提高,声发射AE计数峰值位置提前,连接体样提前发生结构性破坏。且AE计数峰值数值逐渐减小,连接体样脆性减弱。

After the uniaxial compression experiments and acoustic emission monitoring were carried out on coal-concrete connectors with different water content,and the mechanical properties and acoustic emission characteristics of connectors were explored.The following conclusions can be drawn:water has a significant influence on the compressive stage,failure stage and post-peak stage of the characteristic cracks of the stress-strain curve of the coal-concrete joints.The presence of water reduces the cohesion between samples,reduces the brittleness and enhances the plastic shape.With the increase of water content,the failure mode of coal rock combination changes from tensile failure to shear failure,and the plastic deformation is significant.The acoustic emission characteristic curve corresponds well to the stress-strain curve.With the increase of water content,the peak position of acoustic emission AE count is advanced,and the structural failure of the composite sample occurs in advance.The peak value of AE count gradually decreases and the brittleness of the composite sample decreases.The research results have a certain reference value for the stability of the connection between coal pillar dam and artificial dam of coal mine underground reservoir.