循环温度作用下石膏矿岩强度劣化效应试验研究

Experimental study on strength weakening effect of gypsum mine rock under circu-lating temperature

为研究循环温度对石膏矿岩的影响,采用波速表征石膏矿岩的完整度、单轴抗压强度表征石膏矿岩的强度劣化效应,开展循环温度作用下石膏矿岩强度劣化效应试验。结果表明:随着循环温度次数增加,石膏矿岩波速整体呈现平→急→波动→稳的变化规律,完整度最大降低率为27.3%,证明循环温度作用可造成石膏矿岩内部结构的变化和损伤;随着循环温度次数增加,石膏矿岩应力-应变曲线的压密阶段时间增长、弹性阶段时间减少、塑性阶段时间增加、峰值强度对应的应变增大,强度整体呈降低趋势,最大强度劣化率为12.60%,证明循环温度对石膏矿岩强度有劣化效应。研究成果对揭示石膏矿大面积采空区坍塌机理和防控具有一定的理论指导和借鉴意义。

In order to study the influence of circulating temperature on gypsum rock,experiments were car-ried out to reveal gypsum rock strength weakening with wave velocity representing integrity and uniaxial compressive strength representing strength weakening.The results showed that:With the number of circulat-ing temperature increasing,the wave velocity showed out the law of“gentle-sharp-fluctuate-stable”,and the integrity decrease rate of gypsum rock was 27.3%,which verified that circulating temperature induced micro-structure change and damage to gypsum rock.With the number of circulating temperature increasing,the stress-strain curve of gypsum rock showed out compaction stage growing,elastic stage shortening,plas-tic stage increasing and strain of peak strength increasing,the peak strength was decreasing,and the biggest decreasing rate was 12.60%,which verified that the circulating temperature induced strength weakening ef-fect of gypsum rock.The research results had theoretical guidance and reference significance to reveal the collapse mechanism of large gypsum goaf and its control.