在相似模拟试验中利用超声波检测技术探测底板破坏深度

Ultrasonic Testing of Floor Breakage Depth on Similar Simulation

随着矿井开采深度的增加,工作面底板承压含水层水压也逐渐升高.为了更深入研究承压开采工作面底板破坏规律,以赵固二矿11050工作面为原型,进行了相似模拟试验,以石膏块模拟底板L8灰岩,监测底板应力和位移.将超声波检测技术应用于底板岩层结构破坏分析上,探测回采前后物性变化,并结合岩体内部波速与力学特征的关系,给出底板岩体破坏的判断标准.结果表明随着工作面推进,底板裂隙逐渐发育,在工作面后方20m范围内,底鼓量最大,且位移曲线与应力曲线基本吻合;超声波探测最终确定底板破坏深度为28～32m,与现场实测结果一致.

Withmining depth increasing,the water pressure of floor confined aquifer increases. In order to study further on floor breakage law,this paper takes Zhaogu NO. 2 mine 11050 working face as the prototype. The similar simulation test was carried out. With gypsum block simulating L_8 limestone,the stress and displacement was monitored. Ultrasonic testing was applied to analysis on structural damage of floor. By testing physical properties during mining,and combining the wave velocity to themechanics feature of rock,the floor breakage criterion was given. The results show that: within 20 m behind working face,the displacement of floor is the biggest,and displacement curve accords with stress curve. By ultrasonic testing,the floor breakage depth was 28 ~ 32 m,which was consistent with the measured results.