Control technology for floor heave of Jurassic soft rock in the Erdos Basin of China: A case study

The deformation of soft rock roadway caused by floor heave is a major challenge for coal mines in China western mining areas. To achieve security and stability of soft rock roadway, this work considered the headgate at panel 11505 of the Yushujing Coal Mine as background. First, based on the limit equilibrium method and slip line field theory,a model of floor heave was established, the mechanism of floor heave control was analyzed, and an optimized support method was proposed. Then, the displacement, stress and failure zones around the surrounding rock with the original and optimized support were studied by FLAC. Finally, the serviceability of the support method was verified by field application. The results showed that the main deformation form of soft rock roadway is floor heave, and 0.5 m is relatively reasonable thicknesses of the inverted arch. The extrusion failure zone and shear failure zone were mainly affected by tensile and shear failure, respectively. The modification of floor and the effective support are key points. The failure zone was consistent between numerical simulation and theoretical calculation. The maximum convergences of floor heave determined by numerical simulation and field measurement were 220 mm and 240 mm, respectively, which were reduced by 55% and 60% compared with the original support, and the convergence between sidewalls decreased considerably. The optimized support method controls the floor heave well.

巷道底臌机理的研究

底臌一直是煤矿软岩巷道支护中难以解决的问题之一，但迄今为止人们对巷道底臌的机理尚无统一的认识。只有正确认识了底臌的机理才能建立反映实际的力学模型进行有效的数值计算。在大量现场研究、实验室模型试验和数值计算的基础上，全面讨论了煤矿巷道的底臌特征及其机理，分析了影响底臌的主要因素，为在不同的矿山地质条件下采取有效的防治巷道底臌的措施和进行正确的力学数值计算提供了依据。

深部岩石巷道底鼓流变分析

利用凯尔文模型的黏弹性理论研究了深部岩石巷道出现的底鼓问题,进行了流变分析,给出了深部岩石巷道底鼓现象的时间—位移解析解,提示了深部岩石巷道底鼓现象时间演化过程的一些规律。在巷道不支护状态下,研究巷道开挖后约150 h位移曲线才逐渐趋于收敛。研究成果对深部岩石巷道底鼓现象的治理具有一定的指导意义和参考价值。

深部软岩巷道底臌流变变形分析

深部软岩巷道的底臌量具有时间效应,巷道开挖后,其底板位移量由巷道底板产生的瞬时弹性变形和流变变形组成。根据黏弹性Burgers流变模型对巷道底板进行流变分析和研究,推导出巷道底板在流变作用下位移量随时间变化的函数u(t)。结合工程实例,采用FLAC^3D数值模拟软件对玉华煤矿2401运顺掘进工作面进行数值模拟分析,得出不同时间由于流变而引起的巷道底板的位移量,并根据数值模拟结果和推导函数u(t)反算出蠕变参数,现场观测结果表明,由于流变因素产生的底臌量占巷道总底臌量的37.97%;在巷道开挖60d以后,底板的位移量才逐渐达到收敛状态,这对深部软岩巷道底臌现象的治理具有重要指导意义。

深埋大采高综采面采动巷道底鼓机理及控制研究

围岩稳定性是影响煤矿巷道正常使用的关键,巷道底鼓是制约矿井高产高效的关键因素之一。以宁东矿区梅花井煤矿232204辅运顺槽地质条件为背景,采用现场调研、理论分析、数值模拟的方法研究了巷道底鼓机理。研究发现巷道底板无支护和采动影响是巷道底鼓的根本原因,在原支护条件下巷道围岩呈不均匀收缩状态,顺槽发生挤压流动型底鼓。提出了巷道优化支护方案并进行验证。结果表明:巷道底板最大破坏深度为3.2 m,优化支护后,巷道底鼓量由原支护条件下的1150 mm减小到350 mm,两帮对底板软岩产生的“挤压”效应得到了有效缓解,整体围岩系统在“顶-底-帮”优化支护后能实现长期稳定。

煤层群底部巷道围岩破坏机理及控制技术

针对山西大同晋华宫煤矿11^#煤层8714工作面运输巷在掘进期间出现片帮、底鼓等严重矿压显现现象,采用理论分析和数值模拟等方法,探讨了煤层群底部煤层巷道围岩变形破坏机理,并提出了相应的控制技术。

高应力软岩斜巷底鼓机理及全断面注浆技术

为了控制巷道围岩稳定性,提出巷道全断面注浆锚固技术。通过理论研究、数值模拟与工程实践,分析巷道底鼓破坏机理并确定最佳支护方案。研究表明:高应力软岩倾斜巷道底鼓是由于帮部岩层滑移后释放内部弹性势能,造成巷道底板岩层弹、塑性势能大量积聚,采用拱形巷道断面及全断面注浆方式,有效控制了巷道底鼓的持续增长,巷道顶板及两帮围岩大变形也得以全面控制,保证了巷道围岩的稳定性。