掘进迎头顶板变形特征及合理空顶距确定方法

Characteristics of roof deformation in excavating face and determination method of reasonable non-support distance

针对掘进迎头附近顶板稳定性影响因素多、空顶距离取值不合理导致掘进速度慢的难题,建立梁结构模型,分析空顶区直接顶下沉规律,并采用数值模拟和响应面法分析影响迎头顶板变形的关键因素及其交互作用关系。结果表明:地质力学环境不变条件下,影响顶板变形破坏的因素中空顶距离最关键,其次是软岩厚度,最后是支护强度。提出通过采用响应面法分析空顶距离、支护强度和岩层结构等关键因素的交互作用来确定最大空顶距离的方法;根据霍尔辛赫矿井条件,空顶距离超过2m且软岩厚度超过2m条件下顶板的下沉较难控制。在霍尔辛赫3603运输巷进行现场应用,将空顶距离定为2 m左右,并提高支护强度至0.1~0.15 MPa后,掘进速度提高约36%,而且巷道整体稳定可控,验证了研究结论的合理性。

In view of the low excavating speed caused by many factors affecting the stability of roof near the heading face and unreasonable permissible non-support distance, a beam structure model has been constructed to analyze the law of immediate roof subsidence. And the key factors causing the roof deformation and their interactive relationship have been analyzed through numerical simulation and response surface method. The results have shown that, among the factors affecting roof deformation and failure, non-support distance is the most critical, followed by the soft rock thickness and the support intensity under the condition of constant geomechanical environment. A response surface method has been proposed to determine the maximum non-support distance through analyzing interaction between several key influence factors such as non-support distance, support strength, and rock structure. And it has also been found that it will be hard to control the roof convergence when non-support distance exceeds m and soft rock thickness is also more than 2 m in the geomechanical environment of Huoerxinhe Coalmine. Conclusion validation and field application have been implemented in transportation gateway 3603 of Huoerxinhe Coalmine. The excavating speed increases by about 36% and the overall stability of the roadway is controllable after the non-support distance is set at about 2 m and the support intensity to is increased to 0.1-0.15 MPa.