以广西百色东笋煤矿为工程背景,针对力学强度较低的半煤岩巷道难支护问题,采用现场调查、室内试验、岩体测试与监测、数值计算、理论分析和工业试验等手段进行变形机制和控制技术等研究。首先,通过巷道变形情况的调查发现,东笋矿区半煤岩巷呈现大变形特点,变形主要出现在巷道的两帮,以中下部最为严重;进行围岩裂隙窥视与实验室力学试验,可知,巷道岩体强度较低,遇水崩解、膨胀,松动圈可达到4m左右。然后,分析岩煤巷道破坏的主要原因与变形特点,认为支护失效与巷道失稳的主要路径为:围岩强度较低-节理裂隙发育(外界环境及扰动作用下)-碎胀变形-应力叠加及流变-大变形;最后,分析该类巷道的支护原理,提出以“桁架锚索”为核心的“锚、网、索、梁”综合支护技术。理论分析表明关键在于帮部的支护,即桁架锚索,桁架锚索既起到力传递作用,又增大帮壁煤岩体的受力面积,提高支护刚度。根据煤岩体变形与桁架锚索受力特点,设计一种反扣装置,该装置能提高锚索桁架钢的抗弯矩能力。应用表明,该综合支护技术能发挥“固帮”“强顶”和“抑底”等作用,从而达到全方面地提高巷道的稳定性。
Abstract: The large deformation characteristics of half coal rock roadway in Dongsun Coal Mine was found through a large number of deformation survey. The deformation occurred mainly on two sides of the roadway especially at the lower part of the sides. The rock fractures were inspected and the laboratory tests were conducted. The roadway rocks were found to have low strengths, to swell and even to be disintegrated by water and to have the diameter of loosen circle about 4 m. The main reasons for the damage of rock-coal roadway and the instability and the failure of roadway support were found to be the lower strength of rock and the developed rock joints and fissures(under the action of the external environment and disturbance) leading to the expansion and crushed deformation together with the stress superposition and rock creeping leading to the large deformation. A supporting system with the anchor, nets, cables and beams around key structures of the truss and anchor rope was proposed according to the roadway supporting principle. Theoretical analysis shows that the side supporting,namely the truss and the anchor rope are very important in transmitting forces and increasing the force carrying area of two side coal walls and thus improving support capacity. A buckle device was designed based on the mechanical characteristics of the truss, the anchor rope and the coal and rock deformation, which can improve the capacity of bending resistance of truss and anchor rope. The application of the system showed that it could stabilize the side wall, strengthen the roof and restrain the floor heave etc. to achieve an overall improving of the stability of roadway.