软弱煤岩体巷道围岩锚固力衰减特性研究

软弱煤岩体巷道围岩存在强度低、胶结程度差、遇水弱化等特点，正常树脂锚固时出现锚固力低、衰减速度快等问题，易造成巷道围岩严重变形破坏。利用自行研发的锚固孔底单翼倒楔形扩孔装置进行孔底扩孔锚固试验，分析了软弱煤岩体不同锚固状态下锚固力与位移的变化关系。试验结果表明:正常锚固和扩孔锚固状态下脱锚点发生前锚固力与位移曲线表现一致，脱锚点发生后正常锚固状态下残余锚固力瞬间衰减到几乎为0，而扩孔锚固状态下残余锚固力衰减程度较小，并出现残余锚固力大于脱锚力的情况；扩孔锚固状态下脱锚点处扩孔锚固的最大锚固力比正常锚固状态下平均提高2.8倍。软弱煤岩体锚固段发生脱锚界面为锚固剂与孔壁的交界面，脱锚后扩孔段锚固剂对倒楔形孔壁产生挤压破坏，从而提高了软弱煤岩体残余锚固力。试验结果为解决软弱煤岩体巷道锚网支护技术难题提供重要借鉴。

Study on characteristics of anchoring force attenuation in surrounding rock of roadway with soft coal and rock mass

The surrounding rock of roadway with soft coal and rock mass has the characteristics of low strength, poor cementation degree and weakening in case of water, the problems of low anchoring force and fast attenuation speed appear in the normal resin anchor, which is easily to cause the severe deformation and failure in the surrounding rock of roadway. The hole bottom reaming anchor tests were carried out by using the self-developed anchor hole bottom single-wing inverted wedge reaming device, and the variation relationship between the anchoring force and the displacement of the weak coal and rock mass under different anchoring status was analyzed. The results showed that the anchoring force curve was consistent with the displacement curve before the occurrence of anchor off point under the normal anchoring and reaming anchoring status. After the occurrence of anchor off point, the residual anchoring force under the normal anchoring status attenuated to almost zero instantaneously, while the attenuation degree of residual anchoring force under the reaming anchoring status was smaller, and the situation that the residual anchoring force was larger than the anchor off force appeared. The maximum anchoring force of reaming anchoring in the anchor off point under the reaming anchoring status increased by 2.8 times than that under the normal anchoring status on the average. The anchor off interface in the anchoring section of soft coal and rock mass was the interface between the anchoring agent and the hole wall. The anchoring agent in the reaming section after the anchor off produced the crushing failure on the inverted wedge hole wall, thus increased the residual anchoring force of soft coal and rock mass. The results provide important reference for solving the technical problem of anchor nets support in the roadway with soft coal and rock mass.