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深部高应力富水黏土软岩大巷底鼓机理及控制技术

Mechanism and control technology of floor heave in deep high-stress water-rich clay soft rock roadway

  • 摘要: 为研究深部高应力富水黏土软岩大巷强烈底鼓控制技术,以陕西蒋家河煤矿二采区回风大巷为工程背景,理论分析了大巷底鼓影响因素,采用UDEC-Trigon离散元方法研究了大巷变形破坏特征及底板锚注支护机理;研发出适合于富水条件下锚杆(索)锚固的新型耐水锚固剂,并在井下取得良好锚固及拉拔效果;提出了先注浆封闭裂隙、后锚索加固的底鼓控制方案,并成功应用于工程实践。研究结果表明:大巷在高应力及水理作用影响下呈挤压流动性和水理膨胀性底鼓;锚注支护对于减小深部高应力围岩塑性区分布作用不明显,其主要作用在于控制底板围岩浅部张拉裂纹的产生和深部剪切裂纹的产生、扩展延伸及贯通,抑制导水裂隙带形成,避免围岩遇水泥化弱化岩体强度,底板锚索支护系统还可有效改善底板围岩应力状态,避免浅部近零应力区形成及深部围岩应力的进一步释放;锚注支护加固底板后,锚索支护系统与底板围岩系统处于稳定状态,实测大巷最大底鼓量仅202 mm,有效解决了深部高应力富水黏土软岩强烈底鼓问题。

     

    Abstract: In order to study the strong floor heave control technology of deep high-stress water-rick clay soft rock roadway, the floor heave mechanism of the main return roadway in the second panel area of Jiangjiahe coal mine was analyzed theoretically. UDEC-Trigon discrete element method was used to study the deformation and failure characteristics of the main roadway and the joint support mechanism of the floor bolting and grouting support. The deformation and failure characteristics of the main roadway and the mechanism of the floor bolting and grouting support have been studied. A new type of water-resistant anchoring agent suitable for anchoring bolts (cables) under water-rich conditions has been developed through laboratory experiment, and good results were achieved on site. Floor heave control scheme of grouting closed crack and anchor cable reinforcement was proposed and successfully applied in engineering practice.The research results show that the main return roadway exhibits squeezing fluidity and hydrodynamic expansion floor heave mechanism under the influence of high stress and hydraulic effects, and bolt-grouting support has no obvious effect for reducing the distribution of plastic zone in deep high stress surrounding rock, but can significantly control the generation of tensile cracks in the shallow part and the generation, extension and propagation of deep shear cracks to inhibit the formation of water-conducting fracture zones, and to prevent the surrounding rock from weakening the strength of the rock mass due to cementation. It can effectively improve the stress state of the surrounding rock of the floor, avoid the generation of near-zero stress regions in the shallow part and further release of deep surrounding rock stress. After the anchor-grouting support strengthens the floor,the anchor cable support system and the surrounding rock system of the floor are in a stable state, and the maximum floor heave of main return roadway is only 202 mm, which effectively controls the strong floor heave problem of deep high stress water-rich clay soft rock.

     

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