地下矿山大断面软弱围岩硐室变形机制与支护方法研究

大断面破碎软弱围岩硐室的支护一直是地下矿山开采的难题。基于此,本文以贵州烂泥沟金矿硐室大变形为工程背景,通过现场实测资料、采用理论计算和地质环境分析,揭示了底板和两帮变形机理:巷道在垂直及水平高应力作用下,呈现由两组优势节理组成的菱状空间破裂特征,在采动爆破震动影响下,围岩应力二次分配,使塑性区持续向深部拓展,降低了支护锚固力效果,从而导致围岩变形严重。基于支护理论,本文提出了顶板采用补强锚索+注浆+喷锚网,两帮采用补强树脂锚杆+锚索+壁厚注浆+喷锚网,底板采用反拱+注浆的联合支护方式。现场实测表明,这种联合支护方式与原始支护方式相比,对硐室长期稳定性控制具有良好效果。该研究可为深部复杂地质条件下的巷道变形加固提供借鉴。

Study on deformation mechanism and supporting method of large section soft surrounding rock chamber in underground mine

The support of large-section broken and weak surrounding rock chambers has always been a problem in underground mining. Based on the tickler, this article takes the large deformation of the chamber of the Lannigou gold mine in Guizhou as the engineering background. Through field measurement data, theoretical calculations, and geological environment analysis, it reveals the deformation mechanism of the floor and sidewalls: under high vertical and horizontal stress, the roadway presents the characteristics of a diamond-shaped spatial rupture composed of two sets of superior joints. Under the influence of mining blasting vibration, the stress of the surrounding rock is redistributed so that the plastic zone continues to expand to the depth, reducing the effect of supporting and anchoring force, resulting in serious deformation of the surrounding rock. Based on the support theory, this paper proposes that the roof adopts reinforcement anchor cable, grouting, and spray anchor net, the two sides adopt reinforcement resin anchor rod, anchor cable, wall thickness grouting, and spray anchor net, and the bottom plate adopts reverse arch, and grouting. According to the combined support method, the field test shows that this combined support method has a good effect on the long-term stability control of the chamber compared with the support method before. This research can provide a reference for the deformation and reinforcement of roadway under complicated deep geological conditions.