煤巷顶板厚层跨界锚固原理与应用研究

Research on principle and application of roof thick layer cross-boundary anchorage in coal roadways

深部采动巷道围岩控制是未来锚杆支护重点攻关方向。以葫芦素煤矿3个时期的煤巷为工程背景,通过钻孔窥视分析顶板渐进破坏特征,指出组合支护协同控制不足和施工效率不高的难题。为此提出单一化厚层支护系统,采用离散元数值模拟研究不同长度锚杆支护下巷道位移和围岩裂隙的演化规律,阐明锚杆长度与围岩损伤之间的关联机制;揭示锚杆端头损伤区随锚杆长度增加发生上移并渐进弱化的厚层跨界锚固原理,研发利用长锚杆在顶板及时构建水平和垂向上均能实现应力连续传递的厚层锚固系统和跨界长锚固技术。研究成果在葫芦素煤矿21205工作面开展工业性试验,新技术显著提高煤巷掘进速度,将顶板裂隙发育深度降低至锚固区浅部0.61 m以内,有效遏制了长期存在的大范围"V"型片帮问题,控制了深部复合顶板煤巷围岩大变形。

Surrounding rock control of deep mining roadways is a key research direction of bolt support in the future. Taking the coal roadways of Hulusu coal mine in three different periods as the engineering background,this paper analyzes the characteristics of roof progressive failure through drilling imaging,and points out the problems of insufficient coordination and low construction efficiency of combined support. To better study these problems,a single thick layer support system is proposed. Discrete element numerical simulation is used to study the evolution law of roadway displacement and surrounding rock fractures supported by bolts of different lengths and to clarify the correlation mechanism between the bolt length and the surrounding rock damage. The study reveals the principle of thick-layer transboundary anchoring in which the damage area near the bolt tip moves upward and gradually weakens with increasing the bolt length. A thick layer anchoring system and cross-boundary long anchoring technology are developed to realize continuous stress transmission in both horizontal and vertical directions by using long bolts on the roof in time. The results were applied in the 21205 working face of Hulusu coal mine. As is proved,the new technology significantly improves the driving speed of coal roadways,and reduces the development depth of roof fractures to within 0.61 m of the shallow anchorage zone. Meanwhile,the technology can also effectively curb the long-term large-scale"V"type rib spalling problem and control the large deformation of surrounding rock of coal roadways with deep composite roof.