基于塑性区分布形态的软弱破碎巷道围岩控制原理研究

Controlling principles of surrounding rock in soft and broken roadway based on the distribution pattern of plastic zone

以平煤股份六矿北二进风石门软弱破碎巷道围岩为研究对象,采用理论分析、数值模拟和现场实测相结合的方法,分析巷道围岩塑性区分布形态特征,研究侧压系数、内聚力与内摩擦角对塑性区的影响程度。研究结果表明:巷道围岩塑性区主要存在圆形、椭圆形、圆角矩形和蝶形4种分布形态,侧压系数、内聚力与内摩擦角共同影响塑性区的分布形态及其范围;内聚力与内摩擦角对圆形和椭圆形塑性区的影响较小,而蝶形塑性区对内聚力与内摩擦角非常敏感,主要表现为4个蝶叶随内聚力与内摩擦角的增大而快速退化,蝶叶尺寸越大,蝶叶的退化速度越快;提高内聚力与内摩擦角在减小巷道围岩塑性区范围的同时,可促使蝶形塑性区向圆角矩形转化。工程实践结果表明,以中空注浆锚索为核心的“锚网喷+全断面中空注浆锚索”分步联合巷道修复支护技术能够保持软弱破碎巷道围岩的稳定性,保障巷道的长期使用。

With the surrounding rock of the soft broken roadway of wind stone gate in the north of the Sixth Coal Mine of Pingmei Coal Mine as the research object,the distribution characteristics of the plastic zone of the surrounding rock of the roadway has been analyzed through theoretical analysis,numerical simulation and field measurement.The influences of lateral pressure coefficient,the degree of cohesion,and the internal friction angle on the plastic zone have been studied.The results have shown that the plastic zone of roadway surrounding rock mainly has four distribution patterns:circular,elliptic,rectangular,and butterfly;and coefficient of lateral pressure,cohesion and internal friction angle together affect the distribution and range of the plastic zone.The cohesion and internal friction angle have little influence on the circular and elliptic plastic regions,while the butterfly-shape plastic region is very sensitive to the cohesion and internal friction angle,which is mainly manifested in the fact that the four butterfly blades rapidly degrade with the increase of the cohesion and internal friction angle.The larger the size of the butterfly leaf,the faster the degradation of the butterfly leaf.The increase of cohesion and internal friction angle can reduce the range of plastic zone of roadway surrounding rock and promote the transformation of butterfly plastic zone into rounded rectangle in the meantime.The engineering practice results have shown that the multi-step combined roadway repair and support technology,which is based on the hollow grouting anchor cable,can maintain the stability of the surrounding rock of the weak and broken roadway and guarantee the long-term use of the roadway.