构造应力影响下软岩巷道围岩破坏机理及控制技术研究

Study on failure mechanism and control technology of surrounding rock in soft rock roadway under the tectonic stress

针对构造应力影响下软岩巷道持续变形难控制的问题,以发耳煤矿50104运输巷为研究对象,采用现场实测、理论分析和数值模拟等方法,从巷道围岩岩性和应力环境的角度,探究其破坏机理及控制对策。结果表明:低强度软岩加剧了岩体损伤,构造应力孕育了蝶形塑性区,软岩诱发了蝶形塑性区恶性扩展,支护设计缺乏针对蝶叶区域的控制。提出了基于蝶形破坏特征的软岩巷道围岩控制对策—蝶形塑性区靶向加固。其基本科学内涵为支护手段精准介入蝶叶区域,各支护构件协同作用控制蝶形塑性区扩展,提高围岩承载能力;技术关键为锚索与JSMZ20-22新型锚注装置配合使用,实现全长锚固。构建了以“锚网喷+锚注式锚索全长锚固”为核心的蝶形塑性区靶向加固巷道围岩修复方案。现场监测结果表明:顶底板最大移近量为158 mm,两帮最大移近量为121 mm,蝶叶塑性区未出现进一步扩展,巷道围岩变形破坏得到了有效控制。

To effectively control the continuous deformation of the surrounding rock in the soft rock roadway under the tectonic stress,the failure mechanism of the surrounding rock and its control measures for the haulageway 50104 in the Fa、er Coal Mine was investigated from the perspective of rock lithology and stress environment through the field measurement,theoretical analysis,and numerical simulation.The results indicate that:since the low strength of soft rock exacerbates rock damage,tectonic stress fos⁃ters the development of a butterfly⁃shaped plastic zone;soft rock further induces the sudden,rapid and contentious expansion of this plastic zone,and support design lacks control over the butterfly⁃shaped plastic zone.Additionally,the control measures for the surrounding rock with butterfly⁃shaped failure characteristics in the soft rock roadway were proposed,that is,the targeted reinforcement for the butter⁃fly⁃shaped plastic zone.Specifically,the precise support methods were employed for the butterfly⁃shaped zone,and the coordinated action of various support components was used to control the expansion of the butterfly⁃shaped plastic zone to improve the bearing capacity of the surrounding rock.The key of the tar⁃geted reinforcement for the butterfly⁃shaped plastic zone was the joint application of the anchor cable and the JSMZ20⁃22 new anchor injection device to achieve full⁃length anchoring.Additionally,a butterfly⁃shaped plastic zone targeted reinforcement for the roadway surrounding rock repair was constructed with the core of"anchor net spraying+anchor⁃injection cable(full⁃length anchoring)".The on⁃site monitoring results show that the maximum displacement of the roof and floor was 158 mm,and the max⁃imum displacement of the two sides was 121 mm.Furthermore,no further expansion was observed in the butterfly⁃shaped plastic zone,and the deformation and damage of the roadway surrounding rock were ef⁃fectively controlled.