高应力软岩巷道围岩塑性区恶性扩展过程及其控制

以曲江煤矿-850 m东大巷延伸段深部高应力软岩巷道为工程背景,采用理论分析、数值计算、现场试验等手段,分析了高应力软岩巷道围岩塑性区的产生、形成过程。塑性区的发展一般经历5个阶段,即塑性点的出现、塑性环的形成、塑性环局部畸变、塑性区非均匀扩展、塑性区恶性扩展等。认为巷道围岩失稳主要是塑性环的局部畸变导致了塑性区的恶性扩展所致,要控制巷道围岩稳定,关键对策是控制塑性环的局部畸变,其次是控制塑性区的恶性扩展,使围岩塑性区尽可能均匀缓慢发展。根据塑性区控制原理,提出了"锚网索喷+底板锚索+局部锚索或注浆加强"的支护方案并在该巷道实施。数值计算表明,该巷道塑性区总体均匀发展,没有发生恶性扩展。现场监测结果显示,所采用的支护方案较好地控制了围岩。

Malignant development process of plastic zone and control technology of high stress and soft rock roadway

In the extended segment of -850 m main haulage way of Qujiang Mine,the development processes of plastic zone in soft rock roadway with high geo-stress has been analyzed by theoretical analysis method,numerical simulation method and other techniques.The five development stages of plastic zone take place successively,which are plastic dot,the formation of plastic annulus,the distortions of plastic annulus,the uneven development and malignant extension of plastic zone,respectively.The studies suggest that the partial distortion of plastic zone is a major cause for the malignant extensions of plastic zone.Only effectively control the partial distortion of plastic zone,and make the development of plastic zone tend to uniform as much as possible,then the stability of surrounding rocks would be achieved.According to the plastic zone control theory,the comprehensive support method with “bolt wire cable and shotcrete+floor anchor cable+local anchor cable or grouting reinforce” is presented and applied in the roadway.The monitor result at construction site shows that the general development of the plastic zone is uniform and the deformation of the surrounding rock is controlled well by the supports applied.