高垂直应力状态下巷道围岩分区破坏特征试验研究

通过自行研制的CM60/10平面应变试验台配合三轴伺服试验机,发挥伺服稳压性能,采用相似材料模拟配合数值模拟验证的手段,分析了高地应力λ<1状态下无支护巷道围岩破坏过程及特征。试验结果表明:1)破坏首先发育在巷道两帮中线,局部破坏产生后,逐渐形成一对"楔形"破坏区域。在应力卸压区内,围岩呈分区破裂形式。深部滑移线由"楔形"破坏区域尖端点处开始延伸,基本符合对数螺线形式;2)巷道破坏过程中,依次出现"楔形破裂带","二次破裂带""贯通失稳带"3个过程分区。研究指出此类地应力下不同变形时期内,除控制顶底板初始变形外,围岩裂隙控制的重点应依次在巷道两帮、肩部和底角、顶板;3)通过对λ<1状态下围岩破坏的数值模拟发现:两帮围岩垂直应力呈"波浪状"分布,塑性破坏区呈"分区演化",垂直位移呈"锯齿状"分布,与物理试验基本吻合。

Experimental Research on the Failure Characteristics of Surrounding Rock Under High Vertical Ground Stress

By using independent researched and developed CM60/10 plane strain test-bed,combining with the triaxial servo test machine which playing the servo regulator performance,utilizing similar material simulation and numerical simulation,the characteristics of deformation and failure process of roadways with no support under high stress of λ<1 state was analyzed.The results show that: 1) The destruction develops first from the center line of both sidewalls of roadway,after the local failure,there gradually formed a pair of "wedge" failure zone.In the stress relief area,surrounding rocks are de-stroyed in the form of zonal disintegration.Deep slip-line takes place from the tip point of the "wedge" destruction zone,which conforms to the logarithmic spiral line roughly;2) In the process of roadway destruction,it is followed successively by three partitions of "wedge-shaped destruction zone," "second destruction zone," "transfixion instability zone".The related studys show that during the different de-formation period in this kind of ground stress,the failure control should focus on the sidewalls,the skewback and the roof except the control of the initial deformation of roof and floor;3) Through the numerical simulation of the rock mass failure in λ<1 state,the following results can be found: the ver-tical stress of the sidewalls is the "wave-like" distribution;the plastic damage zone is "partition evolu-tion";the vertical displacement is "jaggies-like" distribution.All of these are consistent with the physi-cal experiments.