冲击地压巷道围岩改性研究

Study on Surrounding Rock Modification of Rock Burst Roadway

针对巷道围岩改性的研究,主要采用理论解析及室内试验相结合的方法,先分析改性前影响围岩塑性区范围的因素,再利用试验研究改性后不同时间段内试件的力学特性及声发射特征,通过抗压、抗拉、抗剪、声发射实验手段研究围岩改性体破裂力学显现过程。结果表明:改性前围岩塑性区范围受支护阻力、侧压力系数、软化系数、扩容梯度及残余强度等参数的影响;其他条件一定时,提高围岩破碎区的残余强度可减小围岩塑性区的范围;改性体7 d、14 d、28d的抗压强度逐渐增加,最终达到原煤样强度的48.95%,28天的抗拉强度达到原煤样强度,黏聚力与完整煤样相比提高了2.05倍,对围岩塑性圈的改良均有很好的效果;声发射研究得到:7 d、14 d改性体试件的声发射信号变化较强烈,且在各个阶段都有大量的声发射信号产生,在受力情况下试件内部情况复杂,而28 d改性体的声发射信号变化较稳定,主要集中在破坏前后,在时间的作用下改性体的破坏形式逐渐由延性破坏转变为脆性破坏,证明28 d后改性体的强度达到饱和值,在围岩改性强度稳定后才能发现再次进行施工。根据实际情况制定围岩注浆改性方案,并监测围岩顶底板及两帮的移近量,改性后的围岩稳定性增加,变形量减小。

In view of the research on the modification of roadway surrounding rock,the combination of theoretical analysis and laboratory test is mainly used to theoretically analyze the factors affecting the plastic zone range of surrounding rock before modification.The mechanical properties and acoustic emission characteristics of the specimens in different time periods after modification were studied by experiments.The fracture mechanics of the surrounding rock modified body was studied by compressive,tensile,shear and acoustic emission experiments.The results show that the range of plastic zone of surrounding rock before modification is affected by parameters such as support resistance,lateral pressure coefficient,softening coefficient,dilatancy gradient and residual strength.The results show that the range of plastic zone of surrounding rock before modification is affected by parameters such as support resistance,lateral pressure coefficient,softening coefficient,dilatancy gradient and residual strength.When other conditions are certain,increasing the residual strength of the surrounding rock crushing zone can reduce the range of the surrounding rock plastic zone;the compressive strength of 7 days,14 days and 28 days of the modified body gradually increased,and finally reached 48.95% of the strength of the original coal sample.The tensile strength of 28 days reached the strength of the original coal sample,and the cohesion was increased by 2.05 times compared with the complete coal sample,which had a good effect on the improvement of the plastic zone of the surrounding rock.The acoustic emission research shows that the acoustic emission signal of the modified body specimen changes strongly at 7 days and 14 days,and a large number of acoustic emission signals are generated at each stage.The internal situation of the specimen is complex under the force condition,while the acoustic emission signal of the modified body at 28 days is relatively stable,mainly before and after the failure.Under the action of time,the failure mode of the modified body gradually changes from ductile failure to brittle failure.It is proved that the strength of the modified body reaches the saturation value after 28 days,and the construction can be carried out again after the strength of the surrounding rock is stable.According to the actual situation,the grouting modification scheme of surrounding rock is formulated,and the displacement of the roof and floor of the surrounding rock and the two sides is monitored.The stability of the modified surrounding rock increases and the deformation decreases.