基于D-P准则巷道围岩应变软化与破裂膨胀弹塑性分析

Elastoplastic analysis on strain softening and fracture expansion of roadway surrounding rock based on D-P criterion

为了得到考虑围岩应变软化、破裂膨胀和中间主应力情况下的巷道围岩弹塑性解,基于非关联流动法则和DruckerPrager准则,引入中间主应力系数,建立软化和膨胀模型,得到了巷道变形、破裂区和塑性区半径的解析式,并进行了应用分析。研究结果表明:随中间主应力增大,巷道变形、破裂区和塑性区半径先减后增;围岩软化越严重,对巷道变形、破裂区和塑性区半径影响越显著;软化阶段的膨胀行为对塑性区半径不产生影响,但影响巷道破裂区半径和变形;残余阶段的膨胀行为对破裂区和塑性区半径不产生影响,但影响巷道的变形;巷道变形、破裂区和塑性区半径随支护阻力增大而减小,且原岩应力越大,支护对变形影响越显著。

To obtain the elastoplastic solution of roadway surrounding rock considering the strain softening, fracture expansion and intermediate principal stress of surrounding rock, the softening and expansion model was established by introducing into the intermediate principal stress coefficient based on the non-associated flow rule and Drucker-Prager （ D - P） criterion. The analytical expressions of roadway deformation, radius of fracture zone and radius of plastic zone were derived, and the calcu- lation case and application analysis were carried out. The results showed that the roadway deformation, radius of fracture zone and radius of plastic zone decreased first and then increased with the increase of intermediate principal stress. The higher the softening degree of surrounding rock, the more significant the influence on the roadway deformation, radius of fracture zone and radius of plastic zone. The expansion behavior in the softening stage would not affect the radius of plastic zone, but affect the roadway deformation and the radius of fracture zone. The expansion behavior in the residual stage would not affect the radius of fracture zone and radius of plastic zone, but affect the roadway deformation. The roadway deformation, radius of fracture zone and radius of plastic zone decreased with the increase of support resistance, and the greater the in situ rock stress, the more significant the influence of support on the deformation.