考虑渗流、应变软化和扩容的巷道围岩三剪应力统一强度理论解

Three-shear Stress Unified Strength Theoretical Solution on Surrounding Rock of Roadway Considering Seepage,Strain Softening and Dilatancy

为了研究渗流、应变软化和扩容对巷道围岩稳定性的影响,首先根据三剪应力统一强度理论建立了平面应变状态下的屈服方程,将巷道围岩从外往内依次划分为弹性区、塑性软化区、破碎区,然后综合考虑渗流影响、应变软化、扩容以及塑性软化区和破碎区内弹性应变的2种情况,推导了各个区应力、位移以及塑性软化区和破碎区半径的三剪应力统一强度理论解,最后探讨了塑性软化区和破碎区弹性应变不同取值、孔隙水压力、软化模量、扩容系数对巷道围岩塑性软化区、破碎区位移和半径的影响。研究结果表明:1)应优先采用由广义胡克定律即情况2来确定塑性软化区和破碎区弹性应变比较合理;2)孔隙水压力对塑性软化区、破碎区位移和半径影响显著;3)软化模量对塑性软化区半径无影响,对塑性软化区和破碎区位移影响很小,对破碎区半径影响显著;4)不同扩容系数对塑性软化区半径无影响,对塑性软化区和破碎区位移、破碎区半径影响显著,应采用非关联流动法则对扩容进行分析。

In order to study the influence of seepage,strain softening and dilatancy on the stability of road-way surrounding rock,firstly,the yield equation in plane strain state was established according to the three-shear stress unified strength theory.The roadway surrounding rock was divided into elastic zone,plastic softening zone and fracture zone from outside to inside,and then the influence of seepage,strain softening,dilatancy coefficient and elastic strain in plastic softening zone and fracture zone of two kinds of circumstances were comprehensively considered.The unified strength theoretical solutions of stress,displacement and the radius of plastic softening zone and fracture zone in each zone were derived.Finally,the effects of different values of elastic strain,pore water pressure,softening modulus and dilatancy coefficient on the displacement and radius of plastic softening zone and fracture zone of roadway surrounding rock were discussed.The results showed that:1)It is reasonable to determine the elastic strain of the plastic softening zone and the fracture zone by the generalized Hooke s law,that is,case 2.2)The pore water pressure has a significant effect on the displacement and radius of the plastic softening zone and the broken zone.3)The softening modulus has no effect on the radius of the plastic softening zone,but has little effect on the displacement of the plastic softening zone and the fracture zone,and has a significant effect on the radius of the fracture zone.4)Different dilatancy coefficients have no effect on the radius of plastic softening zone,but have significant influence on the displacement and radius of plastic softening zone and fracture zone,so the unrelated flow rule should be used to analyze the dilatancy.