圆形巷道原岩应力对塑性区的影响规律研究

Study on Influence Law of In-situ Stress on the Plastic Zone in Circular Roadway

为研究塑性区围岩应力与原岩应力的关系,将巷道围岩分成塑性残余区、塑性软化区和弹性区,基于Mohr-Coulomb强度准则,考虑扩容和软化特性,计算出了塑性区应力和半径的解析式。通过算例分析了原岩应力对塑性区应力、应变和软化模量的影响。分析结果表明:原岩应力越大,软化区和残余区的范围越大;软化区某点应力减小,而残余区应力几乎不变;原岩应力对软化模量的影响与支护阻力相比小得多;塑性区的径向应变增长速度较环向应变快。研究成果为圆形巷道围岩稳定性和支护设计提供一定的理论依据。

In order to study the relat ionship of surrounding rock stress and in -situstress, the roadway surround-ing rock was divided into plast ic residual zone, plast ic softening zone and elastic zone. Basing on the Mohr-Coulomb strength cri terion , taking the dilatancy and softening properties, the analytic expressions of plast ic zone stress and radius were calculated. In addi t ion , a example was analyzed to study the effect of plast ic zone stress,plastic zone strain and softening modulus. The results shows that the larger the stress of primary roch, the larger the range o f re-sidual zone and softening zone, the smaller stress one po in t in softening zone, but stress o f residual zone is almost same. The effect of in-situ stress on softening modulus is smaller than supporting force. The growth rate o f radial strain is faster than circumferential strain in pastic zone. The study can provide theoretical basis on stability and supporing design of circular roadway surrounding rock.