摘要
温度场与应力场是影响碳质千枚岩地层引水隧洞围岩强度的重要因素。设定2因素4水平16组试验,依据单轴与三轴试验结果,探讨热力耦合作用下碳质千枚岩应力-应变曲线性态与破坏模式,得到了峰值强度变化规律;基于Mohr–Coulomb强度准则(M–C)与Heok–Brown强度准则(H–B),分别建立了热力耦合作用下Mohr–Coulomb–Thermal法(M–C–T)和Heok–Brown–Thermal法(H–B–T)两种破坏强度计算方法。试验结果与理论分析表明,随围压增大与温度升高,碳质千枚岩从脆性破坏逐渐转为延性破坏,黏聚力、单轴抗压强度和参数n随温度升高呈线性增大,内摩擦角受温度影响不显著。通过试验值与计算对比分析,M–C–T法和H–B–T法均能较好地量化热力耦合作用下碳质千枚岩强度演化规律;误差分析表明,前者计算误差为-28.5%-7.7%,后者为-8.9%-5.6%,H–B–T法计算结果离散程度较小,稳定性更高,且更偏向于安全。
Temperature field and stress field are important factors that affect the surrounding rock strength of diversion tunnel in carbonaceous phyllite stratum. 16 groups of experiments with 2 factors and 4 levels were set.Based on the results of uniaxial and triaxial tests, the behavior of stress-strain curve and the failure mode of carbonaceous phyllite under thermal mechanical coupling are discussed, and the variation law of peak strength is obtained. Based on Mohr-Coulomb(M-C) criterion and Heok-Brown(H-B) criterion, two calculation methods of failure strength, Mohr-Coulomb-Thermal(M-C-T) method and Heok-Brown-Thermal(H-B-T)method, are established respectively. The experimental results and theoretical analysis show that with the increase of confining pressure and temperature, the failure of carbonaceous phyllite changes from brittle to ductile. The cohesion, uniaxial compressive strength and parameter n increase linearly with the increase of temperature, but the internal friction angle is not affected remarkably by temperature. The results show that both M-C-T method and H-B-T method can quantify the strength evolution of carbonaceous phyllite under thermal mechanical coupling. Error analysis shows that the calculation error of the former is -28.5%-7.7%,and that of the latter is -8.9%-5.6%. The results of H-B-T method show less scattering, hence the method is more stable and more safety oriented.
作者
杨丙昌
YANG Bingchang(The Fivth Project Company Limited of China Railway Bureau 14 Group,Yanzhou 272100,Shandong,China)
出处
《力学与实践》
北大核心
2022年第2期303-309,共7页
Mechanics in Engineering
关键词
热力耦合
碳质千枚岩
强度演化
应力-应变
thermal mechanical coupling
carbonaceous phyllite
strength evolution
stress–strain
