摘要
考虑中间主应力、脆性软化、剪胀特性、塑性区弹性模量及弹性应变定义等综合影响,提出深埋圆形巷道弹塑性计算的基本假定,进而建立围岩塑性区位移及特征曲线新解,对其进行可比性分析与比较验证,并详细探讨各因素影响特性。所得围岩塑性区位移及特征曲线新解是不需要借助任何数值算法的理论解析解,具有广泛的适用性和很好的可比性。研究结果表明:巷道结构的强度理论效应即中间主应力影响显著,相应的支护可以减弱或改用轻型支护;不考虑脆性软化或剪胀特性都将低估围岩实际位移,工程设计偏危险;半径相关的塑性区弹性模量得到的围岩变形及特征曲线处于上、下限之间,能体现巷道开挖卸载受扰程度的距离渐进性变化;塑性区弹性应变应优先选用更合理和准确的第三定义,且各因素之间存在相互影响。
Taking comprehensive influences of intermediate principal stress, brittle softening, dilation characteristic, Young＇s modulus and elastic strains in the plastic zone into account, some basic assumptions are proposed for the elastoplastic calculation of a deep circular tunnel. On the basis of these assumptions, the new solutions of rock plastic displacement and ground response curve are derived; and then feasibility analysis and comparative verification of the new solutions are carried out. Parametric studies are discussed in detail. The rock plastic displacement and ground response curve presented by this study are theoretical analytical solutions without the need for any numerical method and have broad applicability as well as good comparability. It is found that the strength theory effect of a tunnel, i.e. the intermediate principal stress effect, is significant and the corresponding weak support or light support can be used; the ignorance of brittle softening or dilation characteristic will underestimate actual tunnel deformation, and hence less safety in engineering design; the rock deformation and ground response curve according to the radius-dependent Young＇s modulus are between the upper and lower bounds, which can reflect gradual change of the tunnel excavation unloading effect with distance; the third definition for elastic strains in the plastic zone is preferred for its reasonability and precision, and there are interactions between different factors.
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2016年第1期12-24,32,共14页
Rock and Soil Mechanics
基金
国家自然科学基金项目(No.41202191)
中国博士后科学基金项目(No.2014M562358)
陕西省自然科学基础研究计划项目(No.2015JM4146)
陕西省博士后科研项目~~
关键词
收敛约束法
围岩特征曲线
中间主应力
脆性软化
剪胀特性
塑性区弹性模量
塑性区弹性应变
convergence-confinement method
ground response curve
intermediate principal stress
brittle softening
dilation characteristic
Young＇s modulus in the plastic zone
elastic strains in the plastic zone
