多组节理岩体洞室的蠕变特性及其粘弹塑性效应

本文在岩体节理面剪切蠕变试验和完整岩石扭转蠕变试验的基础上,探讨了多组节理岩体的剪切变形规律、各向异性性态及其时间效应,用试验论证了对节理面采用所建议的“弹-粘塑性”力学模型的正确性,分别推导了在不同应力状态下节理面、完整岩石和多组节理岩体粘塑性应变速率的计算公式,提出了节理岩体大断面洞室考虑分步开挖和不同支护时间的粘弹塑性有限元数值方法.通过对某地下工程实例的计算,得出多组节理岩体洞室稳定的定景分析和评价,以及工程设计和施工的若干合理化建议.

The Reological Characteristics of Tunnel Opening in Multi-Laminate Joint Rock Mass and Its Viscous Elasto-Plastic Effects

On the basis of creep tests of joint surface as well as intact ruck, the shear deformation rule, anisotropic rheological behaviour and time dependent effect of multi-laminate rock mass are discussed. The validity of the elastic viscoplastic mechanical model to describe the joint behaviour is proved by laboratory tests. The paper derives detailly the viscoplastic strain velocities of joint, intact rock, as well as multilaminate rock mass corresponding to different stress states, and presents a viscous elastoplastic F. E. M. with consideration of the stepwise excavation sequence and different supporting time of lining in underground works with large cross-section. By the quantitative analysis and evaluation of a tunnel opening in multi-laminate rock mass, the rational proposals for the excavation and construction of underground structure are suggested. The computation shows that the present research work has a valuable technical significance and economical benefit in engineering practice.