横观各向同性岩体时效力学特性及支护机理研究

With the increasing development of hydraulic energy, transportation and mineral resources in the west of China, that mechanics properties and supporting mechanism of the transversely isotropic rock under complicated stress conditions has become the focus of the academic researchers’ and engineers’ attention, but here is little systematic research on this respect. This research project will focus on the typical layered rock mass of some major underground construction in the west of China and perform a series of triaxial tests about loading, unloading and creep under different stress conditions, different directions of layer and different stress paths. Based on the experiment research this study will discuss the influence of stress and bedding plane on mechanics properties of rock, propose a three dimensional nonlinear creep model of the transversely isotropic rock, investigate the strength time-dependent evolution equation based on loading rate and put forward a new method of estimating long-term strength. Through anisotropic elastic theory and complex function theory this project will deduce the characteristic function of transversely isotropic surrounding rock and analyze supporting mechanism. Finally the nonlinear creep model of transversely isotropic rock will be programed on the secondary development platform of the commercial software, and based on the field monitoring data back-analysis will be carried out to identify the rheology parameters of surrounding rock through back-analysis, in order to provide the scientific basis for the engineering design, construction and the stability of structure. This research project will have extensive application value and significant economic benefits.

随着我国西部水电、交通以及矿产资源的持续开发，西部复杂地质环境条件下的横观各向同性岩体力学特性及支护机理已成为学术界和工程界关注的焦点，但目前鲜有针对复杂应力条件下横观各向同性岩体的时效力学特性及支护机理方面的系统性研究。本项研究以西部重大工程的层状岩体为对象，开展不同应力状态、应力路径、层理方向条件下岩体的常规三轴加/卸荷和三轴加/卸荷蠕变试验，分析不同地应力特征、岩石层理因素对岩石力学特性的影响，建立横观各向同性岩体的三维非线性蠕变模型；基于加荷速率探讨岩石的强度时效演化方程，提出确定长期强度指标的新方法；采用各向异性理论复变函数推导的横观各向同性岩体洞室的围特征函数，揭示横观各向同性围岩与支护结构之间的相互作用机制；对横观各向同性非线性蠕变模型进行二次开发，结合现场变形监测，反演流变参数，为工程设计、施工及稳定安全性评价提供科学依据，具有广泛的推广应用价值和显著的社会经济效益。

本项目以具有典型层理构造的千枚岩为研究对象，采用室内试验、数值模拟和理论分析相结合的方式，系统研究了横观各向同性（层状）岩体的力学行为包括蠕变特性；考虑加荷速率探讨岩石的强度时效演化过程；基于圆形隧洞模型，采用离散元研究了层理倾向对隧洞围岩变形破坏特性，以及层理滑移面的影响；构建了横观各向同性三维非线性蠕变损伤本构方程，并根据现场监测数据进行了蠕变参数反演，采用数值分析方法论证了千枚岩隧道的长期稳定性。为工程设计、施工及稳定安全性评价提供科学依据，具有广泛的推广应用价值和显著的社会经济效益。