基于三维损伤流变理论下某调压井群围岩时效稳定性研究

拟建的某水电站调压井区域围岩岩性为石英云母片岩，勘探及室内试验发现其岩体属于片理构造发育明显的软岩，具有较典型的横观各向同性流变特征。由于区域地应力水平较高，工程施工期及运行期围岩流变现象可能显著影响岩体稳定性及衬砌结构特性。本文在全面反映区域地质构造、调压井结构形式及地应力场的基础上，建立了三维数值计算模型，同时考虑施工时序及支护衬砌措施，应用根据室内试验及现场监测资料建立的横观各向同性岩体粘弹塑性损伤本构模型，采用FLAC3D软件研究了调压井群施工期和运行期围岩稳定性及衬砌结构安全性。结果表明：施工开挖过程中围岩在流变效应的显著影响下，其变形量随时间有所增加，及时喷锚支护对围岩变形的限制作用显著，开挖完成后500d后围岩位移趋于收敛；开挖完成后围岩整体处于受压状态，施作二次衬砌有利于围岩应力场均匀化重新分布；运行期调压井衬砌变形量值增长速率随时间逐渐减小，其中2年内变形量约占长期（50年）变形量的54%，调压井围岩及衬砌结构运行1年后应力水平基本趋于稳定，运行期内调压井围岩应力水平变化幅度很小。

Study on the aging stability of the surrounding rock of a surge-shaft group based on three dimensional damage rheological theory

The surrounding rock of surge-shaft in proposed Hydropower Station contains mainly quartz mica schist, After exploration and laboratory tests, It found that the rock belongs to soft rock ,which has obvious schistosity structure and typical transverse isotropic rheological characteristics. The rheological behavior of surrounding rock during construction and operation may significantly affect the stability of rock mass and the characteristics of lining structure due to the high level of regional crustal stress. In this paper, Through comprehensively reflecting regional geological structure, structure of the surge shaft and stress fields, A three dimensional numerical calculation model is established with considering the construction sequence and supporting lining measures, according to Viscoelastic plastic damage constitutive model of transversely isotropic rock mass based on laboratory test and field monitoring data, Study on the stability of surrounding rock and lining structure safety of the surge-shaft group during construction and operation by using FLAC3D. The results show: Under the influence of rheological effect of the surrounding rock in the process of construction excavation, Deformation of the surrounding rock increases with time, The effect of anchor support on the deformation of surrounding rock is obvious. After 500d excavation, the displacement of surrounding rock tends to converge; the surrounding rock is in a state of compression after excavation, The two times lining is conducive to the distribution of the stress field of surrounding rock. The value of the growth rate of surge shaft lining deformation gradually decreased with time during operation, The deformation of the 2 year is about 54% of the deformation of the long term (50 years). The stress level of surge shaft lining structure and surrounding rock tends to be stable after 1 years of operation. During operating period, The variation range of stress level of surrounding rock of surge-shaft is very small.