石英云母片岩各向异性蠕变特性试验研究

为探明丹巴水电站地下厂房区石英云母片岩的各向异性流变力学特性,分别对片理方向不同的2组石英云母片岩试样进行了单轴压缩蠕变试验.根据石英云母片岩蠕变曲线的特征,通过串联一个非线性黏性元件,对损伤西原模型进行改进,并按照Lemaitre应变等效原理推导了模型的蠕变方程,获得了石英云母片岩的一维流变模型参数;分析了片理面和应力水平对瞬时蠕变、衰减蠕变、稳定蠕变和加速蠕变等特性的影响.结果表明:随应力水平提高,石英云母片岩的瞬时弹性模量基本不变,而滞后弹性模量、稳定黏性系数和蠕变破坏时间均减小;加载方向与片理面垂直时,石英云母片岩具有较强的黏塑性和较高强度;加载方向与片理面平行时,石英云母片岩具有较强的瞬时弹性、黏弹性、黏性和延性. 

Experimental Investigation on Anisotropic Creep Characteristics of Quartz Mica Schist

To investigate the anisotropic rheological properties of quartz mica schist in the underground chamber of Danba hydropower station, two groups of uniaxial compression creep tests were conducted on quartz mica schist samples. Based on the creep characteristics of quartz mica schist, the damage Nishihara model was improved by adding a nonlinear viscous component in series, the creep equation was derived in the light of the Lemaitre strain equivalence principle, and one-dimensional rheological mechanical parameters were obtained. Furthermore, the effects of schistosity and stress level on transient creep, decelerating creep, steady-state creep, accelerating creep and other creep characteristics were analyzed. The research results show that with the increase of stress, the instantaneous elastic modulus of quartz mica schist remains a constant roughly, but its hysteretic elastic modulus, stable viscous coefficient and creep failure time decrease. Quartz mica schist exhibits a strong visco-plasticity and high strength when loading direction is perpendicular to schistosity, while quartz mica schist shows strong instantaneous elasticity, visco-elasticity, viscosity and ductility when the loading direction is parallel to schistosity.