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利用岩石剪切流变仪,对龙滩水电站大型地下洞室群围岩中的无充填节理岩石进行了剪切流变试验,得到了节理岩石长期抗剪强度参数,与快速剪切试验获得的短期抗剪强度参数进行比较,发现长期抗剪强度参数有所降低,且粘聚力对时间敏感性高于内摩擦角。基于得到的剪切流变试验曲线,采用五元件粘弹性剪切流变模型对表现为粘弹性流变特性的试验曲线进行了辨识,获得了节理岩石的粘弹性剪切流变参数。然后将提出的非线性粘塑性体与五元件粘弹性剪切流变模型串联起来,建立了岩石七元件非线性粘弹塑性剪切流变模型。采用节理岩石加速剪切流变全程曲线,对七元件非线性粘弹塑性剪切流变模型进行了辨识,得到了非线性剪切流变模型材料参数,剪切流变模型与试验结果的比较,显示出了所建剪切流变模型的正确性与合理性。
Shear rheological tests were carried out on the unfilled jointed rock in the large underground caverns of Longtan Hydropower Station using the rock shear rheometer, and the long-term shear strength parameters of the jointed rock were obtained, which were compared with those obtained by the rapid shear test Short-term shear strength parameters were compared and found that long-term shear strength parameters have decreased, and the cohesion of the time sensitivity is higher than the internal friction angle. Based on the obtained shear rheological test curves, a five-element viscoelastic shear rheological model was used to identify the experimental curves showing the viscoelastic rheological properties. The viscoelastic shear rheological parameters of the jointed rock were obtained. Then the proposed nonlinear visco-plastic body is connected in series with the five-element viscoelastic shear rheological model to establish a nonlinear viscoelastic-plastic shear rheological model of seven-element rock. The non-linear viscoelasto-plastic shear rheological model of seven elements was identified by using the whole curve of accelerated shear flow of jointed rock, and the material parameters of the nonlinear shear rheological model were obtained. The comparison between the shear rheological model and the experimental results , Shows the correctness and rationality of the shear rheological model built.