一种考虑剪切速率的粗糙结构面剪切强度准则
New shear strength criterion for rough rock joints considering shear velocity
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摘要: 动荷载(不同剪切速率)下的节理岩体结构稳定性是目前工程建设亟待解决的问题之一。以黄岛国家石油储备库地下水封石油洞库工程为工程背景,采用JAW-600岩石剪切流变-渗流耦合试验机对4种粗糙度下的类岩石粗糙结构面进行不同剪切速率下的常规剪切试验,对结构面的强度特性进行了基础性研究。研究结果表明:剪切速率和粗糙度对结构面剪切强度都有较为明显的影响;同一结构面的剪切强度随着剪切速率的增大而减小,并不受粗糙度系数的影响;同时结构面剪切强度随粗糙度系数增加呈现出线性增加的趋势,但不受剪切速率的影响。最后,基于试验结果与Barton模型,提出考虑剪切速率的粗糙结构面剪切强度模型。Barton标准粗糙剖面线结构面及粗糙结构面的试验结果与新模型预测值误差保持在20%之内,平均误差为10.539%,能够较好的预测粗糙结构面动荷载条件下剪切强度。Abstract: The stability of jointed rock under dynamic loading conditions, which is under different shear velocities, is one of the urgent problems in the current engineering construction. By using JAW-600 coupled shear-flow machine,four groups of rock-like joints with different roughness coefficients are sheared with different shear velocities based on the rock joints from the underground caverns of Huangdao State Oil Reserves. The experimental results show that the shear velocity and joint roughness coefficient obviously affect the shear strength. The shear strength for any rough rock joints decreases with the increasing shear velocity. Meanwhile, the shear strength under any shear velocity shows a linear increase with the joint roughness coefficients. On the basis of the experimental data and Barton’s criterion for shear strength, a new shear strength criterion considering shear velocity for rough rock joints is proposed. Then its correctness is verified by the shear strength of rock joints proposed by Barton with an average estimation error of 10.539% .