循环剪切作用下泥质软岩本构模型研究

库区微震频发现象使泥质软岩受循环剪切动力作用。基于分数阶西原模型,将Able黏壶进行改进,获得相应条件下的本构模型,并通过泥质软岩试样循环剪切试验对该本构模型进行了验证。研究表明:①原有分数阶西原本构模型可归纳为本模型正弦函数(循环作用)为零时的特殊解;②模型表现出较好的适用性(R²∈(0.96,0.98)),且方程曲线具备试验曲线的“单双拐点”特征;③模型主要影响因素为分数阶阶数n,其中稳定型方程n∈(0,0.6)、破坏型方程n∈(0.6,1.0);④随n的增加,抗剪模量G与黏滞系数η大致呈现降低趋势,可较好反映宏观现象;⑤从参数扰动的角度解释了以往文献出现的η随n增加可能表现出的无规律波动现象。研究成果可为微震条件下含泥质软岩边坡长期稳定性控制提供理论参考。

Study on Constitutive Model of Muddy Soft Rock under Cyclic Shear

The frequent occurrence of microseisms in the reservoir area makes the muddy soft rock subject to cyclic shear dynamic action. Based on the fractional Nishihara model (FNM), the adhesive pot of Able is improved, and the constitutive model under the corresponding conditions is further obtained, which is verified by the cyclic shear test of the muddy soft rock sample. The research shows that: (1) the original FNM can be summed up as a special solution when the sinusoidal function (cyclic action) is zero in the proposed mode. (2) The model shows good applicability (R²∈(0.96,0.98)), and the equation curve has the characteristics of “single and double turning points”, which can be found in the test. (3) The main influencing factor of the model is fractional order n, in which the stability condition n∈(0,0.6), the failure condition n∈(0.6,1.0). (4) With the increase of n, the shear modulus G and viscosity coefficient η decrease, which can better reflect the macroscopic phenomenon. (5) From the point of view of parameter disturbance, the irregular fluctuation of η with the increase of n in the previous literature is explained. The research results can provide theoretical reference for the long-term stability control of muddy soft rock slope under microseismic condition.