基于非饱和渗流特征的土体抗剪强度衰减预测研究

Prediction of soil shear strength attenuation based on unsaturated seepage characteristics

当前工程建设普遍面临非饱和土环境,而非饱和土抗剪强度的预测一直是一个难点和热点问题,为此,本文提出了一种基于非饱和渗流特征的土体抗剪强度衰减预测方法。利用水体质量守恒方程,建立非饱和渗流控制方程,通过定义第三类边界条件,构建非饱和渗流数学模型。基于此,采用空间域离散和时间域差分原理,获取有限元计算模式,并结合Chebyshev网格法,计算有限元网格间的离散格式,通过数值模拟获取土体的土-水特征曲线,建立其与土体抗剪强度关系,获得土体抗剪强度衰减预测公式。实验结果表明:所提方法预测结果均方根误差仅为1.26%,且抗剪强度预测结果与实际结果具有较强的一致性。以上实验结果表明所提方法能够准确地预测土体抗剪强度衰减情况,具有理想的应用效果。

At present,engineering construction is generally faced with unsaturated soil environment,and the prediction of shear strength of unsaturated soil is always a difficult and hot problem.Therefore,a method for predicting shear strength attenuation based on unsaturated seepage characteristics is proposed in this paper.Based on the water mass conservation equation,the control equation of unsaturated seepage flow is established,and the mathematical model of unsaturated seepage flow is constructed by defining the third kind of boundary conditions.Based on this,the finite element calculation model is obtained by using the spatial domain discrete and time-domain difference principles,and the discrete format between the finite element grids is calculated by combining the Chebyshev mesh method.The soil-water characteristic curve of soil is obtained by numerical simulation,and the relationship between it and the shear strength of soil is established,and the prediction formula for the shear strength decay of soil is obtained.The experimental results show that the root-mean-square error of the proposed method is only 1.26%,and the predicted results of shear strength are in good agreement with the actual results.The above experimental results show that the proposed method can accurately predict the attenuation of soil shear strength and has ideal application effect.