基于模量软化法饱和粉砂永久剪切变形计算研究

STUDY OF PERMANENT SHEAR DEFORMATION OF SATURATEDCOMPACTED SILTY SAND BASED ON MODULUS SOFTENING METHOD

基于传统的模量软化法和双曲线弹性本构模型建立永久变形随时间变化的表达式。通过与动三轴试验结果对比发现,此类方法在应用于循环荷载下易液化的粉砂的永久变形计算时,具有明显的局限性。因此,结合粉砂容易液化而产生流变的特性,在力的平衡方程中引入流变项。通过分析力的平衡方程,发现引入流变项后能够更好地描述土体破坏前后的永久变形发展规律。同时,得出了方程中相关参数的计算方法,并将数值计算结果与试验结果进行比较,发现两者吻合度较高。研究为循环荷载作用下粉砂的永久剪切变形计算提供了一种新思路。

Based on the viewpoint of traditional modulus softening method and hyperbolic constitutive model,a formula of permanent deformation changing with time was established. Compared with results of dynamic triaxial test,it was found that the formula was impossibly used for the silty sand which was easily liquefied. On this basis,a rheological term was introduced into the stress equilibrium equation,by which the character of silty sand permanent deformation could be described properly. At the meantime,the way of calculating related parameters in the equations was also introduced. Plugging these parameters into the equilibrium equation,it showed that the numerical calculating results were highly identical with the test results. Although some problems needing for further studies,a new idea in studying the permanent strain was provided.