桩基系统在地基液化和土体流动过程中的三维响应

3-dimensional Response of a Pile-ground System During Liquefaction and Flow Process of the Ground

摘要:

松散的饱和砂土在液化之前可作为固体看待,但当过量的孔隙水压达到初始侧应力时它成为液体,之后又恢复其强度.这个过程不能各自单独处理,而应视为一个从固态到液态,或从液态到固态的连续变化过程.因此,整个伴随着地基液化--土体流动现象全过程应作为一个在固态和液态之间相变的系列过程.本文导出了一个简单的基本方程式,可以表达松散饱和砂土在液化和地基侧向滑移现象期间的固-液相转换.该基本方程式可用作桩基系统的动力分析,其适用性通过与弹塑性基本方程的比较得到验证.

Abstract:

Loose saturated sand behaves as a solid before liquefaction but as a fluid when the excess pore water pressure reaches the initial confining stress, after which it recovers its strength. Those processes cannot be treated independently,but should be considered continuous processes that represent change from the solid to fluid state or from the fluid to solid state. Therefore, the total processes of the combined liquefaction-ground flow phenomenon should be treated as a series of processes of phase transformation between the solid and fluid states. In this paper, a simple constitutive equation for loose saturated sand was developed to be able to express the phase transformation between a solid and fluid during liquefaction and the ground flow phenomenon. This constitutive equation was used for a dynamic analysis of a pile-ground system,and its applicability investigated by comparing with the elasto-plastic constitutive equation.