下卧饱和半空间粘弹性土层上基础阻抗函数的分析

Dynamic impedance of foundations on viscoelastic stratum and saturated elastic half-space

由于地下水的影响,实际土层一般由含水土层和不含水土层组成。由于求解的复杂性,目前基础阻抗函数的求解中很少考虑这种地基情形。根据干土是饱和土的特殊情形这一事实,通过将液相压缩模量、孔隙比以及惯性耦合质量密度取为零,可以使干土的动力反应统一到饱和土动力反应求解方案中,从而可通过饱和地基上基础阻抗函数的一种求解方法,解决饱和土和干土并存时基础阻抗函数的求解问题。地基无限域的影响通过局部透射人工边界考虑。通过算例验证了该方法的可行性,并考察了干土层厚度以及基础埋深对动力阻抗的影响。

In general, the soil stratum consists of two-phase saturated poroelastic zones and single-phase viscoelastic zones duo to ground water. In most cases of dynamic impedance analysis, the soil has been assumed to be a viscoelastic or saturated medium. Little attention has been paid to the analysis of foundation on stratum consisting viscoelastic and saturated soil. Based on the fact that single-phase soil is a special case of two-phase saturated soil, the dynamic analysis of single-phase soil can be unified into the analysis of saturated soil by setting the bulk modulus of pore fluid, porosity and the coupling mass den- sity to be zero. Thus, the dynamic impedance of foundations on viscoelastic and saturated stratum can be analyzed by a method for saturated medium case. The technique is applied to the computation of the dynamic impedance of rectangular foun- dations on viscoelastic and saturated stratum. The effect of dry soil thickness and the embedded depth of foundation on the dynamic impedance are examined.