Abstract:

To study the delta deposit soft soil’s dynamic characteristics of Liaohe, procedures of the dynamic triaxial tests under the consolidation pressure of 100 kPa，200 kPa，300 kPa with the fixed seismic frequency of 0.1 Hz is carried out. Relationship between the dynamic strain ε_d, the dynamic intensity σ_d, the load cycle-index and the dynamic shear strain rd under the different consolidation pressure is analyzed. The results of tests show that under the conditions of fixed seismic frequency and  identical consolidation ratio K, the dynamic intensity σ_d and load cycleindex have favorable linearity in the odd logarithm coordinate system. The dynamic shear modulus G_d increases  with the dynamic shear strain r_d increment,and the damping ratio D diminishes with the dynamic shear strain r_d increment. The correlations of  G_d and  r_d, D and r_d have characteristics of segmentation in the rectangular coordinates, and the value of strain presents more inflexions between 4.0% and 5.4%. Dynamic strain indexing of soft soil is significantly lower than other types of soft soil. And the relations of damping ratio and the shearing strain is different from other types of soft soils, which have two inflection points，this kind of soft soil only existes one inflection point in r_d=2×10^-3.

Key words: delta deposit soft soil, dynamic strain, dynamic intensity, load, cycle-index, dynamic characteristic