辽河三角洲相沉积软土动力特性试验

针对辽河三角洲相沉积软土，在固定振动频率f=1.0 Hz，固结压力为100、200和300 kPa 3种情况下进行循环荷载的动三轴试验，分析了不同固结压力下动应变ε_d、动强度σ_d与荷载循环次数和动剪应变r_d之间的关系。结果表明:在固定振动频率和同一个固结比K的条件下，动强度σ_d与载荷循环次数在单对数坐标系中具有良好的线性相关性。动剪切模量G_d随动剪应变r_d的增大而增大，阻尼比D随动剪应变r_d的增大而减小，G_d-r_d、D-r_d曲线在直角坐标中具有分段性，以应变量在4.0%～5.4%之间出现拐点居多。与其它不同特性的软土相比较，辽河三角洲相沉积软土具有以下特征：(1)动强度指标明显低于其它类软土，(2)阻尼比与剪应变的关系与其它类软土有2个拐点不同，该类软土仅在r_d =2×10^-3处存在一个拐点。

Dynamic Properties Test of Soft Soil of Liaohe Delta Deposit

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.