残坡积土动力特性的试验研究

Experimental Study on the Dynamic Properties of the Residual Soil

利用动单剪仪研究某地震滑坡地区残坡积土的动力强度特性,针对残坡积土进行了不同固结压力、不同干密度、不同振动频率下的动单剪试验。结果表明:在振动荷载作用下,饱和和非饱和残坡积土动剪应力-动剪应变关系呈双曲线型,动荷载频率越大、震动持续时间越长、产生的动应变越大;动剪切模量随动剪应变的增加而减小,阻尼比随着动剪应变的增加而增大;固结围压、干密度和振动频率对残坡积土的最大动剪切模量有显著影响;非饱和残坡积土的动剪模量和最大动剪模量较饱和土大,阻尼比较饱和土小。试验结果为该地震滑坡地区稳定性评价提供了相关参数,为动力作用下残坡积土变形机制和动本构模型的分析提供了必要的理论基础。

By using dynamic simple shear tests apparatus,the dynamic properties of the residual soil in an earthquake landslide area are analyzed though a series of dynamic simple shear tests for the different consolidation pressure,the different dry density,and the different vibration frequency dynamic.Experimental results show that under the vibration load the relationship of the dynamic shear stress and the dynamic shear strain is hyperbolic curve instead of linear.When the specimen subjected the same dynamic stress,the larger dynamic deformation is corresponding with higher frequency and the longer duration of shaking.Dynamic shear modulus decreases with the increase of dynamic shear strain and damping ratio increases with the increase of dynamic shear strain.Consolidation confining pressure,dry density and vibration frequency has significant influence on maximum dynamic shear modulus of the residual soil.the dynamic shear modulus and the maximum dynamic shear modulus of unsaturated residual soil is higher than saturated residual soil,while the damping ratio is smaller.This result could provide relevant parameters for stability evaluation in earthquake landslide area,and offer the necessary basis for the analysis of the loading deformation mechanism and the dynamic constitutive model of the residual under the dynamic pressure.