中文摘要：

在黄河水下三角洲粉土层不同深度布设电传感器和孔压探头,实时记录循环荷载作用过程中粉土体的电性变化和孔压变化。基于土的电阻率对土体结构状态反映能力,分析振动响应过程土体变形特性,确定外部振动对土体的改造作用,揭示波浪作用下土体破坏机制。实验结果表明：振动荷载作用下,一定深度内的粉土体电阻率会发生不均匀改变,由此揭示土体的分层变化规律。分层变化主要发生在循环荷载作用的初始阶段,对应孔压上升期。而整个加荷和卸荷作用过程中,40～50 cm深度区间土体电阻率未发生明显变化的现象表明,外部振动作用过程中一定深度位置土体并未发生相应振动位移,保持相对稳定。相近位置的土体微结构分析和振动作用过程土体强度原位监测结果也验证了这种认识。土体的这种分层特征可能会引起波浪作用下粉土层共振现象发生,从而形成黄河水下三角洲底坡失稳的控制性因素。

英文摘要：

Electrodes and pore water pressure probes are laid at different depths of silty soil strata in Yellow River Delta.With themr,esistivity and pore water pressure are measured when the silty soil is vibrated vertically with the effects of outside force.Based on the analysis of key factors influencing the resistivity of saturated silty soil,it is revealed that the state of silty soil varies with time along depth when the silty soil is vibrated vertically and after the vibration stopped.Furthermore,the deformation characteristics of soil are analyzed to research the failure mechanism of soil mass under wave actions.Research results show that,under the vibration loading,the electrical resistivity of soil tends to show heterogenous changes at certain depth,and hence the stratified changing regularity of soil mass is discovered.The stratified changes mainly happen in the initial stage of vibration,corresponding to the rising stage of pore water pressure.But in the whole course of loading and unloading,the electrical resistivity of soil in the depth from 40 to 50 cm does not change prominently,which indicates that the soil at certain depth does not suffer corresponding vibration displacement,but keeps relatively stable.Laboratory analyses of soil microstructures and in-situ monitoring of soil intensity also prove these findings.The stratified characteristics may cause resonance vibration of the silty soil under wave actions,and consequently form the dominant factor of slope failures in the subaqueous Yellow River Delta.