以天津滨海新区结构性海积软土为研究对象,采用GCTS动静扭剪试验仪,基于正弦波与方波两种波形,在固结排水条件下施加不同初始静偏应力,通过考虑循环振次、应力幅值、振动频率以及围压等因素对土体结构的影响,研究结构性软黏土的动力特性。试验结果表明:初始静偏应力小于土体初始屈服应力时,施加静偏应力增加了土体固结度,提高了其结构强度,应变软化现象减弱,累积塑性应变曲线中屈服点对应的应力值大。初始静偏应力大于土体初始屈服应力时,土体初始结构破坏,出现严重的应变软化现象,累积塑性应变曲线迅速由稳定型转变为临界型,且在同条件下,方波应变值始终大于正弦波。孔压变化与初始静偏应力有关,随着静偏应力增大其孔压滞后现象严重。土体屈服应变随初始静偏应力增大而增加,静偏应力及振次相同时,方波作用下的土体屈服应变值小于正弦波。两种波形下,土体屈服应变随振次增加均呈减小趋势,且最终均会趋于一点,正弦波趋于相同数值下的振次远大于方波。土体动强度随应变标准提高而呈现增大趋势,应变标准为屈服应变值时,动强度曲线表现为先陡后缓,其他应变标准下动强度曲线较为平缓。两种波形下的动强度随振次增加而减小,最终均会趋于一点,且正弦波值大于方波。 Taking the structural marine soft soil in Tianjin Binhai New Area as the research object, GCTS static and torsional shear tester was used. Based on the two waveforms of sine wave and square wave, different initial static deviatoric stresses were applied under the condition of consolidation drainage. By considering cyclic vibration times , The influence of stress amplitude, vibration frequency and confining pressure on the soil structure, and the dynamic characteristics of the structural soft clay are studied. The experimental results show that when the initial static deviatoric stress is less than the initial yield stress of soil, the application of static deviatoric stress increases the degree of soil consolidation, increases its structural strength and weakens the strain softening phenomenon. The stress corresponding to the yield point in the cumulative plastic strain curve Big. When the initial static deviatoric stress is larger than the initial yield stress of soil, the initial structure of the soil is damaged and serious strain softening occurs. The cumulative plastic strain curve rapidly changes from stable to critical. Under the same conditions, the square wave strain is always greater than Sine wave. The pore pressure change is related to the initial static deviatoric stress, and the pore pressure hysteresis is serious with the increase of static deviatoric stress. Soil yield strain increases with initial static deviatoric stress. When the static deviatoric stress and vibration times are the same, the soil yield strain under the action of square wave is smaller than that of sine wave. Under both waveforms, the yield strain of soil decreases with the increase of vibration frequency, and eventually tends to a little. The sine wave tends to vibrate much less than the square wave under the same value. The dynamic strength of soil increases with the increase of strain standard. When the strain standard is yield strain value, the dynamic strength curve shows steep and slow afterwards, and the lower strain curve of other strain standards is gentle. The dynamic strength of the two waveforms decreases with the increase of the vibration frequency, eventually tends to be a little bit, and the sine wave is larger than the square wave.