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为研究饱和密砂土地基高频振动沉桩过程中土体动力特性,采用高频振动三轴仪对饱和密砂土进行不同振动频率下的振动液化试验,根据试验结果,给出液化时间t、液化振次NL、振动频率f三者的关系式。研究频率改变对动孔隙水压力随时间振次增长的影响,并将试验得出的孔压比和振次比关系与已有的动孔压应力模型比较,发现频率的提高会改变曲线形态。频率对饱和密砂振动过程中轴向应变的发展有显著影响,频率提高会降低砂土液化时的轴向应变,不同的振动频率会改变砂土液化前轴向应变随时间和振次的增长速度,影响轴向应变比与振次比关系。
In order to study the dynamic characteristics of soils in the process of high-frequency vibration pile-sinking on saturated sand foundation, the vibrational liquefaction test of saturated sand at different vibration frequencies was carried out by using high-frequency vibration triaxial apparatus. According to the test results, the liquefaction time t , Liquefaction vibration NL, vibration frequency f the relationship between the three. The effect of frequency change on dynamic pore water pressure increase with time was studied. The relationship between pore pressure ratio and vibration frequency ratio was compared with the existing dynamic stress model. It is found that the increase of frequency will change the curve shape. The frequency has significant influence on the development of axial strain in the sandstone saturated with sand. The increase of frequency will reduce the axial strain of sand when liquefaction. The different vibration frequency will change the axial strain before sand liquefaction with the increase of time and vibration Speed, axial strain ratio and vibration ratio relationship.