低频循环荷载下饱和软土的孔压及变形特性的试验研究

Laboratory Studies on the Deformation and Pore Water Characteristics of Soft Cohesive Soils under Low Frequency Traffic Loads

分析了振动频率对饱和软土动孔压变化和累积塑性变形的研究现状,利用美国GCTS开发制造的SPAX-2000动静真三轴测试系统,研究了交通荷载下低频对饱和淤泥质软黏土的孔压以及塑性变形的影响规律。试验结果表明,频率越低,总动孔压值和累积塑性应变越大。当频率低于0.1 Hz时,加载频率对动孔压和塑性应变的增长速率影响较大,若频率大于0.5Hz时,频率的影响可以忽略不计。在高循环应力作用下,高次数的循环荷载能对动孔压和累积塑性应变产生较大影响;若在低循环应力水平下,循环次数的影响可以忽略。

The state-of-the art of the effect of cyclic loading frequency on the change of the dynamic pore water pressure as well as the cumulative plastic strain is reviewed and studied in this paper.The true static and cyclic triaxial test equipment SPAX-200 made by GCTS was used to study the performance of the saturated peaty soft clay.The effect of traffic loading on the pore water pressure and the cumulative plastic strain in the sample was investigated.The test results indicate that,the lower the cyclic load frequency,the larger the total dynamic pore pressure value and the cumulative plastic strain in the soil sample.When the loading frequency is lower than 0.1 Hz,larger influence of loading frequency on the rate of the pore pressure and plastic strain increase.When the loading frequency is greater than 0.5Hz,the loading frequency has negligible influence.Under the high cyclic stress level,the number of cyclic loading has a large impact on the dynamic pore water pressure and the cumulative plastic strain.However,the influence of the cyclic loading number is minimal when the cyclic stress level is low.