振动频率对饱和砂土液化强度的影响  

The Influences of the Vibration Frequencies on Liquefaction Strength of Saturated Sands

作　　者：郭莹[1] 贺林[1] 

机构地区：[1]大连理工大学海岸和近海工程国家重点实验室大连理工大学土木水利学院,辽宁大连116024

出　　处：《防灾减灾工程学报》2009年第6期618-623,共6页Journal of Disaster Prevention and Mitigation Engineering

基　　金：国家自然科学基金重点项目(50639010);国家自然科学青年基金项目(50808033)资助

摘　　要：采用"土工静力-动力液压三轴-扭转多功能剪切仪"对饱和砂土进行了一系列动三轴实验,探讨了振动频率对液化强度数值的影响程度。在1.0、1.5固结比和0.05、0.10、1.00 Hz振动频率条件下,针对相对密实度分别为70%、28%的密砂和松砂进行了100、200、300 kPa围压和100 kPa围压条件下的液化强度实验。实验结果表明,饱和密砂和松砂在各种固结条件下,液化强度随着振动频率的增大而增大,相同破坏振次时,各种实验条件下的液化强度与振动频率的关系在双对数坐标上均符合线性关系;振动频率由0.05 Hz变化到1.00 Hz时,液化强度相差达25%以上;动强度指标φd值随振动频率的增大而增大,最大相差12.2%;随着振动频率的增大,砂土达到液化破坏所需的时间明显缩短;振动频率对松砂液化强度的影响比对密砂的影响更为显著。A series of cyclic tri-axial shear tests were carried out on saturated sand by the soil static and dynamic hydraulic pressure triaxial and torsion multifunction shear apparatus. The influence degree of the vibration frequency on liquefaction strength value is studied. In the conditions of consolidation ratio at 1.0 and 1.5 and the vibration frequencies at 0.05, 0.1 and 1.0 Hz, the liquefaction intension experiments were conducted on the dense sand of 70% relative density under 100, 200, 300 kPa confining pressures and the 28% loose sand under 100 kPa confining pressure. The experimental results show that the liquefaction strengths of the saturated dense and loose sand were increased with the increasing of vibration frequencies under different consolidation conditions. With the same destruction vibration frequency, all of the relations between the liquefaction strength and vibration frequency on log-log coordinates were linear. The change of liquefaction strength from 0.05 Hz to 1 Hz caused liquefaction strength changing over 25 %. The dynamic strength index % was increased with the increasing of vibration frequencies, the maximum difference was 12.2%. The time of the sand destruction became shorter with the increasing of vibration frequencies. The influences of the vibration frequencies on loose sand were more obviously than dense sand.

关 键 词：动三轴实验 饱和砂土 振动频率 液化强度 动强度指标 

分 类 号：TU441.5[建筑科学—岩土工程]