不同循环荷载频率下软黏土动力特性试验研究  

Experimental study on dynamic properties of soft clay under different cyclic loading frequencies

作　　者：周盈 孙苗苗 夏凡 夏唐代[1] 何绍衡 李雨杰 ZHOU Ying;SUN Miaomiao;XIA Fan;XIA Tangdai;HE Shaoheng;LI Yujie(Department of Architecture and Civil Engineering,Zhejiang University,Hangzhou 310058,Zhejiang,China;Department of Civil Engineering,Hangzhou City University,Hangzhou 310015,Zhejiang,China;Department of Civil and Environmental Engineering,The Hong Kong Polytechnic University,Hong Kong 999077,China;Hainan Institute of Zhejiang University,Sanya 572025,Hainan,China)

机构地区：[1]浙江大学建筑工程学院,浙江杭州310058 [2]浙大城市学院土木工程系,浙江杭州310015 [3]香港理工大学土木与环境工程系,中国香港999077 [4]浙江大学海南研究院,海南三亚572025

出　　处：《地基处理》2024年第4期337-346,共10页Journal of Ground Improvement

基　　金：浙江省自然科学基金资助项目(LTGG23E080002)。

摘　　要：通过开展饱和重塑软黏土GDS动三轴试验,研究了不同频率、循环荷载动应力比和初始有效应力作用下土体不排水累积轴向应变、累积孔压及回弹模量演化规律,并探明相关作用机理。研究结果表明:循环荷载动应力比、初始有效围压和频率对土体累积轴向应变、累积孔压及回弹模量影响较大。土体累积轴向应变、累积孔压与动应力比、初始有效应力呈正相关,与回弹模量则呈负相关。低循环应力比下,频率越高,软黏土产生的轴向累积应变与孔压越大,试样回弹模量越小;当动应力比过大时,软黏土试样则呈现相反的规律。根据上述规律,提出在不排水循环条件下,土颗粒吸收振动所产生的能量导致吸附于表面的强弱结合水发生转化,且在不同频率交通循环荷载下,软黏土变形受到了频率产生能量与黏土滞后效应的共同影响。研究结论可为交通工程中软土地基的变形计算提供重要参考。The GDS dynamic triaxial test was carried out on saturated remolded soft clay to study the evolution of undrained accumulated axial strain,accumulated pore water pressure and resilience modulus of soil under different frequencies,cyclic dynamic stress ratios and initial effective stresses,aiming to explore the relevant mechanisms.Results show that the accumulated axial strain,accumulated pore water pressure and resilience modulus of soil are significantly affected by the cyclic dynamic stress ratio,initial effective confining pressure,and frequency.The accumulated axial strain and accumulated pore water pressure of soil are positively correlated with the cyclic dynamic stress ratio and initial effective stress,while the resilience modulus is negatively correlated.Under low cyclic stress ratio,the higher the frequency,the greater the accumulated axial strain and pore water pressure of the soft clay,and the smaller the resilience modulus.When the dynamic stress ratio is too high,the soft clay sample exhibits the opposite pattern.Based on these observations,it is suggested that in undrained cyclic conditions,soil particles absorb energy generated by vibration,leading to the transformation of strongly and weakly bound water absorbed on the surface.Furthermore,the soft clay deformation is influenced by frequency-induced energy and clay hysteresis effect during cyclic traffic load of varying frequencies.These findings offer valuable insights for predicting deformation in soft soil foundations in traffic engineering applications.

关 键 词：循环交通荷载 软黏土 振动频率 回弹模量 结合水 滞后效应 

分 类 号：TU43[建筑科学—岩土工程]