循环荷载下湖相软土动力特性研究  

STUDY OF DYNAMIC CHARACTERISTICS OF LACUSTRINE SOFT SOIL UNDER CYCLIC LOADING

作　　者：曾向军[1] 邓宗伟[1] 高乾丰[2] 朱志祥[3] 聂如松[3] 

机构地区：[1]湖南城市学院土木工程学院,湖南益阳413000 [2]湘潭大学土木工程与力学学院,湖南湘潭411105 [3]中南大学土木工程学院,长沙410075

出　　处：《工业建筑》2015年第3期109-114,108,共7页Industrial Construction

基　　金：国家自然科学基金资助项目(51308198);湖南省科技计划项目(2013GK3086);湖南省教育厅一般项目(13C119)

摘　　要：以洞庭湖区沉积软土为对象进行循环振动三轴试验,研究不同动应力幅值、振动频率和围压下湖相软土的动力特性。结果表明:湖相软土轴向累积应变多呈稳定型增长,动应力幅值越大,累积应变越大,振动频率或围压越大,累积应变越小;动孔隙水压力随动应力幅值的增大而增大,受振动频率的影响较小,同时随围压的变化规律不统一,有待进一步研究;动应力幅值或振动频率越大,动弹性模量越小,围压越大,动弹性模量越大,且动弹性模量随振动次数的增加存在衰减现象,衰减规律亦受动应力幅值、振动频率和围压的影响。道路运营初期是软基沉降控制的关键阶段,为减小软基沉降,应特别重视对浅层软土的处理,并严格控制车载质量和车速。Selecting the sedimentary soft soil in Dongting Lake district for dynamic triaxial test, the dynamic characteristics of soft soil under different stress amplitude, vibration frequency and different confining pressure were studied.The test results showed that the axial accumulated strain of lacustrine soft soil was mostly stable growth, and increased with the increase of stress amplitude, decreased with the increase of vibration frequency or confining pressure.The higher the cyclic stress amplitude, the greater the dynamic pore water pressure.The vibration frequency had less influence on dynamic pore water pressure, and the variation of dynamic pore water pressure affected by confining pressure was not uniform, needing further study.Dynamic elastic modulus decreased with the stress amplitude and vibration frequency increasing, and increased with the confining pressure increasing.Dynamic elastic modulus decayed with loading cycles, and the attenuation law was also subjected to the stress amplitude and vibration frequency and the confining pressure.The early operation period is the critical stage for settlement control of soft subgrade.In order to reduce the settlement, particular attention should be paid to the treatment of shallow soft soil;overweight and overspeed should not be allowed.

关 键 词：循环荷载 湖相软土 动力特性 动三轴试验 路基沉降 

分 类 号：TU447[建筑科学—岩土工程] TU435[建筑科学—土工工程]