应变控制下舟山岱山海相软土动弹性模量及阻尼比试验研究

发布时间：2018-04-04 10:54

本文选题：土力学　切入点：海相软土　出处：《岩石力学与工程学报》2014年07期

【摘要】：为探究舟山岱山海域海底岩土地质层动力学特性,借助GDS动三轴系统对应变控制循环荷载作用下舟山原状海相软土动弹性模量和阻尼比变化规律进行研究。得到舟山岱山海相软土动应力、动应变、动孔压时程曲线以及应力应变关系曲线,讨论各围压下动弹性模量和阻尼比随动应变幅值的变化趋势。结果表明:舟山岱山海相软土的应力应变关系曲线为不完全封闭的滞回圈;循环加载过程中土样发生应变软化;同级加载下动弹性模量和阻尼比数据点围绕某恒值作小幅波动,故可采用代表该恒值的均值来表征该级加载下的动弹性模量和阻尼比,由此所得的各围压下动弹性模量动应变幅值、阻尼比动应变幅值关系曲线呈收敛趋势;由修正Hardin-Drnevich(H-D)模型建立的应变控制下舟山岱山海相软土动弹模及阻尼比归一化模型可揭示深海环境中海相土受围压影响的动力学机制。将共振柱试验结果与动三轴研究作比较,得到结论:两类试验成果可以互为补充,前者可揭示海相土的弹性特征,后者可反映海相土弹塑性阶段的动力学特性;舟山岱山海相软土在两类试验中均对围压敏感。
[Abstract]:In order to investigate the dynamic characteristics of undersea rock and soil strata in Daishan sea area of Zhoushan, the dynamic elastic modulus and damping ratio of undisturbed marine soft soil in Zhoushan are studied by means of GDS dynamic triaxial system under strain-controlled cyclic loading.The dynamic stress, dynamic strain, dynamic pore pressure time-history curve and stress-strain relation curve of the marine soft soil in Daishan, Zhoushan are obtained. The dynamic elastic modulus and damping ratio under each confining pressure are discussed.The results show that the stress-strain relationship curve of the marine soft soil in Daishan of Zhoushan is an incomplete closed hysteretic loop, and the strain softening occurs during cyclic loading.The data points of dynamic elastic modulus and damping ratio under the same stage load fluctuate slightly around a constant value, so the mean value representing the constant value can be used to characterize the dynamic elastic modulus and damping ratio under the same stage loading.The dynamic elastic modulus and the dynamic strain amplitude under the confining pressure obtained from this method have a convergent trend in relation to the damping ratio and the dynamic strain amplitude.The model of dynamic elastic model and damping ratio of Daishan marine soft soil under strain control established by modified Hardin-Drnevichn H-D) model can reveal the dynamic mechanism of marine soil affected by confining pressure in deep-sea environment.By comparing the results of the resonance column test with the dynamic triaxial study, it is concluded that the two kinds of test results can complement each other, the former can reveal the elastic characteristics of the marine soil, and the latter can reflect the dynamic characteristics of the elastic-plastic stage of the marine soil.The marine soft soil of Daishan in Zhoushan is sensitive to confining pressure in both kinds of tests.
【作者单位】：中国水电顾问集团华东勘测设计研究院;浙江海洋学院;
【基金】：国家自然科学基金资助项目(51109118) 中国博士后科学基金项目(20100470344) 浙江海洋学院中青年教师资助项目(11042101512)
【分类号】：TU435

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