| 荆江大堤下伏饱和粉细砂动力特性试验研究 |
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| 引用本文： | 江洎洧,饶锡保,张伟,潘家军,王占彬.荆江大堤下伏饱和粉细砂动力特性试验研究[J].西北地震学报,2015,37(3):759-764. |
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| 作者姓名： | 江洎洧 饶锡保 张伟 潘家军 王占彬 |
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| 作者单位： | 长江科学院水利部岩土力学与工程重点实验室, 湖北武汉 430010;长江科学院水利部岩土力学与工程重点实验室, 湖北武汉 430010;长江科学院水利部岩土力学与工程重点实验室, 湖北武汉 430010;长江科学院水利部岩土力学与工程重点实验室, 湖北武汉 430010;长江科学院水利部岩土力学与工程重点实验室, 湖北武汉 430010 |
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| 基金项目： | 国家自然科学基金项目(51309029,51109013);中央级公益性科研院所基本科研业务费(20140620164601) |
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| 摘 要： | 针对荆江大堤江陵段下伏地层广泛分布的饱和粉细砂,参照原位试验成果重塑粉细砂试样,按估算的固结应力比(Kc约为1.6)对试样动剪模量、阻尼比及总应力动强度进行测试,结果表明:(1)试样应力-应变骨干曲线与Hardin-Drnevich双曲线模型假设高度吻合,Hardin公式可很好地拟合动模量/阻尼比与动应变的关系。在研究试样密实度范围内,最大动模量随围压和密实度的增加而增加,但围压对动模量的敏感性更高,且相同围压下动剪模量比与动应变关系曲线近乎重合。围压增大或密实度升高均会引起阻尼比的降低,1%应变对应的阻尼比分布在0.15~0.21之间;(2)偏压状态下以累积轴向应变5%作为液化判别标准进行抗液化强度试验,随特征振次及测试围压的增大,液化动剪应力比相应减小,试样振动孔压比最高仅能达到0.8~0.9;(3)由总应力法求取的动内摩擦角与黏聚力均随设定特征振次的增加而下降,且内聚力并非约等于0,表明动力作用下该试样具有一定的黏滞性。
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| 关 键 词： | 荆江大堤 饱和粉细砂 动模量及阻尼比 液化动强度 |
| 收稿时间： | 2014/8/20 0:00:00 |
Experimental Study on Dynamic Properties of Saturated Fine Sand in Jingjiang Levees |
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| JIANG Ji-wei,RAO Xi-bao,ZHANG Wei,PAN Jia-jun and WANG Zhan-bin.Experimental Study on Dynamic Properties of Saturated Fine Sand in Jingjiang Levees[J].Northwestern Seismological Journal,2015,37(3):759-764. |
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| Authors: | JIANG Ji-wei RAO Xi-bao ZHANG Wei PAN Jia-jun and WANG Zhan-bin |
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| Institution: | Key Laboratory of Geotechnical Mechanics and Engineering of Ministry of Water Resources, Yangtze RiverScientific Research Institute, Wuhan 430010, Hubei, China;Key Laboratory of Geotechnical Mechanics and Engineering of Ministry of Water Resources, Yangtze RiverScientific Research Institute, Wuhan 430010, Hubei, China;Key Laboratory of Geotechnical Mechanics and Engineering of Ministry of Water Resources, Yangtze RiverScientific Research Institute, Wuhan 430010, Hubei, China;Key Laboratory of Geotechnical Mechanics and Engineering of Ministry of Water Resources, Yangtze RiverScientific Research Institute, Wuhan 430010, Hubei, China;Key Laboratory of Geotechnical Mechanics and Engineering of Ministry of Water Resources, Yangtze RiverScientific Research Institute, Wuhan 430010, Hubei, China |
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| Abstract: | Saturated fine sand is widespread under the Jiangling section of the Jingjiang levees, so a system test of the levees'' dynamical properties is necessary. Using specimens built with reference to in situ test results with an estimated consolidation stress ratio Kc (approximately 1.6), we conducted a series of dynamical triaxial tests to study the dynamical elastic modulus, damping ratio, and dynamical strength. The results are as follows:(1) The relationship curves of the dynamic stress-strain of the specimens and the Hardin-Drnevich hyperbolic model assumption match well, and Hardin''s formula is also a good fit with the relationship between the dynamic modulus/damping ratio and dynamic strain. In the actual compactness range of the specimens, the maximum dynamic modulus increases with increase in the confining pressure and compactness, and the confining condition is more sensitive. Furthermore, with the same confining pressure but different compactness, the fitting curves of the shear modulus ratio and the dynamic strain nearly coincide. In addition, the damping ratio decreases with increase in the confining pressure and compactness, and when the dynamic strain is 1%, the corresponding damping ratio for specimens with different conditions ranges from 0.15 to 0.21. (2) Under bias-consolidation conditions, we set a cumulative axial strain of 5% as the liquefaction standard. With increases in the confining pressure and number of dynamic cycles, the dynamic shear stress ratio decreases, and the maximum dynamic pore pressure ratio can only reach 0.8~0.9. (3) The dynamic friction and cohesion obtained by the total stress method decrease with increases in the number of dynamic cycles. In addition, the cohesion of the specimens is not approximately equal to 0, which indicates a viscosity characteristic of saturated find sand under dynamic action. |
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| Keywords: | Jingjiang levees saturated fine sand dynamic modulus and damping ratio liquefied dynamic strength |
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