| 饱和剪胀性砂土液化后流滑现象与机理 |
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| 引用本文： | 张建民,王富强.饱和剪胀性砂土液化后流滑现象与机理[J].岩土力学,2010,31(9):2711-2715. |
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| 作者姓名： | 张建民 王富强 |
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| 作者单位： | 1. 清华大学,岩土工程研究所,北京100084;清华大学,水沙科学与水利水电工程国家重点实验室,北京100084
2. 清华大学,岩土工程研究所,北京100084;中国水电工程顾问集团公司,北京100011 |
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| 基金项目： | 973项目课题，国家自然科学基金 |
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| 摘 要： | 基于完全不排水试验的已有研究结果表明,只有在饱和松砂中才可能发生流滑现象,较密实的饱和剪胀性砂土在初始液化后的不排水循环或单调剪切作用条件下,则会呈现出所谓往返活动性或抗剪强度恢复现象。然而,实际土工抗震边值问题中的饱和砂土在许多情况下并不能够被视为处于完全不排水条件,可能由于土性和变形等因素的不同而处于剪切排水甚至剪切吸水条件。通过对饱和砂土液化后常剪切吸水率试验结果的分析指出,剪切吸水条件可能导致剪胀性砂土的抗剪能力显著降低、甚至发生流滑现象。基于可逆性与不可逆性剪切体应变的概念以及3种体应变分量变化的特性规律,推导出剪切吸水条件下的体变约束条件。不同排水条件下的体变约束条件决定了剪胀性砂土应力-应变响应的不同变化,当满足自由吸水剪切条件时饱和砂土会出现具有流动特征的大变形;当满足强制吸水剪切条件时会发生具有非稳定特征的流滑现象。
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| 关 键 词： | 剪胀性砂土 液化后流滑 排水条件 剪切吸水现象 |
| 收稿时间： | 2009-03-20 |
Post-liquefaction flow failure of saturated dilative sands and its mechanism |
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| ZHANG Jian-min,WANG Fu-qiang.Post-liquefaction flow failure of saturated dilative sands and its mechanism[J].Rock and Soil Mechanics,2010,31(9):2711-2715. |
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| Authors: | ZHANG Jian-min WANG Fu-qiang |
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| Institution: | 1. Institute of Geotechnical Engineering, Tsinghua University, Beijing 100084, China; 2. State Key Laboratory of Hydroscience and Engineering, Tsinghua University, Beijing 100084, China; 3. China Hydropower Engineering Consulting Corporation, Beijing 100011, China |
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| Abstract: | It has been confirmed from completely undrained tests that flow failure is triggered only in saturated contractive sands, while strain hardening or cyclic mobility happened in saturated dilative sands during an application of post-liquefaction monotonic or cyclic shearing. In practice, however, there exist different conditions of drainage in shearing, such as partial drainage and even water absorption initiated in saturated sands under pre- and post-liquefaction loading. Experimental facts show that the large flow deformation can be induced in dilative sands during a post-liquefaction shearing application, only when sufficient magnitude of water-absorption in shearing takes place. The occurrence of large flow deformation is found to depend mainly on a constraint requirement for developments and variations in three kinds of volumetric strain components of saturated sands. Such a constraint condition is also verified to govern different post-liquefaction stress-strain responses of dilative sands. |
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| Keywords: | dilative sands post-liquefaction flow failure drainage condition water-absorption in shearing |
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