| 复杂加载条件下珊瑚砂抗液化强度试验研究 |
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| 引用本文： | 马维嘉,陈国兴,吴琪.复杂加载条件下珊瑚砂抗液化强度试验研究[J].岩土力学,2020,41(2):535-542. |
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| 作者姓名： | 马维嘉 陈国兴 吴琪 |
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| 作者单位： | 1. 南京工业大学 岩土工程研究所，江苏 南京 210009；2. 南京工业大学 江苏省土木工程防震技术研究中心，江苏 南京 210009 |
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| 基金项目： | 国家自然科学基金（No. 51678299）；国家重点研发计划项目（No. 2018YFC1504301）。 |
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| 摘 要： | 循环加载方式与应力路径对砂土的抗液化强度有很大的影响。利用GDS空心圆柱扭剪仪对南海珊瑚砂进行了一系列复杂加载条件下均等固结不排水循环试验，探讨了90°突变应力路径下主应力方向角对珊瑚砂抗液化强度的影响。试验结果发现：以循环应力比（CSR）作为应力水平指标，当不控制中主应力系数b的变化时，主应力方向角 对珊瑚砂的抗液化强度并无显著影响；当控制b始终保持0.5时，珊瑚砂的抗液化强度随着 的增加呈现出先减小后增大的趋势，且在 45°时的抗液化强度最低。基于分析循环荷载引起的土单元大、小循环主应力 、 变化，定义了单元体循环应力比（USR）作为一个新的物理指标，发现不同循环加载方式与应力路径条件下施加于珊瑚砂试样的USR与引起液化所需的循环次数NL存在事实上的唯一性关系。通过引自文献的4种无黏性土原始试验数据的再处理，独立地验证了以USR表征砂类土液化强度的适用性。
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| 关 键 词： | 饱和珊瑚砂 复杂循环加载条件 液化强度 单元体循环应力比 |
| 收稿时间： | 2019-01-09 |
| 修稿时间： | 2019-05-12 |
Experimental study on liquefaction resistance
of coral sand under complex loading conditions |
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| MA Wei-jia,CHEN Guo-xing,WU Qi.Experimental study on liquefaction resistance
of coral sand under complex loading conditions[J].Rock and Soil Mechanics,2020,41(2):535-542. |
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| Authors: | MA Wei-jia CHEN Guo-xing WU Qi |
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| Institution: | 1. Institute of Geotechnical Engineering, Nanjing Tech University, Nanjing, Jiangsu 210009, China;
2. Civil Engineering and Earthquake Disaster Prevention Center of Jiangsu Province, Nanjing Tech University, Nanjing, Jiangsu 210009, China |
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| Abstract: | Loading pattern and stress path have great influences on liquefaction resistance of saturated sand. Using GDS hollow cylinder torsion shear apparatus, a series of undrained cyclic loading tests was performed under complex loading conditions on isotropic consolidated saturated coral sand in a Nansha Island, South China Sea. The influence of the inclination angle of principal stress ( ) on liquefaction resistance of coral sand was discussed under 90° jump rotation of principal stress path. It is found that: when the cyclic stress ratio (CSR) is used as the stress level index, has no significant effect on the liquefaction resistance of coral sand as the change in intermediate principal stress coefficient (b) is not controlled; when b always maintains at 0.5, the liquefaction resistance of coral sand shows a tendency to decrease first and then increase with the increase of , and the liquefaction resistance is the lowest when 45°. Based on analyzing the change of the major and minor cyclic principal stresses and caused by complex cyclic loading, a unit cyclic stress ratio (USR) as a new index is defined for cyclic resistance of coral sand. A virtually unique correlation between USR and Nf can be established under different cyclic loading patterns and stress paths considered. The recompiled original experimental data of four types of cohesionless soils in the published literature independently verified the general applicability of USR to characterize liquefaction resistance. |
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| Keywords: | saturated coral sand complex cyclic loading conditions liquefaction resistance unit cyclic stress ratio |
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