| 不同级配珊瑚砂水泥胶结体的破坏行为分析 |
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| 引用本文： | 徐东升,黄明,黄佛光,陈成.不同级配珊瑚砂水泥胶结体的破坏行为分析[J].岩土力学,2020,41(5):1531-1539. |
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| 作者姓名： | 徐东升 黄明 黄佛光 陈成 |
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| 作者单位： | 武汉理工大学 土木工程与建筑学院，湖北 武汉 430070 |
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| 基金项目： | 国家自然科学基金（No. 41972271；No. 51508215；No. 51708438）；中央高校基本科研业务费资助（No. 193106001） |
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| 摘 要： | 为探究不同级配的珊瑚砂水泥胶结体在静、动荷载下的破坏行为，利用落锤冲击试验机对不同级配的珊瑚砂水泥胶结体试样进行了一系列冲击试验，并结合静力压缩试验，综合分析了珊瑚砂水泥胶结体的力学行为及破坏形态。试验结果表明：珊瑚砂的级配区间越广，其水泥试块的抗压强度越大、抗冲击性能越强、受冲击破坏程度越小且破碎角逐渐递减；珊瑚砂水泥试块在不同种类的荷载作用下展现出不一样的破坏形态，区别于混凝土试块。在此基础上，建立了三维离散元模型，以模拟的应力-应变曲线与静力试验结果相吻合作为PFC细观参数的选取原则，并利用该细观参数对试块冲击试验进行数值重现。通过细观分析可以看出：从裂隙分布角度分析，随着级配区间越广、平均粒径的增大，均匀且分散的冲击微裂隙会越来越集中往某个方向发展，使得试块的裂缝数量减小、破损程度减轻。从系统黏结力角度分析，级配区间范围窄的试块内部黏结力较小且分布均匀，级配区间范围广的试块内部黏结力较大且分布不均匀。
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| 关 键 词： | 珊瑚砂 级配 冲击荷载 裂缝 离散元方法 |
| 收稿时间： | 2019-06-29 |
| 修稿时间： | 2019-09-09 |
Failure behavior of cemented coral sand with different gradations |
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| XU Dong-sheng,HUANG Ming,HUANG Fo-guang,CHEN Cheng.Failure behavior of cemented coral sand with different gradations[J].Rock and Soil Mechanics,2020,41(5):1531-1539. |
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| Authors: | XU Dong-sheng HUANG Ming HUANG Fo-guang CHEN Cheng |
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| Institution: | School of Civil Engineering and Architecture, Wuhan University of Technology, Wuhan, Hubei430070, China |
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| Abstract: | To investigate the failure behavior of different graded coral sand cementations under static and dynamic loads, a series of impact tests is carried out on the coral sand cementations with different gradations through the drop hammer impact test facility. Combined with static compression tests, the mechanical behavior and failure modes of coral sand cementations are analyzed. The experimental results show that the wider the grading of the coral sand is, the greater the compressive strength of the cement test block is, the stronger the impact resistance is, the smaller the damage angle is, and the crushing angle decreases gradually. The coral sand cement blocks show different failure modes under different kinds of loads, which are obviously different from concrete blocks. Additionally, a 3D discrete element model is established and the paremeters are calibrated according to the the stress-strain curves of the experimental results, then the numerical impact tests are conducted. The numerical results show that, from the perspective of fracture distribution, as the gradation interval and the average particle size increase, the impact-induced micro-fractures that are uniform and dispersed will be more concertraded in a certain direction, leading to the reduction of the number of cracks and the damage degree. From the perspective of system adhesion, the cohesive force inside the block with narrow gradation range is small and distributed uniformly, while the cohesive force in the block with wide gradation size range is large and unevenly distributed. |
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| Keywords: | coral sand gradation impact load crack discrete element method |
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