饱和珊瑚砂三轴蠕变特性及经验模型
Triaxial creep characteristics and empirical model for saturated coral sand
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摘要: 对饱和珊瑚砂进行不同围压和偏应力水平下的三轴排水蠕变试验,结果显示:围压和偏应力对蠕变变形影响显著,具体表现为偏应力较大或围压较小时,蠕变形变量较大,蠕变现象明显。采用传统的Singh-Mitchell及Mesri蠕变模型描述珊瑚砂蠕变特性,发现两者在高偏应力条件下模型计算结果与试验结果相差较大,无法准确描述珊瑚砂的蠕变行为。通过分析模型与试验结果误差较大的原因,并将应力-应变及应变-时间关系均采用双曲线函数表示,建立了一个新的蠕变模型,且新模型预测结果与试验结果一致性较好。Abstract: The riaxial drainage creep tests are performed on saturated coral sand under different cell pressures and deviator stress levels. The results show that the cell pressure and deviator stress have significant effects on creep deformation. The specific performance is that when the deviator stress is large or the cell pressure is small, the creep deformation is large, and the creep phenomenon is obvious. The traditional Singh-Mitchell and Mesri creep models are used to describe the creep characteristics of coral sand. It is found that the calculated results of the two models are quite different from the test results under high deviator stress conditions, which cannot accurately describe the creep behavior of the coral sand. By analyzing the reasons for the large error between the model and the test results, the stress-strain and strain-time relationships are expressed by hyperbolic functions, and a new creep model is established. The predicted results of the new model are in good agreement with the test results.