THREE-PARAMETER MODEL FOR TIME-DEPENDENT BEARING CAPACITY OF PREFORMED PILE IN SOFT SOIL
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摘要: 预制桩承载力的时间效应是岩土工程中一个非常重要且尚未很好解决的问题。在承载力初始增长速率和承载力最大增量的基础上,引入承载力增长半衰期的概念,揭示双曲线模型的数学缺陷。根据机理分析和能量耗散假定,在建立承载力时间效应控制微分方程的基础上,推导出预制桩承载力时间效应的三参数模型。分析表明:该模型可克服双曲线模型的缺陷,双曲线模型及其承载力增长半衰期均是三参数模型对应的特例。最后,通过对两个工程实例的拟合与实测对比进一步验证新模型的正确性。Abstract: The time effect process of bearing capacity of preformed pile is an important and unsolved geotechnical subject.Based on the initial increasing rate and the maximum increment of bearing capacity,half time of bearing capacity process is defined and employed to study the time effect model.Shortcoming of hyperbolic model is validated in terms of it.According to mechanical analysis and some energy dissipating postulates,the governing differential equation for bearing capacity increasing process is developed,and a 3-parameter model for this process is established.Mathematical analysis shows that the hyperbolic model and its half-value time are corresponding degraded expressions of the established 3-parameter model,respectively.The 3-parameter model overcomes the shortcoming of hyperbolic model.Finally,good agreements have been found between simulated results of the proposed model and two field tests.
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Key words:
- preformed pile /
- ultimate bearing capacity /
- time effect /
- energy dissipating /
- differential equation?
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