偏压固结下软黏土循环强度弱化分析及数值模拟

发布时间：2018-06-25 14:56

本文选题：软黏土 + 循环荷载　；参考：《岩土工程学报》2017年09期

【摘要】：在波浪等循环荷载的作用下,近海工程地基中的软黏土会发生强度弱化,影响上部结构的稳定性。以烟台港的淤泥质粉质黏土为研究对象,进行了动、静三轴试验,探讨不同固结静偏应力和不同循环动应力作用下淤泥质粉质黏土的循环强度弱化规律以及土体循环后不排水剪有效应力路径发展规律。通过对土体循环后不排水剪切过程中有效应力路径的分析,发现当动应力比达到0.4后,土体强度弱化趋势加快,临界有效应力比(M)减小,结构发生一定的破坏,并据此探讨了土体强度弱化机理。此外,基于等效超固结理论,在考虑偏压固结使土体初始有效应力提高的前提下,经过理论推导,得出了考虑初始固结静偏应力和循环效应的土体强度弱化公式,并通过试验数据对其进行验证。最后,通过对ABAQUS的二次开发,利用拟静力算法将该公式应用于烟台港数值模型的有限元计算中。
[Abstract]:Under the action of wave and equal cyclic load, the strength of soft clay in offshore engineering foundation will be weakened, which will affect the stability of superstructure. Taking silt silty clay in Yantai Port as the research object, the dynamic and static triaxial tests were carried out. The law of weakening the cyclic strength of silty clay under the action of different consolidation static deflection stress and different cyclic dynamic stress and the development law of effective stress path of undrained shear after soil circulation are discussed. Through the analysis of the effective stress path in the undrained shear process after soil circulation, it is found that when the dynamic stress ratio reaches 0.4, the weakening trend of soil strength is accelerated, the critical effective stress ratio (M) is decreased, and the structure is destroyed to a certain extent. Based on this, the mechanism of soil strength weakening is discussed. In addition, based on the equivalent overconsolidation theory, the initial effective stress of soil is increased by considering the partial compression consolidation, and through theoretical derivation, the strength weakening formula considering the initial consolidation static deflection stress and cyclic effect is obtained. It is verified by test data. Finally, through the secondary development of Abaqus, the formula is applied to the finite element calculation of Yantai Port numerical model by using quasi-static algorithm.
【作者单位】：天津大学水利工程仿真与安全国家重点实验室高新船舶与深海开发装备协同创新中心;中交第一航务工程勘察设计院有限公司;
【基金】：交通运输部交通建设科技项目(2014328224040) 国家自然科学基金项目(51679166);国家自然科学基金创新研究群体科学基金项目(51321065)
【分类号】：TU442

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