层状软粘土地基承载力简化计算方法的研究

摘要

在港口与近海工程中,海洋地基大多由层状软粘土构成,并且各土层的强度参数差别非常大.目前,在工程实践中大多采用近似的计算方法或经验公式计算层状粘土地基的极限承载力,如扩散角法、冲剪破坏理论、Brown&Meyerhof的经验公式等.由于层状粘土地基的破坏模式、极限承载力与土层的厚度、土体强度密切相关,上面这些公式无法准确地预测层状粘土地基的极限承载力.文章基于有限元数值计算分析软件ABAQUS,进行了大量的对比计算,揭示了层状软粘土地基的破坏模式、极限承载力与土层的厚度、土体强度等影响因数之间的依赖关系;基于计算结果,给出了临界深度的计算公式;建立了有效、实用的承载力简化计算公式与计算图表,可为相关工程设计提供参考.%In harbor and offshore engineering, the seabed is often consisted of distinct layers with significant different properties.In recent years, some approximate solutions have been presented in an attempt to calculate the ultimate bearing capacity of layered clays, including the projected area method, the punching shear method and the empirical expressions (Brown&Meyerhof, 1969).For layered clay profile, the failure mechanisms are closely re-lated to the depth of upper layer and the strength of each layer.Therefore, all of the above formulas are not able to provide accepted results of the ultimate bearing capacity of layered clays.In this paper, according to lots of calcula-tion results by finite element analysis software ABAQUS, the relationship between the ultimate bearing capacity and the depth and strength of layer was illustrated.Based on the results from numerical calculation, a simplified formula was proposed to evaluate the critical depth.