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结合工程实测,模拟分析了大型基础下层状砂土地基基底有效附加应力、基础内钢筋应力以及基底竖向变形的变化过程与分布规律。研究结果表明,受基坑降水影响,基底上覆土层有效应力增量对基底沉降的贡献不可忽略;基底压应力不能简单假设为均布荷载,基底最大应力作用点不一定就是最大沉降发生点;基底平面上沉降分布不均匀,基础中心点处的沉降也不一定最大;施工加载期间,基础内钢筋应力呈现交变状态,但钢筋强度发挥有限,仅为其屈服强度的25%;砂土沉降计算经验系数随土层变形模量的增大而减小,但减小幅度不显著。研究结论可为层状砂土地基及其上大型基础设计提供直接参考依据。
Combined with engineering practice, the process and distribution regularity of effective additional stress of basement, rebar stress in foundation and vertical deformation of basement are simulated and analyzed. The results show that the contribution of the effective stress increment of the overburden on the subsidence can not be neglected due to the influence of the foundation pit dewatering. The compressive stress of the basement can not simply be assumed as a uniform load, but the maximum stress point of the basement is not necessarily the maximum subsidence point. The settlement on the base plane is not uniform and the settlement at the foundation center point is not necessarily the maximum. During the loading process, the stress in the foundation assumes an alternating state, but the strength of the rebar is limited to only 25% of its yield strength. The calculated empirical coefficient decreases with the increase of soil deformation modulus, but the decrease is not significant. The conclusion of the study can provide a direct reference for the layered sand foundation and its large-scale foundation design.