大型基础下层状砂土静力变形性状测试  

DEFORMATION TESTING OF LAYERED SANDY SOIL UNDER LARGE FOUNDATION DUE TO STATIC ADDITIONAL LOAD

作　　者：李纯[1] 张淼[1] 付诗梦[1] 朱浮声[1] 

机构地区：[1]东北大学资源与土木工程学院,辽宁沈阳110819

出　　处：《工程力学》2013年第8期217-222,共6页Engineering Mechanics

基　　金：国家自然科学重大基金项目(90915005)

摘　　要：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。The process of change and distribution of effective additional stress acting on a foundation base, the tensile stress of foundation concrete reinforcing bars and vertical deformation of foundation soil were investigated via methods of field monitor and data analysis. It shows that the contribution to settlement, influenced by dewatering of foundation pit, made by effective stress increment of soils overlying foundation base, should not be neglected; that the compressive stress acting on foundation base cannot be simply assumed as a uniform load, and the situation of the largest vertical deformation occurring does not keep in line with the working point of the largest stress; that the settlement values of foundation base in different places are usually different, and settlement at the centre of a large foundation maybe not the largest; that during the period of construction, the tensile stress of concrete reinforcing bars changed with time alternately, and the maximum tensile stress is just about 25%, which is far lower than the allowable strength of the reinforcing bars. The modulus of deformation of deeper sandy soil is usually larger than that of shallower sandy soil, but the empirical coefficient of settlement calculation of deeper sandy soil is smaller than that of shallower sandy soil. The conclusions mentioned above can offer a reference to the design of large concrete footing and layered sandy foundation bases.

关 键 词：层状砂土地基 交变应力 变形 有效附加应力 软弱夹层 

分 类 号：TU740[建筑科学—建筑技术科学]