基础尺寸对碎石土地基扩底基础上拔承载力影响的现场试验研究

发布时间：2018-07-23 12:38

【摘要】：影响基础上拔承载能力的因素包括地基土物理力学参数及基础尺寸参数,而确定混凝土方量最小、基础上拔承载力最大的基础参数配比是基础优化设计的关键。以戈壁滩碎石土地基中的原状土扩底基础为研究对象,采用正交设计方法,以立柱直径、深宽比、扩展角为影响因素,以基础上拔承载力为分析指标,设计出9组尺寸的足尺基础。通过现场试验,获得了各试验基础的荷载位移曲线和上拔承载力值,提出了采用渐变率的概念表征荷载位移曲线的非线性变化特征,通过分析发现基础荷载位移曲线渐变率与承载能力呈负相关。结合正交试验分析结果,得出立柱直径、深宽比、扩展角3个因素中对碎石土地基原状土扩底基础抗拔承载能力的影响程度由大到小依次为深宽比、立柱直径、扩展角,表明在戈壁滩碎石土地基基础的工程设计中增加深宽比能提高基础抗拔承载能力。
[Abstract]:The factors that affect the bearing capacity of foundation are physical and mechanical parameters of foundation soil and parameters of foundation size. The key to the optimization design of foundation is to determine the proportion of foundation parameters with the smallest concrete volume and the maximum uplift capacity of foundation. Taking the foundation of undisturbed soil in the gravel foundation of the Gobi Desert as the research object, adopting the orthogonal design method, taking the diameter of the column, the ratio of depth to width and the angle of expansion as the influencing factors, and taking the uplift bearing capacity of the foundation as the analysis index, Nine groups of full-scale foundation are designed. The load-displacement curves and uplift bearing capacity values of each test foundation are obtained through field tests. The concept of gradient rate is proposed to characterize the nonlinear variation characteristics of load-displacement curves. It is found that there is a negative correlation between load displacement curve gradient rate and bearing capacity. Combined with the results of orthogonal test, it is concluded that the influence of three factors on the uplift bearing capacity of the undisturbed foundation of crushed stone foundation is the ratio of depth to width, the diameter of column, the angle of expansion, among the three factors: diameter of column, ratio of depth to width and angle of expansion. It is shown that the uplift bearing capacity of the foundation can be improved by increasing the ratio of depth to width in the engineering design of the gravel foundation in the Gobi Desert.
【作者单位】：中国电力科学研究院;甘肃省电力设计院;
【基金】：国家电网公司科技项目(GCB17201400162)~~
【分类号】：TU476

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