黄土地基掏挖扩底基础抗拔试验研究

发布时间：2018-04-15 14:02

本文选题：黄土 + 扩底掏挖基础　；参考：《岩土力学》2014年03期

【摘要】：随着西部电网建设的发展,越来越多的架空输电线路需经过黄土地区。输电线路杆塔基础抗拔能力通常是其设计控制条件。掏挖扩底基础因具有较好的抗拔承载性能而在黄土地区输电线路工程中得到广泛应用。根据甘肃黄土地区2个试验场地12个掏挖扩底基础实测上拔荷载位-移曲线,分别采用Chin双曲线模型以及初始直线斜率法、双直线交点法和L1-L2方法确定了基础抗拔极限承载力及其对应位移,得到了抗拔基础归一化荷载-位移曲线,采用归一化荷载-位移双曲线模型对试验结果进行拟合,给出了不同保证概率下基础荷载-位移预测曲线。结果表明:初始直线斜率法得到的承载力最小,双直线交点法次之,Chin数学模型法最大,宜采用L1-L2方法确定黄土地基掏挖扩底基础抗拔承载性能;荷载-位移曲线归一化处理可显著减小实测荷载-位移曲线的离散性,按双曲线拟合参数a、b均值确定的归一化荷载-位移曲线代表了试验平均值,而试验荷载-位移曲线刚度远大于95%保证概率的预测曲线。
[Abstract]:With the development of western power grid, more and more overhead transmission lines have to pass through loess area.The anti-drawing ability of transmission line tower foundation is usually the design control condition.Excavated and belled foundation is widely used in power transmission line engineering in loess area because of its good uplift bearing capacity.According to the measured uplift load-displacement curves of 12 excavated and expanded foundations in two test sites in loess area of Gansu Province, the Chin hyperbolic model and the initial straight line slope method are used, respectively.The ultimate bearing capacity and its corresponding displacement of the foundation are determined by the double linear intersection method and L1-L2 method. The normalized load-displacement curve of the uplift foundation is obtained, and the test results are fitted by the normalized load-displacement hyperbolic model.The prediction curve of foundation load-displacement under different guaranteed probability is given.The results show that the bearing capacity obtained by the initial straight line slope method is the smallest, followed by the Chin mathematical model method, which is followed by the double linear intersection method. The L1-L2 method is suitable to determine the uplift bearing capacity of the loess foundation.The normalization treatment of load-displacement curve can significantly reduce the discreteness of the measured load-displacement curve. The normalized load-displacement curve determined by the mean value of hyperbolic fitting parameter a / b represents the average value of the test.The stiffness of the test load-displacement curve is much greater than the prediction curve of 95% guaranteed probability.
【作者单位】：中国电力科学研究院输变电工程研究所;中国地质大学(北京)工程技术学院;
【基金】：国家自然科学基金青年基金项目(No.51208480) 国家电网公司科技项目(No.GCB17201200123)
【分类号】：TU444;TU470

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