戈壁滩输电线路碎石土地基全掏挖基础试验研究

Experimental study on excavated foundation of transmission line gravelly soils in gobi area of Northwest China

针对西北地区戈壁滩输电线路碎石土地基,在国内大规模开展了全掏挖基础的现场真型试验,对其可行的施工工艺进行了探讨,着重对其极限承载力和基础的变形性状进行了研究分析,提出了经验计算公式,给出了相关计算参数的取值,并对其经济环保效益进行了比较。试验结果表明,戈壁滩地区碎石土地基全掏挖基础的极限抗拔承载力由基础自重、计算剪切面内土体自重和计算剪切面上剪阻力的垂直分量三部分构成,研究成果为全掏挖基础在戈壁滩输电线路碎石土地基中的设计提供了参考,可在西北地区750 kV同塔双回紧凑型输电线路杆塔基础中推广应用。

With regard to the transmission line gravelly soil foundation in the gobi area of Northwest China, the full-excavated foundation field prototype tests are carried out to measure the foundation deformations and load bearing capabilities under various working conditions. The feasible construction technology and procedure are discussed. Field mechanism and methods for calculating the uplift bearing capacity are suggested. The empirical calculation formulas and the reasonable design parameters are summarized. The economical benefits of excavated foundation and traditional large digged formation are compared. The environmental advantages of excavated foundation and rigid concrete foundation are analyzed. Based on the test results, the components of the uplift bearing capacity to excavated foundation in the gobi area of Northwest China are put forward： base weight, earth mass weight in the predicted failure plane, and vertical components of shear resistance above the predicted failure plane. The experimental results provide a basis for the design and application of 750 kV compact power transmission line with double circuits on the same tower in Northwest China.