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斜坡地基中杆塔基础抗拔承载特性是目前输电线路工程中亟待解决的关键技术难题之一,而目前的相关成果仅停留在理论分析中,并无试验数据支撑。本文以输电线路中常用的掏挖基础为研究对象,在20#斜坡地基中开展了直柱、扩底两种结构型式的全尺寸基础上拔静载试验,获得试验基础荷载位移曲线、地基土压力、地表土体裂缝等数据,对比分析了两种型式的基础在变形特征、破坏模式、抗拔承载力构成等方面的差异。结果表明:直柱基础荷载位移曲线呈陡降型,扩底基础呈缓变型,且扩底基础抗拔承载力是直柱基础的2.5倍;沿坡向两侧土体在变形和破坏特征方面均存在差异,这种差异是由两侧土体有效抗拔深度不同所致;基础抗拔承载力的三个组成部分基础自重、扩大头处土抗力(直柱基础这部分为0)、基柱侧摩阻力在加载过程中发挥程度存在明显的阶段性差异。
Uplift and bearing capacity of tower foundation in slope foundation is one of the key technical problems that urgently need to be solved in transmission line engineering. At present, the related achievements only stay in the theoretical analysis, and there is no test data support. In this paper, the excavation foundation commonly used in power transmission lines is taken as the research object. In the foundation of 20 # slope, full-scale pull-out tests are carried out for two types of structures, and the experimental foundation load displacement curve is obtained. Pressure, surface soil and so on. The differences between the two types of foundation in deformation characteristics, failure modes and the composition of anti-pull bearing capacity are analyzed. The results show that the vertical load-displacement curve of the straight column shows a steep descending type, the foundation of the expanded bottom is a slowly changing type, and the ultimate pull-out carrying capacity of the expanded base is 2.5 times that of the straight column. The deformation and failure characteristics of the soil along both sides of the slope The difference is caused by the difference of effective depth of pull-up between the two sides of the soil. The three components of the basic pull-out bearing capacity are based on their own weight and expand the resistance of the head (the part of the straight column is 0) Column friction has a significant stage difference in the loading process.