塔克拉玛干沙漠输电线塔装配式基础试验研究

Experimental study of assembly foundation for transmission line tower in Taklimakan desert

为研究新疆塔克拉玛干沙漠地区输电线路工程中的组合装配式杆塔基础承载特性,开展了2种尺寸规格共4个基础在上拔与水平力组合作用下的现场试验,得到了基础顶部和基础底板的荷载-位移曲线、基础底板土压力变化规律。结果表明:上拔与水平力组合作用下,基础顶部上拔荷载-位移曲线为缓变型、水平荷载-位移曲线近似为直线;由混凝土底板和角钢支架所构成的组合装配式基础因自重轻、基础底板上覆沙体结构松散,使得基础的抗倾覆承载能力低。由混凝土底板和角钢支架组成的装配式基础各部件具有良好的协同工作性能,但水平荷载对装配式基础的承载性能影响大。根据基础上拔极限承载力试验值,采用柱式破裂面力学计算模型得到风加沙柱面平均摩擦阻力为2.6 kPa。

In order to obtain the performance of assembly foundations composed by the concrete footing slab and steel angle column, which are used for the transmission line engineering in Taklimakan desert, the four in-site full-scale of two sizes tests on the bearing capacity of assembly foundations combined uplift with horizontal loadings are carried out. The curves of load-displacement both of footing slab and foundation top plane, and the soil pressure on the footing slab are all obtained. For the foundation top plane, combined the uplift with horizontal loadings, the curve of uplift loading-displacement develops slowly; and the curve of horizontal loading-displacement increases linearly. The anti-overturning bearing capacity of assembly foundation is weak because of light dead weight of the steel support frame and the loose property of aeolian sand. The assembly foundation composed by concrete footing slab and steel angle column has a good property of coordinated performance. Influence of horizontal loading on bearing capacity of assembly foundation is obvious. According to the test data of ultimate uplift bearing capacity, the average frictional resistance of aeolian sand is 2.6 kPa, which is calculated by mechanical model of prismatic fracture plane.