煤矿采空区基础变形特高压输电塔的承载力计算

Bearing Capacity Computation of UHV Transmission Tower With Foundation Deformation Above Coaf of Goal Mine

煤矿采空区铁塔基础易发生变形,严重威胁特高压输电线路的运行安全。采用通用有限元软件ANSYS建立1000kV特高压输电铁塔有限元模型,对采空区铁塔在基础发生沉降、倾斜或滑移后,与正常设计工况进行组合时杆件的内力及其变化趋势进行计算分析,确定了不同工况下的基础变形限值。结果表明,在外荷载相同的情况下,基础位移限值由大到小的顺序为:顺线路变形、横线路变形、不均匀沉降和基础滑移。60°大风工况下基础变形限值最小,为铁塔基础变形的控制工况。与现行规程相比,计算得到的基础不均匀沉降限值偏低,依照规程限值判断铁塔受力状况偏于危险。基础位移未超过限值时对铁塔进行扶正,除基础水平滑移情况以外,铁塔杆件内力未超过极限承载力,处于安全状态。研究结果为我国煤矿采空区基础变形特高压输电线路的安全运行提供参考依据。

The tower foundation above goaf of coal mine is easily deformed, which causes serious threat to the safe operation of UHV transmission lines. In this paper, the finite element model of 1 000kV transmission tower was established, and the internal member forces as well as their variation trends were analyzed under foundation settehnent, slip and inclination combined with normal design conditions. The limitations of foundation deformation under different conditions were determined. It shows that the limitations of longitudinal deformation, tranverse deformation, non-uniform settlement and horizontal slip are decreased in above turn when with the same external loads. The foundation deformation under condition of the wind with 60 degree is the lowest, which is the control condition of foundation deformation. The limitation of non-uniform settelment through computation is lower than the provision in the current regulation, and it is dangerous to evaluate the stress state according to the regulation. In the righting process of the tower, the internal member forces aren＇t over than the critical bearing capacities except the horizontal slip, and the tower is in a safe state. The research results provide very important reference and basis for the safe operation of UHV transmission lines in the goaf area of coal mine.