桩身外露高度对山区输电线路桩基地震反应的影响

摘要

Steep terrain conditions mountain area of transmission line tower pile foundation often appear a cer-tain height due to the effect of gradient and landform. How pile foundations exposed height and elevation difference will have impact on pile of transmission line in mountain area by earthquake, it is still unclear. Models about pile foundations of transmission line in southwestern mountainous area were computed and analyzed by FLAC3 D. Then seismic response on pile foundations was analyzed, which there is exposed pile height and elevation difference. The results show that:pile peak acceleration, pile displacement, internal force of pile all increased obviously along with increasing exposed pile height. Seismic response will diminished along with decreasing pile foundations elevation difference. For the seismic fortification zone under the condition of steep slope topography provide basis for reasona-ble selection of exposed height of pile.%陡坡地形条件下山区输电线塔桩基础由于受坡度、地形地貌的影响，桩身常外露一定的高度。但塔基各桩的桩身外露高度及高差对桩基的地震反应有什么影响，尚不清楚。以地震作用下受损的西南山区某输电线塔桩基础为研究对象，采用FLAC3D数值分析软件，对桩身不同外露高度、不同高差时桩基础地震动力响应的变化情况进行分析。结果表明：随着桩身外露高度的增加，桩身峰值加速度、桩身位移、桩身内力的量值均有所增大。随着相邻桩基高差的减小，桩基础的地震反应也相应减小，进而为抗震设防区陡坡地形条件下合理的选取桩身外露高度提供一定依据。