摘要
为了满足长江南岸的用电需求,跨长江输电塔的建设规模不断扩大。依托江苏凤城至梅里385 m高的大跨越工程,开展精细化三维有限元数值模拟,系统研究了风速、风向角、土层参数和桩径对大跨越塔桩基变形特性的影响。发现风荷载作用下,大跨越塔所受的最大拉力和压力均位于塔脚位置。45°、60°风向对跨越塔桩基影响最大,45°、60°风向引起的桩基水平位移和沉降比0°、90°风向工况大13.0%和26.9%。上部土层压缩模量增加一倍后,风荷载引起的桩基最大水平位移降幅高达28.9%,而黏聚力增加一倍后桩基最大水平位移降幅不到3%。随着跨越塔桩基直径的增加,风荷载引起的桩基水平位移不断降低;但是桩径从1.4 m增至2.0 m后,桩基最大水平位移降幅不足10%。相比于采取大直径桩,上部软土层加固能更好地限制风荷载引起的桩基位移。研究成果为跨长江输电塔桩基设计提供一定的指导。
More and more transmission towers were constructed across Yangzi River channel to meet power demand for residents and industries.Based on the 385 m high long span project from Fengcheng to Meili in Jiangsu Province,three-dimensional numerical simulation was carried out to systematically investigate the effects of wind speed,wind angle,soil parameters and pile diameter on deformation characteristics of pile foundation of large span tower.It is found that wind induced the maximum tension and compressive forces are located at the foot of large span tower.The wind with angles of 45°and 60°has the greatest impacts on pile foundation.The horizontal displacement and settlement of pile foundation caused by wind with angles of 45°and 60°are 12.4%and 45.0%greater than those caused by wind with angles 0°and 90°wind angles.By increasing soil compression modulus by 100%,wind-induced maximum horizontal displacement of pile foundation is as high as 28.9%.However,the maximum horizontal displacement of pile foundation is only reduced by less than 3%when soil cohesion is doubled.As the pile diameter of transmission tower is increased,wind-induced horizontal displacement of pile foundation is decreased,but at a reduced rate.When the pile diameter is increased from 1.4 to 2.0 m,the reduction in the maximum horizontal displacement of pile foundation is less than 10%.Thus,the pile displacement can be effectively restrained by solidifying upper soft clay rather than using lager diameter pile.The research findings from this study can provide some guidance for the design of pile foundation for transmission tower across the Yangtze River.
作者
宁帅朋
余亮
李布辉
倪小东
史江伟
NING Shuai-peng;YU Liang;LI Bu-hui;NI Xiao-dong;SHI Jiang-wei(China Energy Engineering Group Jiangsu Power Design Institute Co. Ltd., Nanjing 210000, China;Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering, Hohai University, Nanjing 210024, China)
出处
《水道港口》
2022年第1期114-120,共7页
Journal of Waterway and Harbor
基金
国家自然科学基金项目(51779083)。
关键词
大跨越
桩基
风向角
风速
三维变形
large span foundation
pile foundation
wind direction
wind velocity
three-dimensional deformation
