通过开展砂土中等幅值和变幅值循环加载模型试验,针对空心锥形基础累积位移、转角和水平刚度进行研究。等幅值加载过程中,空心锥形基础沿加载方向减速移动,最终达到稳定状态;基础尺寸和荷载幅值对累积水平位移和转角影响显著,当荷载幅值δb为0.2和0.5时,位移量和倾角随底板直径的增大而增大,而当δb为0.8时,位移量和倾角随底板直径的增大先减小后增大;当δb为0.2、0.5和0.8时,水平刚度随底板直径的增大分别降低39%、59.7%、43.9%。变幅值加载过程中,空心锥形基础在幅值逐级增加时沿加载方向加速移动,水平刚度随基础底板直径的增大先增大后减小,在幅值逐级递减时沿加载方向减速移动,水平刚度随基础底板直径的增大先减小后增大;位移量和倾角在幅值逐级递增时最大,逐级递减次之,等幅值加载最小。通过对无量纲化累积转角拟合,提出等幅值累积转角计算公式,经验证,计算公式与模型试验结果吻合较好。
Abstract
The hollow cone-shaped foundation is a novel onshore wind turbine foundation, which has higher cyclic lateral bearing capacity than the traditional circular gravity-based foundation. A series of lateral cyclic loading tests are carried out to investigate the cyclic bearing behaviors of the hollow cone-shaped foundation with different base plate diameters. The constant-amplitude cyclic loading tests show that the accumulated displacement gradually increases along the loading direction as the number of cycles loading increases, and finally reaches a stable state. The accumulated displacement and rotation angle increase with the increasing the base plate diameter when the load amplitude δb and 0.5, but firstly increases and then decreases when the load amplitude δb. For the cyclic amplitude δb, 0.5, and 0.8, the cyclic stiffness of the hollow cone-shaped foundation decreases by 39%, 59.7%, and 43.9% with the increasing of the base plate diameter, respectively. The variable-amplitude cyclic loading tests show that the accumulated displacement sharply increases along the loading direction, and the cyclic stiffness first increases and then decreases as the load amplitude increases. On the contrary, there is an opposite variation trend as the load amplitude decreases. The formula of calculating the rotation angle of the hollow cone-shaped foundation under constant amplitude cyclic loads is proposed, and the results by using this formula agree well with the model test.
关键词
陆地风电场 /
基础 /
循环荷载 /
等幅值循环 /
变幅值循环 /
累积位移
Key words
onshore wind farms /
foundations /
cyclic loads /
constant-amplitude cyclic loading /
variable-amplitude cyclic loading /
cumulative displacement
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基金
山东省自然科学基金青年基金（ZR2022QE029）; 自主创新科研计划（理工科）-青年基金（22CX06021A）; 青岛市博士后资助项目（ZX20220202）; 山东科技大学科研创新团队项目（2015TDJH104）
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