湿陷性黄土场地风电基桩水平承载特性试验研究

Experimental study on horizontal bearing capacity of wind power foundation piles in collapsible loess site

为探究黄土湿陷性对风电基桩水平承载特性的影响,在陕西省定边县某黄土场地设置3根试桩进行水平载荷试验,其中1根桩周土保持天然状态,2根桩周土在加载前已经浸水饱和且湿陷稳定。分析了各级水平荷载作用下两类试桩桩顶水平位移、桩身弯矩及其分布范围、水平抗力系数的比例系数m值的差异。试验结果表明:桩周土饱和湿陷明显增大了桩的水平位移,随着水平荷载增加这种现象更为显著;桩周土饱和湿陷时的桩身弯矩大小及其分布范围均比桩周土天然状态时大;幂函数能够较好地反映不同桩顶水平位移与m值之间关系,可以通过建立幂函数以获取m值及其相应单桩在地面处水平位移的对应关系。

In order to explore the effect of loess collapsibility on the horizontal bearing characteristics of wind power foundation piles,three test piles were set up in a loess site in Dingbian County,Shaanxi Province for horizontal load tests.Among them,the surrounding soil of 1 pile remains in its natural state,and the surrounding soil of 2 piles has been saturated with water and has stable collapsibility before loading.The differences of the horizontal displacement of the pile top,the bending moment of the pile body and its distribution range,and the scaling factor for horizontal resistance factor m value of the two types of test piles under the action of horizontal loads at all levels were analyzed.The test results show that the saturated collapsibility of the soil around the pile significantly increases the horizontal displacement of the pile,and this phenomenon is more significant with the increase of the horizontal load.The magnitude and distribution range of the bending moment of the pile body when the soil around the pile is saturated and collapsible are larger than those when the soil around the pile is in the natural state.The power function can better reflect the relationship between the horizontal displacement of pile tops and the m value,and the corresponding relationship between the m value and the horizontal displacement of the corresponding single pile on the ground can be obtained by establishing a power function.