论文部分内容阅读
为了研究细长单桩和多桩在竖向荷载作用下的压曲变形以及非介入性地测量细长桩屈曲引起的土体变形,利用透明土模型试验并结合粒子图像测速(particle image relocimetry,PIV)技术,成功地对不同长宽比以及不同桩数细长桩的屈曲过程进行了试验研究。采用激光照射透明土形成散斑场,并采用单反相机拍摄关心区域的数字图像,利用PIV技术分析图像所获得的位移场。研究结果表明:单桩情况下,桩上下端发生反方向的屈曲变形;多桩条件下,桩下部存在一定的嵌固深度,上部桩身弯曲形式为半个周期的正弦函数;随着长宽比的增加,产生最大横向位移的点不断上移,但是对上半部分桩屈曲变形的范围影响不大;无论在单桩还是多桩条件下,下部土体的水平抗力大于上部土体,从而导致了最大横向位移发生在桩的上半段。
In order to study buckling deformation of slender single pile and multi-pile under vertical load and non-invasive measurement of soil deformation caused by buckling of slender pile, using transparent soil model test combined with particle image velocity measurement (particle image relocimetry, PIV) technique, the buckling process of slender piles with different aspect ratio and different pile numbers has been successfully studied. Speckle fields are formed by irradiating transparent soil with a laser and digital images of the area of interest are taken with a single-lens reflex camera. The displacement field obtained by the image analysis is analyzed by using PIV technology. The results show that under the condition of single pile, the buckling deformation occurs on the upper and lower ends of the pile in opposite directions. Under multi-pile conditions, there is a certain embedded depth in the lower part of the pile, and the bending form of the upper pile is a sine function of half cycle. The increase of the ratio and the point of the maximum lateral displacement keep going up, but the range of the buckling deformation of the upper part of the pile has little effect. The horizontal resistance of the lower part of the soil is greater than that of the upper part of the soil, As a result, the maximum lateral displacement occurs in the upper half of the pile.