数字近景摄影测量在监测节制闸动态变形中的应用

为了监测节制闸在闸门升降期间的瞬间变形,及时掌握节制闸结构的整体变形信息,为评估节制闸的运行状态提供数据支持,采用数字摄影技术完成节制闸结构的瞬间变形监测。利用外业数据采集设备非量测数码相机,在闸门升起之前拍摄一张像片作为零像片,在闸门升起过程中拍摄的照片作为后继像片。通过比较后继像片与零像片得到同名点的像素变化值,根据参考点间的基线数据,采用空间时间基线视差法将变形监测点的像素变化值转化成实际位移值,并绘制节制闸的变形走向图。结果表明:采用数字摄影技术的相对测量精度达到3/1000,能够满足变形监测的精度要求。由变形走向图可知,各个变形点的变形走向是一致的,没有局部失稳的现象发生,且洪园节制闸处于弹性变形内,最大变形不超过5.00 mm,节制闸是安全的。本研究对当前水利工程结构无接触实时安全监测做出补充,对未来工程结构的安全监测的发展具有一定的推动作用。

Application of digital close-range photogrammetry in the deformation observation of check gate

The digital photography technology was used to complete the transient deformation observation of the check gate during gate lift to grasp the whole information of check gate in time and provide data support for evaluating check gate. The external data acquisition equipment—the digital camera was used to take a picture as a zero photo before the gate rising. Photos were taken as subsequent photos in the process of gate lift. The changed pixel value of the same name point was obtained by comparing the subsequent photos with the zero photo. Based on baseline data of the reference point, the actual displacement value was obtained by using the spatial time baseline parallax method, and deformation trend diagram was drawn. Results showed that the relative measurement accuracy of digital photography was 3/1 000, which could meet the requirements of deformation monitoring. According to deformation trend diagram, each deformation point moved consistently with each other, and no local instability occurred. Hongyuan check gate was within elastic deformation. The maximum deformation was less than 5.5 mm, the deformation was within safe levels. This study was a ful supplement for the current real-time safety monitoring of hydraulic engineering structure, which could promote the development of safety monitoring of engineering structure in the future.