三维激光扫描技术在桥梁变形中的应用研究

发布时间：2018-05-25 14:29

本文选题：三维激光扫描仪 + 桥梁变形　；参考：《兰州交通大学》2017年硕士论文

【摘要】：三维激光扫描仪不间断测点克服了传统测量间断测点的缺陷,其测量速度快,能够获取全景三维模型,表达细节能力强,受环境干扰小,被广泛应用于建筑建模、文物保护等领域,目前逐渐从建模向着变形监测方面发展。三维激光扫描仪可获取连续的点云数据,在进行变形分析时效果显著。本论文运用三维激光扫描仪对桥梁变形进行探究,主要完成以下工作:(1)由于变形监测需要建立高精度的控制网,根据实际建立双大地四边形和大地四边形+三角形两种方案。通过现场实际GPS观测,内业数据处理结果分析,结果为大地四边形+三角形方案精度高于双大地四边形,控制网相对边长中误差达到四等GPS控制网精度。(2)三维激光扫描仪精度影响因素较多:分辨率、扫描距离。首先进行扫描仪分辨率探究。对三种分辨率进行研究:0.0384°(垂)×0.0128°(水);0.0192°×0.0192°;0.0192°×0.0096°,扫描时间分别为9、13、26min,分辨率越大时间越长。数据处理发现随着分辨率增大,点云间隔减小、数量增多,扫描效果提高,但是实际中应根据需要进行选择,本论文试验选择分辨率0.0192°×0.0192°进行扫描。接着对布设的监测点测距分析。在同一测站,设置13min分辨率扫描三次,提取不同距离下三维激光扫描仪获取的监测点坐标,计算点位中误差,得到距离与中误差之间存在二次多项关系式。在40m范围内,点位中误差低于12mm,达到四等变形监测精度。(3)三维激光扫描仪进行监测产生多种误差,数据处理产生的误差主要有坐标转换误差及拼接误差,根据误差来源不同,提出更高精度的匹配模型及削弱措施。(4)分析桥梁变形需有周期性,前后进行三期监测。当荷载作用,变形状况较为复杂,主要分析竖向即Z值的变化。第一期与第二期由于荷载较为接近,结果也比较相近;第一期与第三期、第二期与第三期相比,明显可以看出随着荷载增大,变形量也加大。同样桥墩变形也可以看出,荷载增大,变形值也增大。本次试验探究了三维激光扫描技术在桥梁变形监测中的应用研究,为三维激光扫描仪今后在桥梁变形监测方面提供参考和借鉴。
[Abstract]:The 3D laser scanner overcomes the shortcomings of the traditional measurement of the discontinuous point, its measuring speed is fast, it can obtain the panoramic 3D model, the ability of expressing details is strong, and it is less interfered by the environment, so it is widely used in architectural modeling. At present, the field of cultural relic protection is gradually developing from modeling to deformation monitoring. The 3D laser scanner can obtain continuous point cloud data, and it is effective in deformation analysis. In this paper, a 3D laser scanner is used to study the deformation of the bridge. The following work is accomplished: 1) since deformation monitoring needs to establish a high-precision control network, two schemes of bi-geodetic quadrilateral and geodetic quadrilateral triangle are established according to the actual situation. Through the field GPS observation and the analysis of the data processing results, the result shows that the precision of the geodetic quadrilateral triangle scheme is higher than that of the dual geodetic quadrangle. There are many factors affecting the accuracy of 3D laser scanner: resolution, scanning distance. First, the resolution of the scanner is explored. The three kinds of resolutions are studied. The resolution is 0.0384 掳(vertical) 脳 0.0128 掳(water) 0.0192 掳脳 0.0192 掳(0.0192 掳脳 0.0096 掳). The scanning time is 9 ~ 1313 ~ (26) min, and the longer the resolution is, the longer the resolution is. Data processing shows that with the increase of resolution, the number of cloud points decreases, the number increases, and the scanning effect is improved. However, the selection should be made according to the need in practice. In this paper, the resolution of 0.0192 掳脳 0.0192 掳is chosen to scan. Then the location of the monitoring points is analyzed. In the same station, 13min resolution scanning is set three times, the coordinates of monitoring points obtained by 3D laser scanner at different distances are extracted, the center error of points is calculated, and the quadratic multiple relation between distance and center error is obtained. In the range of 40m, the center error of point position is less than 12mm, which reaches the accuracy of fourth grade deformation monitoring. The 3D laser scanner produces many kinds of errors. The errors produced by data processing mainly include coordinate conversion error and splicing error, according to the error sources, the error is different. A more accurate matching model and its weakening measures are put forward. The analysis of bridge deformation needs periodicity and three phases of monitoring before and after. When the load action, the deformation condition is more complex, mainly analyzes the vertical direction, namely Z value change. The results of the first phase and the second phase are similar because of the close load, and the first and the third phase, the second phase and the third phase, obviously show that the deformation increases with the increase of the load. The same pier deformation can also be seen, load increases, deformation value also increases. This experiment explores the application of 3D laser scanning technology in bridge deformation monitoring and provides reference for 3D laser scanner in bridge deformation monitoring in the future.
【学位授予单位】：兰州交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U446

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