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为研究三维地形碎部点平均间距、格网间距等因素对工程土方量测量计算过程中的精度影响,主要通过TLS技术(Terrestrial Laser Scanning Technology,地面三维激光扫描技术)采集数据完整、图形规则、坡度分布均匀的22块大比例尺数字地形区域,以此作为土方量计算的基础数据,分析不同碎部点平均间距、格网间距对土方量精度的影响,得出如下结论:(1)碎部点间距或碎部点密度是影响土方量精度的最主要因素,实际工程中可根据土方量限差要求推求较为适宜的碎部点间距,以提高工作效率,降低生产成本。(2)TLS技术进行土方量测算,点云数据抽稀到5m即可保证相当高的计算精度并兼顾计算效率;全站仪和GNSS RTK技术测算土方量,地形点间距不宜大于15m。(3)对于不同地形测绘技术和不同比例尺情况,土方量计算所选取的格网间距均不应大于10m。(4)航空摄影测量、全站仪和GNSS RTK技术测算工程土方量,须在地形变化复杂区域有意识地增大点密度,以弥补对地形变化描绘的不足。
In order to study the influence of the average distance of the three-dimensional terrain, the grid spacing and other factors on the accuracy of engineering earthwork measurement and calculation, the TLS technology (Terrestrial Laser Scanning Technology) 22 large-scale digital terrain areas with uniform slope distribution were selected as the basic data for earthwork calculation. The influence of the average spacing and the spacing of grids on the earthwork accuracy was analyzed. The conclusions were as follows: (1) Point spacing or broken part density is the most important factor affecting the accuracy of earthwork. In practical engineering, the more suitable spacing of shredded parts can be deduced according to the requirements of earthwork allowance to improve work efficiency and reduce production cost. (2) The earthwork quantity is measured by TLS technology. When the point cloud data is thinned down to 5m, the calculation accuracy is very high and the calculation efficiency is taken into consideration. The total station and GNSS RTK technology can calculate the earthwork amount and the distance between topographic points should not be more than 15m. (3) For different topographic mapping techniques and different scales, the grid spacing selected for earthwork calculation should not exceed 10m. (4) Aerial photogrammetry, total station and GNSS RTK technology measure the amount of earthwork in earthquakes. The density of points must be intentionally increased in the complex terrain to make up for the lack of description of the terrain changes.