共查询到20条相似文献，搜索用时 140 毫秒
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在公路测设中，用切线支距法与弦支距法结合完成曲线测设，并用ＰＣ－１５００机辅助计算，能简化计算过程及正确完成曲线测设。 相似文献
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在公路测设中，用切线支距法与弦支距法结合完成曲线测设，并用ＰＣ—１５００机辅助计算，能简化计算过程及正确完成曲线测设。 相似文献
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介绍在公路导线交点用经纬仪配合钢尺量距，测设公路圆曲线的计算与施测的一种新方法。该法对提高圆曲线测设工作效率、降低劳动强度具有一定的作用。 相似文献
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林区公路圆曲线测设，传统的计算方法是计算器和查表相结合，计算速度慢，容易出错。为了简化计算过程，提高工作效率，争取错误率为零，应用ＫＣ—８５微机，代替传统的计算方法。为此，编制了本程序。本程序适用于林区公路圆曲线测设时的弦支距法，实测时，只需要输入中桩里程、测角度数、选用半径值三个数据，即可计算出所需数据。 相似文献
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本文介绍具有缓和曲线圆曲线的2种测设方法:a.分布测设缓和曲线和圆曲线;b.在直缓点或缓直点1次设站连续测设近端缓和曲线和圆曲线。同时给出2种测设方法的切线支距法和偏角法的公式。 相似文献
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针对林区道路测设条件的特殊性，提出不用经纬仪，而用两把钢尺测设圆曲线细部桩的筒易测设方法。该方法对其科学性进行了分析和探讨，得出了“整桩距”和“整桩号”两种情况下的测设参数——偏支距d的计算公式，并以“整桩号法”为实例阐明了其测设过程。 相似文献
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Michael Craven 《Scandinavian Journal of Forest Research》2014,29(2):174-182
Airborne Light Detection and Ranging (LiDAR) has become a popular remote sensing technology to create digital terrain models and provide forest inventory information. However, little research has been done to investigate the accuracy of using scanning airborne LiDAR to perform road geomatics tasks common to forest engineering. We used airborne LiDAR to estimate existing forest road characteristics in support of a road assessment under four different canopy conditions. In estimating existing road centerlines, LiDAR data had a vertical root mean squared error (RMSE) of 0.28 m and a horizontal RMSE of 1.21 m. Road grades were estimated to within 1% slope of the value sampled in the field and horizontal curve radii were estimated with an average absolute error of 3.17 m. The results suggest that airborne LiDAR is an acceptable data source to estimate forest road centerlines and grades, but some caution should be used in estimating horizontal curve radii, particularly on sharp curves. 相似文献
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Application of an airborne laser scanner to forest road design with accurate earthwork volumes 总被引：1，自引：0，他引：1
In this study we developed a forest road design program based on a high-resolution digital elevation model (DEM) from a light detection and ranging (LIDAR) system. After a designer has located the intersection points on a horizontal plane, the model first generates the horizontal alignment and the ground profile. The model precisely generates cross-sections and accurately calculates earthwork volumes using a high-resolution DEM. The model then optimizes the vertical alignment based on construction and maintenance costs using a heuristic technique known as tabu search. As the distance between cross-sections affects the accuracy of earthwork volume calculations, the results were examined by comparing them with the exact earthwork volume calculated by the probabilistic Monte Carlo simulation method. The earthwork volumes calculated by the Pappus-based method were similar to those calculated by the Monte Carlo simulation when the distance between cross-sections was within 10m. The model was applied to a high-resolution DEM from the LIDAR of Capitol Forest in Washington State, USA. The model generated a horizontal alignment, length 827m, composed of five horizontal curves. We examined the number of grade change points. The results indicated that tabu search found the best solution ($61.42/m) with five grade change points. This was composed of two vertical curves that almost followed the ground profile. As the accuracy of a high-resolution DEM from LIDAR increases, the model would become a useful tool for a forest road designer because it eliminates or at least reduces the time-consuming process of road surveys. 相似文献
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In this study, we combined a program to optimize forest road alignments with a method for prediction of surface erosion and
related sediment delivered to streams. Combining the forest road design program with the high-resolution digital elevation
model made it possible to estimate soil sediment based on a standard methodology, because a relatively accurate road prism
could be generated. The combined program properly places and spaces drainage structures based on the Washington State Forest practice board manual. We applied the program to a part of Capitol State Forest in Washington State and optimized horizontal and vertical alignments
while estimating movement of soil sediment from roads to streams. We discussed the effects of road surface materials, near-stream
culvert distance to stream, and out-sloped forest road template on total road costs and soil sediment delivered to streams.
Using lower quality rock surfacing reduced total costs, but the amount of soil sediment from lower quality rock surfacing
was 1.5 times more than that on a higher quality rock traction surface. Therefore, lower quality rock surfacing should not
be used near the stream. The placement of near-stream culverts 15 m upstream and out-sloped road template were examined using
a traction surface on 15-m sections upstream and lower quality rock surfacing on other sections in order to reduce soil sediments
to the stream and total costs. As a result, placing near-stream culverts 15 m upstream and using an out-sloped road template
significantly reduced total road cost and soil sediment. Finally, we optimized horizontal and vertical alignments while limiting
soil sediment to a specified maximum level. The model successfully optimized forest road alignments, which reduced total road
cost as well as soil sediment. 相似文献
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本文简述了路桥施工测量中放样的四种方法:已知距离的放样,已知水平角的放样、已知高程的放样、平面点位的放样. 相似文献
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冬季冰雪路面行车速度与安全隐患分析 总被引：1，自引：0，他引：1
冬季冰雪路面是交通事故多发的时段,依据车辆特性、视距和道路条件等因素,分析冰雪路面给车辆安全带来的隐患,推导冰雪路面不同能见度、不同坡度和平曲线条件下车辆行驶速度与各因素的关系,给出确定安全车速的方法,为减少冰雪路面交通安全隐患,提高车辆的道路运输安全提供理论依据。 相似文献
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Forest roads require important design specifications to ensure all-season access for various vehicles. Long and heavy log trucks can face serious maneuvering problems on forest roads due to insufficient amount of area to the left for road widening on horizontal curves. In order to provide safe and continuous shipment and transportation,appropriate curve widening areas should be provided for long vehicles along horizontal curves. In this study, a statistical model was developed to provide curve-widening solutions for long trucks(e.g., those with 18 wheels) considering various curve radius and deflection angles. The dynamic curve widening feature of Plateia 2013 program was employed to calculate curve widening for the specified vehicle. During the solution process, nine different horizontal curve diameters from 10 to 50 m(by 5 m intervals)and 17 different deflection angles from 90° to 170°(by 5°intervals) were evaluated to run horizontal curve-widening analysis. Using a multiple regression model, we made suitable predictions about curve widening. The curvewidening areas decrease as the horizontal curve radius increases, while increasing the deflection angle on horizontal curves increases curve widening areas. Clearly, the computer-based dynamic curve widening model developed in this study can be effectively used in determining optimum widening for horizontal curves by evaluating the number of alternatives that fit geometrical specifications and vehicle types. 相似文献
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本文利用道路中线中曲线组成形式.通过数学推证。给出了匝道坐标的计算方法.推导出了计算公式.并通过实例进行了验证.证明此种计算方法实用可行。 相似文献