Application of an airborne laser scanner to forest road design with accurate earthwork volumes   总被引：1，自引：0，他引：1  

Kazuhiro Aruga  John Sessions  Abdullah E. Akay 《Journal of Forest Research》2005,10(2):113-123

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   

森林火点定位报警系统设计与开发     

蒋国华  何迪 《林业勘查设计》2007,(3):74-76

清远市地处粤北山区,跨中亚热带、南亚热带,森林资源十分丰富。清远市境内森林火灾比较频繁,全市平均每年烧山29.4次,年平均受灾面积为304.8hm2,损失较为严重。森林火点定位报警系统能够在监测到火点时及时报警通知值班人员,快捷直观地显示火点的位置,并将火点发生的时间、经度、纬度、象素等信息存入数据库,提供相应的查询功能。  相似文献   

麦克哈格的整体性规划思想研究——以伍德兰兹社区生态规划项目为例     

刘邑君  高伟 《广东园林》2020,42(5):81-86

以经典案例——伍德兰兹社区生态规划思路为例,探讨麦克哈格(Ian McHarg)的整体性设计思想。研究以规划文本中的“生态清单”作为研究对象,凝练麦克哈格的整体性思想,并结合其提出的规划设计框架,总结出适用于当今风景园林规划设计的场地生态因子及其对应指标的整体性框架,揭示了麦克哈格的规划设计智慧——在规划设计中需要从整体性思想的角度考虑场地的全要素,其中包括生态因子之间与设计要素之间的互动耦合关系,才能得出与真实世界中的复杂性问题相匹配的规划设计方案。  相似文献   

意大利214杨林地施肥效应研究   总被引：7，自引：0，他引：7  

刘寿坡  南健德 《林业科学》1990,26(6):485-494

本项试验按正交设计,试验观测历时7年,从苗木栽植直至林木工艺成熟,对林分生长全过程进行了定期观测及系统研究。其主要结论是:在较贫瘠的土壤上进行林地施肥,对Ⅰ-214杨有明显的增产效应,与对照区相比,施肥区材积最大增长量达132％。在不同肥料中氮肥效应突出,氮、磷、钾及绿肥压青合理配合,能取得增产的最佳效果。  相似文献   

国产人造板宽带砂光机功率谱密度和试验模态分析   总被引：3，自引：0，他引：3  

王正  朱典想 《林业科学》2005,41(6):132-137

以国产B229型四四砂架人造板双面宽带砂光机为研究对象,从易产生横纹缺陷入手,对其砂架部件、整机等分别采用试验模态分析(EMA)及功率谱密度法(PSD)来开展振动动态特性研究。在模态试验中,采取测量点固定、改变激振点的跑点测量方法,得到固定测量点对各激振点频响函数,并应用SISO频响函数识别法,通过频响函数曲线拟合来完成模态参数识别,获到典型的整机、砂架部件的频响函数图和接触辊的二阶振型图。通过PSD分析,获得砂光机的PSD图谱和激励频率等。  相似文献   

寒地城市广场设计计划     

崔德军  何松峻 《林业科技情报》2001,33(2):38-38

作者对北方寒冷城市的广场设计问题进行了分析研究,并提出了一些观点和想法,对北方城市广场的设计问题提出一些新的思路。  相似文献   

林区公路线形设计浅谈     

苏江 《林业科技情报》2006,38(1):86-87

本文作者结合自己多年的工程实践,对林区公路线形设计进行了论述,并提出了一些理论与实践相结合的方法。  相似文献   

机械零件二维与三维一体化设计程序的开发     

李鹏  陶毓博  战剑锋 《林业机械与木工设备》2004,32(9):28-30

介绍了在AutoCAD设计系统中,机械零件二维与三维一体化设计程序的开发方法。利用这个方法,设计者在完成机械零件三维模型设计后,可以快速获得零件施工图。  相似文献   

林区公路设计中容许弯沉值的计算分析     

鲍明伟 《林业科学》1993,29(1):86-90

目前,林区公路大多为就地取材的中、低级路面,因而结构设计很少,而厚度设计则是主要的内容。在厚度设计中,是根据对公路整体强度的要求来确定各结构层厚度的,确定的依据就是路面容许弯沉值。一、容许弯沉值及其计算公式容许弯沉值指标一般应在大量调查的基础上,根据林区公路的现状和可能的条件,考虑林业经济发展对林区公路将来的要求,而提出相应的数值。国内外通过大量的调查试验和研究,认为容许弯沉值主要由交通量数值确定。一般来说,等级越高的公路,通过的交通量也越大,但考虑到不同等级公路的不同的要求,不完全是体现于交通量;同时现在采用的路面类型越来越多,不同类型的路面对变形有不同的适应能力,如目前较多采用的  相似文献   

Critical discussion of perpendicular to grain tension testing of structural timber – case study on the European hardwoods ash,beech and maple     

Philipp Schlotzhauer  Alexander Ehrmann  Susanne Bollmus  Holger Militz 《Wood material science & engineering》2020,15(5):278-288

ABSTRACT

Knowledge about perpendicular to grain tension behavior of wood is essential, since in construction tension stresses perpendicular to grain cannot be avoided completely. Especially for hardwoods, the data basis is scarce. EN 338 design values are with 0.6 N/mm² characteristic strength set very low. The US-American National Design Specifications even set this value to zero and make local reinforcements mandatory. This paper compares strength and stiffness values attained with newly-designed, little, prismatic specimens and EN 408 structural timber specimens to evaluate the current European design values. Little specimen’s characteristic strength values range from 7.2 to 10.6?N/mm² and are assumed to be real material properties. EN 408 specimen values are with approximately 4.0?N/mm² lower. These lower values are mainly due to stress peaks introduced by the force introduction. Strength values attained for the medium-dense European hardwoods beech, ash and maple exceed EN 338 design values by a factor of six to seven. Adaptation of the EN 338 design value is not recommended, though. The abundance of influencing factors makes clear that the design value and the ensuing design code have to be synchronized carefully by tedious testing in order to make use of the perpendicular to grain tension strength potential of the selected hardwoods.  相似文献