• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文学位 >Toward modeling erosion on unpaved roads in mountainous northern Thailand.
【24h】

Toward modeling erosion on unpaved roads in mountainous northern Thailand.

机译：在泰国北部山区未铺设的道路上进行模型侵蚀。

获取原文
获取原文并翻译 | 示例
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Contributions of road networks and unstable agricultural activities to downstream sedimentation, water shortages, and flooding in mainland SE Asia are not easily determined because scientific understanding of runoff and erosion processes operating on roads is limited. This dissertation work, conducted within the Pang Khum Experimental Watershed (PKEW) in northern Thailand, supports that owing to low saturated hydraulic conductivity (Ks ≤ 16 min h–1), Horton overland flow (HOF) generation occurs more frequently on unpaved PKEW roads than on other watershed surfaces having higher infiltrability (e.g., mean Ks for agricultural surfaces ranges from 130 to 320 mm h–1). Because of frequent HOF generation, the road system contributes to stream sedimentation throughout the rainy season. The highly compacted (bulk density ≈ 1.45 Mg m –3) PKEW road surface typically underlies a layer of loose material of finite depth. Instantaneous sediment transport (S t) on roads varies because the supply of easily transported surface sediment is constantly altered by overland flow events, traffic, road maintenance, and mass wasting events, both during and between storms. As surface material is removed during an overland flow event, normalized St declines from an initial peak rate of ≈3 g J–1 to a steady rate of ≈0.5 g J–1. The mechanical stress associated with vehicle passes during a storm increases the availability of loose material, producing 2–4 fold increases in St and sediment concentration (Ct) values. Herein, rainfall simulation data, surveys of traffic phenomena, and soil property measurements were used to parameterize the physics-based KINEROS2 model for simulating road runoff and erosion. During model validation, instantaneous discharge was simulated well (root mean squared error (RMSE) = 14%). However, because KINEROS2 equations do not “describe” road erosion processes accurately, St was simulated poorly (RMSE = 51.6%). To improve modeling, a methodology recognizing the dynamic erodibility (DE) of a road surface was introduced. By explicitly simulating removal of a layer of loose material, the DE modeling technique improved prediction of St (RMSE decreased to 35.4%). Finally, a systematic approach is presented to implement DE modeling on any road surface where baseline erodibility and sediment availability can be quantified.
机译：由于对道路上的径流和侵蚀过程的科学认识有限，因此不容易确定道路网络和不稳定的农业活动对东南亚大陆下游沉积，缺水和洪水的影响。这项研究工作在泰国北部的彭坤实验流域（PKEW）中进行，支持了这一点，因为饱和导水率较低（K s ≤16 min h –1 ，霍顿高地流（HOF）的产生在未铺砌的PKEW道路上比在其他具有较高渗透性的分水岭表面上发生的频率更高（例如，农业表面的平均K s 范围为130至320 mm h – 1 ）。由于频繁发生HOF，因此道路系统会在整个雨季促进河流沉降。高度密实（体积密度为1.45 Mg m –3 ）的PKEW路面通常位于一层有限深度的疏松材料之下。道路上的瞬时沉积物运输（S t ）有所不同，因为在暴风雨期间和暴风雨期间和暴雨之间，陆上水流事件，交通，道路维护和大规模浪费事件不断改变易于运输的地表沉积物的供应。由于在陆上水流事件中去除了表面物质，归一化的S t 从最初的峰值速率＆ap; 3 g J –1 下降到稳定的速率＆ap; 0.5 g J –1 。暴风雨期间与车辆通行相关的机械应力增加了散装物料的利用率，使S t 和沉积物浓度（C t ）值增加了2-4倍。在此，使用降雨模拟数据，交通现象调查和土壤性质测量值对基于物理的KINEROS2模型进行参数化，以模拟道路径流和侵蚀。在模型验证期间，可以很好地模拟瞬时放电（均方根误差（RMSE）= 14％）。但是，由于KINEROS2方程无法准确“描述”道路侵蚀过程，因此对S t 的模拟​​效果很差（RMSE = 51.6％）。为了改进建模，引入了一种识别路面动态可蚀性（DE）的方法。通过显式模拟松散材料层的去除，DE建模技术改进了对S t 的预测（RMSE降至35.4％）。最后，提出了一种系统化的方法来在可量化基线侵蚀性和沉积物可利用性的任何路面上实施DE建模。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号