Evaluation of gravel sphericity and roundness based on surface-area measurement with a laser scanner
Evaluation of gravel sphericity and roundness based on surface-area measurement with a laser scanner
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DOI：
10.1016/j.cageo.2005.01.004
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发表时间：
2005-07-01
影响因子：
4.4
通讯作者：
Oguchi, T
中科院分区：
文献类型：
--
作者：
Hayakawa, Y;Oguchi, T
在沉积学和地貌学研究中，球度和圆度被用来表示砾石颗粒的总体形状。最初对砾石球度和圆度的复杂定义导致了可视化图表或简化参数的使用。虽然精确计算球度需要砾石颗粒的表面积，但手工测量表面积是极其困难的。利用激光扫描仪建立了砾石颗粒的三维数字模型，获得了砾石颗粒的表面积，并根据原始定义计算了球形度。扫描的砾石样本是从日本中部的一条河床上采集的，包括各种形状，从棱角分明的到圆润的。尽管球度和圆度一直被认为是不同的概念，但获得的真实球度值与Klambein的圆度显示出出人意料的高度相关性。这种高相关性可能会降低其中一个参数的值。由于砾石颗粒在自然界中很少出现，本文提出了一个新的参数--真球度修正，来表示砾石形状与给定轴长的椭球体的偏差。该参数与圆度和砾石大小的相关性很弱，表明该参数具有独立性和潜在的实用性。表面积数据还允许在不使用直观图表的情况下估计砾石圆度。(C)2005爱思唯尔有限公司。保留所有权利。
Sphericity and roundness have been employed in sedimentological and geomorphological studies to represent the gross shape of a gravel particle. The original complex definitions of gravel sphericity and roundness led to the use of visual charts or simplified parameters. Although the accurate derivation of sphericity requires the surface area of a gravel particle, manual measurement of the area is extremely difficult. To obtain the surface area and to calculate sphericity based on the original definition, 3D digital models of gravel particles were constructed using a laser scanner. The scanned gravel samples, collected from a riverbed in central Japan, include various shapes from angular to well-rounded. The obtained true sphericity values show an unexpectedly high correlation with Krumbein's roundness, despite that sphericity and roundness have been regarded as different concepts. Such a high correlation may reduce the value of one of the parameters. As a spherical particle of gravel rarely occurs in nature, a new parameter, a modification of the true sphericity, is proposed to express the deviation of gravel shape from an ellipsoid with given axis lengths. The parameter has a very weak correlation with roundness and gravel size, suggesting its independence and potential usefulness. The surface area data also permit the estimation of gravel roundness without using a visual chart. (c) 2005 Elsevier Ltd. All rights reserved.