Optical Characterization of Intrinsic Properties and Fabric of Coarse-Grained Soils

该研究项目旨在通过光学方法的发展，将包括颗粒形状、角度和表面粗糙度以及土壤结构在内的内在土壤特性引入更广泛的实践和研究中，从而快速量化它们，而不需要额外的时间或成本，而不是开发粒度分布。为了实现这一目标，沉积物成像（Sedimaging）系统将用于小于2毫米的颗粒，半透明分离表（TST）将用于较粗的部分。这两种系统在图像捕获之前都能快速地对具有统计代表性的土壤标本进行分类。最重要的是，虽然颗粒被分类，但它们彼此接触时不需要分离。这样就可以对大量的粒子进行快速评估。此外，由于最近推出了接近40 MPix的高分辨率相机，因此每次测试只需要一张高分辨率照片。主要研究任务包括：开发先进的沉积和TST系统；从三维组件图像中分割粒子，并选择分割后的粒子进行形状分析；分节颗粒的颗粒形状定量；沉积物成像和TST图像与传统（非原位）测量的颗粒圆度和球度的比较；样品内典型形状分布作为粒度函数的测定；确定确定形状描述符的最小粒径；用角点检测方法评价表面粗糙度基于小波的土壤组织势指数的建立进行实验室测试，以证实先前关于颗粒形状和织物效果的发现；并将该方法推广到视觉锥穿透仪现场采集的图像。更广泛的影响将在三个不同的方面得到解决。首先，沉降和TST测试将成为密歇根大学本科岩土工程入门课程的常规和独特的实验室练习。这将证明研究成果和发展确实转化为工程实践。其次，与密歇根大学人体工程学研究中心和三家当地砂和集料生产商合作，将对岩土工程实验室的工作环境进行评估，重点关注Sedimaging和TST系统所带来的改进，这些系统将工人从粒度和纵横比测试中解脱出来。最后，土工和土工环境工程技术转移（从研究到实践）的障碍将由土工专业领域（即土壤改良、深地基、挡土结构等）进行调查和记录。

This research project aims to bring intrinsic soil properties including particle shape, angularity and surface roughness as well as soil fabric into wider common practice and research through development of optical methods for rapidly quantifying them at no extra time or cost than required to develop grain size distributions. To accomplish this, a sediment imaging (Sedimaging) system will be used for particles smaller than 2 mm and a translucent segregation table (TST) will be used for the coarser fraction. Both systems rapidly sort a statistically representative soil specimen prior to image capture. Most importantly, although the particles are sorted, they need not be separated from contact with each other. This allows for a large number of particles to be rapidly evaluated. Furthermore, because of the recent introduction of high resolution cameras approaching 40 MPix, only one high resolution photograph is needed in each test. The major research tasks include: development of advanced Sedimaging and TST systems; segmentation of particles from images of 3D assemblies and selection of segmented particles for shape analysis; quantification of particle shape of segmented particles; comparison of particle Roundness and Sphericity obtained from Sedimaging and TST images with traditionally obtained (ex-situ) measures; determination of typical shape distributions as a function of particle size within specimens; establishing minimum particle size for which shape descriptors should be determined; evaluation of surface roughness by corner detection methods; development of a wavelet-based index for soil fabric potential; performance of laboratory tests for confirmation of previous findings on particle shape and fabric effects; and extension of methods to images collected in-situ by the vision cone penetrometer.Broader impacts will be addressed on three distinct fronts. First, the Sedimaging and TST tests will become regular and distinct laboratory exercises in the undergraduate Introductory Geotechnical Engineering course at the University of Michigan. This will demonstrate that research findings and developments do transfer into engineering practice. Secondly, working with the University of Michigan Ergonomics Research Center and three local sand and aggregate producers, the geotechnical laboratory work environment will be evaluated with emphasis on improvements created by the Sedimaging and TST systems that relieve workers from the tedium of particle size and aspect ratio testing. Finally, the impediments to technology transfer (from research to practice) in geotechnical and geoenvironmental engineering will be investigated and documented by geotechnical specialty area (i.e soil improvement, deep foundations, retaining structures, etc.).