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The FieldSed is an inexpensive portable device for performing an image-based soil particle size analysis. The process, which includes the image analysis, is referred to as SedImaging (short for sediment imaging). The FieldSed was used for an investigation of Kalamazoo River sediments to generate over 100 particle size distributions (PSDs). Core samples taken from the river were tested in a nearby field lab. When necessary, samples were processed prior to testing in the FieldSed to remove particles greater than 2.0 mm and those finer than 0.075 mm. Doing so was necessary to ensure the efficiency of the current SedImaging method. A small number of specimens was selected for quality control testing to determine the reproducibility of SedImaging results. This testing also involved sieve analyses in ascertaining the agreement between SedImaging and sieving results. The control test results presented in this paper demonstrate that the FieldSed is a promising device that can rapidly, accurately, and repeatedly determine particle size distributions in field labs for geotechnical and geoenvironmental application 

SedImaging is an innovative alternative particle size analysis method developed to obtain high-resolution particle size distributions (PSDs) of sands. It was developed at the University of Michigan (UM) and is based on wet processing and digital image analyses of fine to medium sands. This work summarizes a variant of the SedImaging method, named FieldSed, which was first applied in a field lab setting for a sediments site by the authors and colleagues in October 2017. The goal of this work was to detect subtle variations in the fine sand and fines compositions as a pilot test at a field laboratory, without use of a sieve set or oven drying. The testing program included replicates, independent testing by UM, and other quality control measures. Sediment processing included wet-removal of fines and particles larger than coarse sand; preparation of the sample in a pre-sorter tube followed by sedimentation in a tall, water-filled column to sort the sands; and the collection and analysis of high-resolution digital imagery of the settled sand. The FieldSed method included variations to estimate mass percentages of oversized (> 2 millimeters [mm]) and undersized (< 0.075 mm) sediments, and throughput improvement. Wet sieving and air drying were used to separate and prepare oversized sediments for weighing. Multiple decants of sediment-water mixtures were used to wash out more dispersive fines. Decanted fines contents were estimated by differences in wet weights and by specific gravity approximations. Digital images were analyzed and used to generate highresolution PSDs, which typically included more than 80 size bins from 2 mm to less than 0.050 mm. The FieldSed method was successful in clearly distinguishing coarse and fine material, as well as defining the gradient between medium sands, fine sands, and coarse silts. Color, angularity, and other grain characteristics from the digital imagery were noted. With further testing to improve processing rates and efficiencies, the method could be applied to provide same-day field decisions. More efficient and faster processing could be achieved for characterization of cleaner sands, and applications could be expanded further, such as to assess suitability of post-dredge sand cover materials in the field. 

The vision cone penetrometer (VisCPT) fits a traditional cone penetrometer (CPT) with a camera to obtain continuous in situ soil images. A previously developed image analysis method determines several textural indices for each captured image. The textural index profiles can identify thin soil layers and lenses that may be undetected by the CPT. A newly redesigned VisCPT having a much higher resolution camera than in previous VisCPTs has been developed. The larger resolution expands the range of soil sizes that can be optically characterized by the system. Updated hardware and image analysis techniques will enhance the capabilities of the VisCPT for generating accurate soil profiles. 

A previously-developed SedImaging test quickly determines the particle size distribution (PSD) of coarse-grained soils. The test involves photographing and analyzing a soil following sedimentation through water to sort its particles by size. Generating a PSD by SedImaging takes a fraction of the time required by traditional sieving. Due to its large size and weight, the original SedImaging device is suitable only for laboratory settings. Therefore, a new FieldSed system has been designed as a field-adaptable version of the original SedImaging system. While it utilizes the same Harr wavelet image analysis methods as the original SedImaging test, FieldSed uses smaller-scale, lightweight hardware to make it practical for use in any testing environment. FieldSed also enables many parallel tests to be performed, thus greatly reducing testing time. The FieldSed-produced PSDs match sieving results very well.