Wendy L Wieder

Using GRAIL Tools to remotely assess terrain conditions for austere entry

The Geospatial Remote Assessment for Ingress Locations (GRAIL) efforts under the Army Terrestrial-Environmental Modeling and Intelligence System (ARTEMIS) program have made significant advances in the remote assessment of terrain and soils for locating potential landing zone and drop zone (LZ and DZ) sites for military operations. The project identified sources of high-quality geospatial data, defined preprocessing requirements to produce global datasets for analysis, and created the GRAIL Tools software. The GRAIL Tools algorithms analyze and filter geospatial datasets to search for areas suitable for aircraft ground operations. GRAIL Tools then applies geometric criteria to determine if the required LZ/DZ will fit within the areas of suitable terrain and displays the potential LZs and DZs superimposed over geospatial imagery. Verification of the GRAIL Tools concept at Fort Hunter Liggett, California, developed and trained the suitability filter algorithms with regard to vegetation, obstructions, and soil strength. Further work served to enhance the algorithms and develop the full toolkit. Future work at a variety of sites, including work in northern regions with snow, ice, and freezing/thawing soils, will evolve the GRAIL Tools to handle the full spectrum of global terrain conditions for military operations. DISCLAIMER: The contents of this report are not to be used for advertising, publication, or promotional purposes. Citation of trade names does not constitute an official endorsement or approval of the use of such commercial products. All product names and trademarks cited are the property of their respective owners. The findings of this report are not to be construed as an official Department of the Army position unless so designated by other authorized documents. DESTROY THIS REPORT WHEN NO LONGER NEEDED. DO NOT RETURN IT TO THE ORIGINATOR. ERDC/CRREL TR-18-5 iii

Soil strength analysis of Sonoran Desert landforms

Connecting landforms to soil strength parameters can enable the prediction of soil bearing capacity and shear strength—important information for mobility and dust emission modeling. This project aimed to relate soil strength metrics to geomorphic landforms, focusing on five alluvial and aeolian landform classes in the Sonoran Desert. To achieve this, a variety of soil strength, dust emission, and soil texture measurements were made at 47 sites in California and Arizona; and these data were compared with landform classifications. Measurements of soil bearing capacity and shear strength varied significantly between landform classes. The aeolian landforms had significantly lower bearing capacity and shear strength than the alluvial landforms. The alluvial fan landform demonstrated consistently high soil strength, whereas the alluvial plain landform had relatively high mean soil strength but extreme site variability. The aeolian landforms were dominated by sand, whereas the alluvial landforms presented variable particle size distributions extending into loam and silt-loam classes. Silt and clay content were positively correlated with soil strength across all sites, while sand content was negatively correlated. Only the near-surface soil strength measures from the pocket penetrometer, Torvane, and vane shear correlated with dust emission flux and susceptibility. DISCLAIMER: The contents of this report are not to be used for advertising, publication, or promotional purposes. Citation of trade names does not constitute an official endorsement or approval of the use of such commercial products. All product names and trademarks cited are the property of their respective owners. The findings of this report are not to be construed as an official Department of the Army position unless so designated by other authorized documents. DESTROY THIS REPORT WHEN NO LONGER NEEDED. DO NOT RETURN IT TO THE ORIGINATOR. ERDC/CRREL TR-18-14 iii

Landing Zone and Drop Zone Criteria

Abstract : The criteria for landing zones (LZs) and drop zones (DZs), also known as austere entry surfaces, are extensive and varied. They range from very specific guidance on required geometry to more general guidance on required bearing strength of unprepared surfaces, such as soil or ice, and the smoothness of those surfaces. Current practice for siting LZs and DZs includes site surveys by trained personnel, often in hostile environments. Additionally, with the continued advancement of image analysis, it may be possible to identify potential LZ and DZ sites remotely and thus to reduce the need to expose personnel to dangerous conditions. This review intends to summarize existing Federal, Department of Defense, and other criteria for unsurfaced, unimproved LZs and DZs. The purpose of the summary is to consolidate criteria so that the criteria may be considered in the process of developing and refining methods to remotely locate and assess potential LZs and DZs by using satellite imagery.

Vegetation Impact on Soil Strength: A State of the Knowledge Review

Abstract : Researchers in a variety of fields have studied using vegetation to alter or reinforce soils. However, investigating the use of vegetation with regard to impacting soil strength and therefore improving vehicle trafficability and mobility, for both military operations and training purposes, is more limited. Much of the soil-reinforcement work reported in the literature deals with trees and larger shrubs appropriate for slope and bank stabilization. Other research efforts are for agricultural or forestry applications and involve crops and, again, large trees. While larger plant species would prohibit vehicle traffic and thus be inappropriate from the standpoint of vehicle mobility, the general observations and the different types of laboratory and field tests performed in these studies still provide valuable insight. This review discusses the issue of vegetation and its effect on a variety of soil-strength parameters. It also reviews work regarding the effect of vehicle operations on vegetation and conversely the effect of vegetation on vehicle performance, or trafficability. The intent is to provide a broad knowledge base of the variety of work done with vegetation and soils with particular attention to the applicability for vehicle mobility and land management goals.