MICS, Subsurface, Site selection, Stratigraphy, Water table, ColoradoMiddle Gust operationThe report documents the results of a site investigation conducted to support free-field ground shock calculations and field operations for Project MIDDLE GUST, Events I, II, and III. Complete boring logs, material classifications, and radiographic logs are presented that describe the subsurface materials at the site. The physiography, geologic history, stratigraphy, and lithology of the subsurface materials are also described. In addition to the usual material classification, index, and composition tests, an extensive series of stratic and dynamic, unconsolidated-undrained, uniaxial strain and triaxial compression tests, along with a miscellaneous series of direct shear tests, Brazil tensile tests, and conventional consolidation tests, were conducted on specimens obtained from undisturbed samples taken at the site.

IONThe report documents the results of a site investigation conducted to support a program of free-field ground shock calculations and field operations for Project MIDDLE GUST, Events 4 and 5. The site is characterized by a 28-ft-thick section of weathered clay shale overlying approximately 650 ft of competent clay shale of the Pierre Formation which overlies older sedimentary rocks. Complete boring logs, material classifications, and radiographic logs are presented that describe the subsurface materials at the site. The physiography, geologic history, stratigraphy, structure, and lithology of the subsurface materials are also described. In addition to the usual material classification, index, and composition tests, an extensive series of static and dynamic, unconsolidated-undrained, uniaxial strain and triaxial compression tests were conducted on specimens obtained from undisturbed samples taken at the site. (Author).

The report summarizes the results of material property investigations conducted for the MIDDLE GUST wet and dry test sites to support a program of preshot, two-dimensional, free-field ground shock calculations. Both sites are situated in the Pierre clay shale formation of Cretaceous age; however, the wet site is overlain by a 9-ft-thick water-bearing stratum of alluvium, while the dry site is essentially devoid of soil overburden materials. The geologic physiography, stratigraphy, structure, and lithology of the subsurface materials at each site are briefly described and compared herein. Details of the laboratory testing programs are reviewed, and an overview of the variations with depth of the dynamic compression and shear behavior of the materials at each site is presented. (Modified author abstract).