Hostname: page-component-cd9895bd7-hc48f Total loading time: 0 Render date: 2024-12-22T22:16:02.802Z Has data issue: false hasContentIssue false

Geologic Control of Severe Expansive Clay Damage to a Subdivision in the Pierre Shale, Southwest Denver Metropolitan Area, Colorado

Published online by Cambridge University Press:  28 February 2024

J. D. Gill
Affiliation:
Michael W. West and Associates, P.O. Box 555, Morrison, CO 80465-0555
M. W. West
Affiliation:
Michael W. West and Associates, P.O. Box 555, Morrison, CO 80465-0555
D. C. Noe
Affiliation:
Colorado Geological Survey, Denver, CO
H. W. Olsen
Affiliation:
Colorado School of Mines, Golden, CO
D. K. McCarty
Affiliation:
Montana State University, Boseman, MT
Rights & Permissions [Opens in a new window]

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

Shortly after construction of a subdivision in the southwest Denver metropolitan area in 1986, a portion of the subdivision built directly on steeply-dipping strata of the Pierre Shale began experiencing damaging differential movements, causing house foundations to fail and pavements to warp and crack. This formation is a Late Cretaceous marine clay-shale composed predominantly of fluvial mixed-layer illite/smectite and quartz. During deposition of the shale, periodic and explosive volcanism generated thin beds of bentonite, consisting initially of volcanic ash and subsequently altered to nearly pure smectite. Some of these bentonite beds were exposed in a trench adjacent to the subdivision and perpendicular to the strike of the steeply-dipping strata. The thickest bentonite beds correlated well with linear heave features that these beds parallel the bedrock strike throughout the subdivision were mapped via severely deformed pavements. Mineralogical data show the bentonite bed that correlates with the worst damage within the subdivision consists of about 62% smectite by weight with mixed-layer illite/smectite expandability of 92%. By comparison, a sample of the typical silty claystone, which is fluvial mixed-layer illite/smectite mixed with detrital quartz from the adjacent strata, had about 23% smectite by weight with 70% to 90% illite/smectite expandability. Geotechnical tests for swell potential show that samples of 2 bentonite beds swelled 39% to 43% compared to 2% to 8% for samples of the typical silty claystone. It is proposed that differential swell resulting from stratigraphically-controlled differences in clay mineralogy and grain-size is the primary factor controlling extreme damage for this geologic setting.

Type
Research Article
Copyright
Copyright © 1996, The Clay Minerals Society

References

American Society for Testing and Materials. 1994. Moisture Content (D-2216), Atterberg limits (D-4318), Particle size distribution (D-422) and Swell (D-4546). In: Annual Book of Standards. Philadelphia, PA: ASTM. 4.08: 288307.Google Scholar
Busenberg, E. and Clemency, C.V.. 1973. Determination of the cation exchange capacity of clays and soils using an ammonia electrode. Clays & Clay Miner 21: 213217.CrossRefGoogle Scholar
Cobban, W.A., Merewether, E.A., Fouch, T.D. and Obradovich, J.D.. 1994. Some cretaceous shorelines in the western interior of the United States. In: Caputo, M.V., Peterson, J.A., Franczyk, K.J., editors. Mesozoic systems of the Rocky Mountain Region, USA. p 393413.Google Scholar
Cobban, W.A.. 1994. Personal communication. Regarding fossil identification, United States Geological Survey, Box 25046, Mail Stop 966, Denver, CO 80225.Google Scholar
Gill, J.R. and Cobban, W.A.. 1966. In: Kier, P.M., editor. New echinoid from the Cretaceous Pierre Shale of eastern Wyoming. The Red Bird section of the Upper Cretaceous Pierre Shale in Wyoming. U.S. Geological Survey Professional Paper 393-A. 73 p.Google Scholar
Gill, J.R. and Cobban, W.A.. 1973. Stratigraphy and geologic history of the Montana Group and equivalent rocks, Montana, Wyoming, and North and South Dakota. U.S. Geological Survey Professional Paper 776. 37 p.CrossRefGoogle Scholar
Lambe, T.W. and Whitman, R.V.. 1969. Soil mechanics. New York, NY: John Wiley & Sons. 553 p.Google Scholar
McCarty, D. and Eberl, D.. 1992. Written communication. Miner-alogical and Chemical analyses of samples.Google Scholar
Moore, D.M. and Reynolds, R.C.. 1989. X-ray diffraction and the identification and analysis of clay minerals. New York: Oxford University Press. 332 p.Google Scholar
Reynolds, R.C.. 1985. NEWMOD computer program for the calculation of the one-dimensional X-ray diffraction patterns of mixed-layer clays. Available from author, Dept. Earth Sciences, Dartmouth College, Hanover, New Hampshire, 03755.Google Scholar
Robinson, G.D., Klepper, M.R. and Obradovich, J.D.. 1968. Overlapping plutonism, volcanism, and tectonism in the Boulder batholith region, western Montana. In: Coats, R.R., Hay, R.L., Anderson, C.A., editors. Studies in volcanology—A memoir in honor of Howel Williams. Geological Society of America Memoir. 116: 557576.Google Scholar
Scott, G.R.. 1963a. Quaternary geology of the Kassler quadrangle, Colorado. U.S. Geological Survey Professional Paper 421-A. 70 p.CrossRefGoogle Scholar
Scott, G.R.. 1963b. Bedrock geology of the Kassler quadrangle, Colorado. U.S. Geological Survey Professional Paper 421-B. p 71125.Google Scholar
Scott, G.R. and Cobban, W.A.. 1965. Geologic and biostratigraphic map of the Pierre Shale between Jarre Creek and Loveland, Colorado. U.S. Geological Survey Miscellaneous Field Studies Map MF-482, scale 1: 62500, 2 sheets.Google Scholar
Schultz, L.G.. 1978. Mixed-Layer Clay in the Pierre Shale and Equivalent Rocks, Northern Great Plains Region. U.S. Geological Survey Professional Paper 1064-A. 27 p.CrossRefGoogle Scholar
Schultz, L.G., Tourtelot, H.A., Gill, J.R. and Boerngen, J.G.. 1980. Composition and Properties of the Pierre Shael and equivalent rocks, Northern Great Plains Region. U.S. Geological Survey Professional Paper 1064-B. B1–B114.Google Scholar
Thompson, R.W.. 1992. Performance of foundations on steeply dipping claystone. Proceedings of the 7th International Conference on Expansive Soils, August 3-5, 1992, Dallas, TX. 1: 438442.Google Scholar