Session Start Date

5-6-1984

Abstract

A desiccated crust of overconsolidated soil commonly forms at the surface of compressible soil deposits. If a depression of the groundwater level occurs, the desiccation zone penetrates into the soil profile. At sites where the groundwater level has subsequently risen, a net overconsolidation will exist in the soil profile below the crust. Settlements of structures may be affected by the overconsolidation and by the ability of the desiccated layer to distribute surface stresses over the lightly overconsolidated soil below the crust. This paper presents the use of profiles of laboratory test results and observation of color changes within the soil profile as independent methods to evaluate the thickness of the desiccated crust and the amount of overconsolidation below the crust. The settlements of steel grain storage tanks founded upon alluvium exhibiting desiccation profiles at two sites in Western Iowa are presented. The net overconsolidation stress was estimated from the yield point of the load-settlement curve using elastic stress distribution methods. Estimates of the stress history of the project sites obtained through settlement observations are compared with estimates based on profiles of laboratory tests and color changes within the profile.

Department(s)

Civil, Architectural and Environmental Engineering

Appears In

International Conference on Case Histories in Geotechnical Engineering

Meeting Name

First Conference

Publisher

University of Missouri--Rolla

Publication Date

5-6-1984

Document Version

Final Version

Rights

© 1984 University of Missouri--Rolla, All rights reserved.

Document Type

Article - Conference proceedings

File Type

text

Language

English

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May 6th, 12:00 AM

Settlement of Three Grain Tanks on Alluvial Soils Exhibiting Desiccation Profiles

A desiccated crust of overconsolidated soil commonly forms at the surface of compressible soil deposits. If a depression of the groundwater level occurs, the desiccation zone penetrates into the soil profile. At sites where the groundwater level has subsequently risen, a net overconsolidation will exist in the soil profile below the crust. Settlements of structures may be affected by the overconsolidation and by the ability of the desiccated layer to distribute surface stresses over the lightly overconsolidated soil below the crust. This paper presents the use of profiles of laboratory test results and observation of color changes within the soil profile as independent methods to evaluate the thickness of the desiccated crust and the amount of overconsolidation below the crust. The settlements of steel grain storage tanks founded upon alluvium exhibiting desiccation profiles at two sites in Western Iowa are presented. The net overconsolidation stress was estimated from the yield point of the load-settlement curve using elastic stress distribution methods. Estimates of the stress history of the project sites obtained through settlement observations are compared with estimates based on profiles of laboratory tests and color changes within the profile.