Session Start Date

5-6-1984

Abstract

This paper presents the field behavior of a jetted sand drain installation at a preloaded wastewater treatment facility site in Gloucester, Massachusetts, U.S.A. The site is underlain by surficial estuary deposits above a stratum of stiff to soft clays. Detailed subsurface explorations and laboratory testing program provided data to predict amounts and rates of primary compression and rates of secondary compression in the referenced strata. The field behavior is compared to predictions through analyzed values of total settlement at the end of primary compression, coefficient of consolidation, and coefficient of secondary compression. A field instrumentation program allowed monitoring of settlements of individual strata and piezometric levels within the clay stratum. Delays in beginning construction allowed the preload to remain in place long enough to observe secondary compression of the strata, providing an unusual opportunity for long term collection of field data. Statistical curve fitting techniques were applied to the field settlement and piezometric data allowing the amount of total settlement at the end of primary compression and coefficients of consolidation and secondary compression to be backfigured independently of the laboratory data. The analysis technique, applied to settlements for the first time herein, is applicable to most installations having vertical drains. Analyzed results from field data are compared to predictions based on laboratory data. The results for this site indicate that conventional design methods tend to predict settlements that are slightly large for the clays and slightly small for the organics.

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

Performance of Sand Drains in a Tidal Marsh

This paper presents the field behavior of a jetted sand drain installation at a preloaded wastewater treatment facility site in Gloucester, Massachusetts, U.S.A. The site is underlain by surficial estuary deposits above a stratum of stiff to soft clays. Detailed subsurface explorations and laboratory testing program provided data to predict amounts and rates of primary compression and rates of secondary compression in the referenced strata. The field behavior is compared to predictions through analyzed values of total settlement at the end of primary compression, coefficient of consolidation, and coefficient of secondary compression. A field instrumentation program allowed monitoring of settlements of individual strata and piezometric levels within the clay stratum. Delays in beginning construction allowed the preload to remain in place long enough to observe secondary compression of the strata, providing an unusual opportunity for long term collection of field data. Statistical curve fitting techniques were applied to the field settlement and piezometric data allowing the amount of total settlement at the end of primary compression and coefficients of consolidation and secondary compression to be backfigured independently of the laboratory data. The analysis technique, applied to settlements for the first time herein, is applicable to most installations having vertical drains. Analyzed results from field data are compared to predictions based on laboratory data. The results for this site indicate that conventional design methods tend to predict settlements that are slightly large for the clays and slightly small for the organics.