Location

St. Louis, Missouri

Session Start Date

6-1-1993

Abstract

A new Combined Sewage Overflow (CSO) basin was constructed in Saginaw, Michigan. The project required an 8.5 foot (2.6 m) diameter connecting sewer to be constructed under a 12 foot (3.7 m) high stockpile of spoil from the excavation for basin. The soil profile at the site contained a 32 foot (9 .8 m) thick layer of compressible organic silt. Since the weight of the stockpile was anticipated to cause settlement of the sewer, a surcharge was placed to preconsolidate the organic silt prior to construction of the sewer. Analysis indicated prefabricated vertical (PV) drains would be required to achieve the desired consolidation within a period of about 3 months. PV drains were installed under the 12 foot (3.7 m) high stockpile with an additional 12 foot (3.7 m) high surcharge. Remote settlement gauges and piezometers were installed to monitor the surcharge. Actual measured settlements of the surcharge indicated the required consolidation occurred approximately 3 times faster than anticipated.

Department(s)

Civil, Architectural and Environmental Engineering

Appears In

International Conference on Case Histories in Geotechnical Engineering

Meeting Name

Third Conference

Publisher

University of Missouri--Rolla

Publication Date

6-1-1993

Document Version

Final Version

Rights

© 1993 University of Missouri--Rolla, All rights reserved.

Document Type

Article - Conference proceedings

File Type

text

Language

English

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Jun 1st, 12:00 AM

Surcharging of Organic Silt Using Prefabricated Vertical Drains

St. Louis, Missouri

A new Combined Sewage Overflow (CSO) basin was constructed in Saginaw, Michigan. The project required an 8.5 foot (2.6 m) diameter connecting sewer to be constructed under a 12 foot (3.7 m) high stockpile of spoil from the excavation for basin. The soil profile at the site contained a 32 foot (9 .8 m) thick layer of compressible organic silt. Since the weight of the stockpile was anticipated to cause settlement of the sewer, a surcharge was placed to preconsolidate the organic silt prior to construction of the sewer. Analysis indicated prefabricated vertical (PV) drains would be required to achieve the desired consolidation within a period of about 3 months. PV drains were installed under the 12 foot (3.7 m) high stockpile with an additional 12 foot (3.7 m) high surcharge. Remote settlement gauges and piezometers were installed to monitor the surcharge. Actual measured settlements of the surcharge indicated the required consolidation occurred approximately 3 times faster than anticipated.