Location

St. Louis, Missouri

Date

03 Jun 1993, 10:30 am - 12:30 pm

Abstract

Construction of a 21-foot wide, 28-foot deep braced excavation in Detroit soft clays has been completed. In order to protect an existing 50-year old tunnel adjacent to the excavation, a semi-rigid, tangent wall earth retention system was constructed to minimize the soil movements. The tangent wall was formed by 118 drilled piers with 42-inch in diameter and 41-foot long. The maximum soil lateral and vertical movements adjacent to the excavation were controlled below a magnitude of 2.0 inches, while bottom of the excavation experienced about 3 inches of heave. This paper presents the design considerations and construction performance of the retention system based on geotechnical instrumentation data. Prediction of maximum soil lateral movement based on a finite element analysis and a semi-empirical method conformed well with field measurements. Experience learned from the design and construction will be valuable for future construction of braced excavation systems in similar soil conditions.

Department(s)

Civil, Architectural and Environmental Engineering

Meeting Name

3rd Conference of the International Conference on Case Histories in Geotechnical Engineering

Publisher

University of Missouri--Rolla

Document Version

Final Version

Rights

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

Creative Commons Licensing

Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.

Document Type

Article - Conference proceedings

File Type

text

Language

English

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Jun 1st, 12:00 AM

Performance of a Semi-Rigid Braced Excavation in Soft Clay

St. Louis, Missouri

Construction of a 21-foot wide, 28-foot deep braced excavation in Detroit soft clays has been completed. In order to protect an existing 50-year old tunnel adjacent to the excavation, a semi-rigid, tangent wall earth retention system was constructed to minimize the soil movements. The tangent wall was formed by 118 drilled piers with 42-inch in diameter and 41-foot long. The maximum soil lateral and vertical movements adjacent to the excavation were controlled below a magnitude of 2.0 inches, while bottom of the excavation experienced about 3 inches of heave. This paper presents the design considerations and construction performance of the retention system based on geotechnical instrumentation data. Prediction of maximum soil lateral movement based on a finite element analysis and a semi-empirical method conformed well with field measurements. Experience learned from the design and construction will be valuable for future construction of braced excavation systems in similar soil conditions.