Location

St. Louis, Missouri

Session Start Date

6-1-1993

Abstract

An instrumented deep excavation in weathered rock adjacent to a deflection-sensitive historical building is described. Two permanent shoring systems were used, presenting an opportunity to measure and compare their behaviors. Adjacent to the historic structure, a tied-back drilled pier wall was used, while the remainder of the excavation was supported by a tied-back shotcrete wall constructed in top-down fashion. Instrumentation included inclinometers, tiltmeters, and tieback load cells, supplemented by optical surveys. Both support systems performed well, with movements within acceptable ranges. The maximum horizontal deflection of the drilled piers was 0.33 inch (8 mm), one-third to one-fifth that of the shotcrete. Settlements behind the drilled piers were significantly less than behind the shotcrete. Isolated minor cracking and widening of existing cracks occurred in the existing building. Tieback load cell data indicate that the source of movements can extend beyond the theoretical failure wedge.

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

Measured Behavior of a Deep Excavation in Weathered Rock

St. Louis, Missouri

An instrumented deep excavation in weathered rock adjacent to a deflection-sensitive historical building is described. Two permanent shoring systems were used, presenting an opportunity to measure and compare their behaviors. Adjacent to the historic structure, a tied-back drilled pier wall was used, while the remainder of the excavation was supported by a tied-back shotcrete wall constructed in top-down fashion. Instrumentation included inclinometers, tiltmeters, and tieback load cells, supplemented by optical surveys. Both support systems performed well, with movements within acceptable ranges. The maximum horizontal deflection of the drilled piers was 0.33 inch (8 mm), one-third to one-fifth that of the shotcrete. Settlements behind the drilled piers were significantly less than behind the shotcrete. Isolated minor cracking and widening of existing cracks occurred in the existing building. Tieback load cell data indicate that the source of movements can extend beyond the theoretical failure wedge.