Location

Chicago, Illinois

Session Start Date

4-29-2013

Session End Date

5-4-2013

Abstract

Due to regulations requiring provision of car park in the typical multi-story buildings in the urban areas and the high cost of land, deep excavation adjacent to existing structures have become common-place in Iran. Limiting lateral as well as vertical displacement of the adjacent structures has proven to be a major geotechnical challenge especially in the coarse grained alluvium of Tehran where determination of geotechnical parameters is tedious. Often active temporary support methods such as "rigid pad – anchoring" and/or "anchored soldier piles" are used in combination with nailing. However, arriving at the optimum design for such projects for the sake of competitiveness in the typical "design-build" tenders is difficult due multiple choices as well as limited knowledge of geotechnical parameters. Hence accumulation data from case studies is deemed to be very useful. In this paper, details of a seventeen story building with 20m of excavation in the built-up region of Tehran are presented. The ground water level was initially found to be at the depth of 6m and it was required to lower the water table prior to excavation without any side effects. Rigorous monitoring and back analysis led to verification of geotechnical parameters as well as design model. The shortcomings of typical site investigations in case of coarse grained cemented soils as well as design procedures are outlined.

Department(s)

Civil, Architectural and Environmental Engineering

Appears In

International Conference on Case Histories in Geotechnical Engineering

Meeting Name

Seventh Conference

Publisher

Missouri University of Science and Technology

Publication Date

4-29-2013

Document Version

Final Version

Rights

© 2013 Missouri University of Science and Technology, All rights reserved.

Document Type

Article - Conference proceedings

File Type

text

Language

English

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Apr 29th, 12:00 AM May 4th, 12:00 AM

Deep Excavation in an Urban Area: A Case Study

Chicago, Illinois

Due to regulations requiring provision of car park in the typical multi-story buildings in the urban areas and the high cost of land, deep excavation adjacent to existing structures have become common-place in Iran. Limiting lateral as well as vertical displacement of the adjacent structures has proven to be a major geotechnical challenge especially in the coarse grained alluvium of Tehran where determination of geotechnical parameters is tedious. Often active temporary support methods such as "rigid pad – anchoring" and/or "anchored soldier piles" are used in combination with nailing. However, arriving at the optimum design for such projects for the sake of competitiveness in the typical "design-build" tenders is difficult due multiple choices as well as limited knowledge of geotechnical parameters. Hence accumulation data from case studies is deemed to be very useful. In this paper, details of a seventeen story building with 20m of excavation in the built-up region of Tehran are presented. The ground water level was initially found to be at the depth of 6m and it was required to lower the water table prior to excavation without any side effects. Rigorous monitoring and back analysis led to verification of geotechnical parameters as well as design model. The shortcomings of typical site investigations in case of coarse grained cemented soils as well as design procedures are outlined.