Alternative Title

Paper No. 7.25

Location

St. Louis, Missouri

Session Start Date

3-8-1998

Session End Date

3-15-1998

Abstract

Excavation support is commonly provided using soil-nailed walls or tie-hack walls. This paper describes two case histories where nails and anchors where installed using a hollow reinforcing bar and a disposable drill bit. A lean grout was pumped through the reinforcing bar as it was driven into the ground. This process created a reinforced grout column with a diameter of about 150 mm. This procedure reduced the time of installation and resulted in cost savings of about 25% in comparison with conventional procedures. The procedure was used successfully to install nails in sandy gravels and silty sands. It was also used successfully to install tic-back anchors and the measured horizontal and vertical movements behind the wall were well within acceptable limits. Pull-out tests indicated that the ultimate pull-out resistance of the nails/anchors was between 58.3 to 65.6 kN/m (4 to 4.5 kips/ft) in the gravelly sands and 49.6 kN/m to 56.8 kN/m (3.4 to 3.9 kips/ft) in the silly sand (30%) tines. The soil-nail approach was not found to be practical where thick sequences of clean sands were encountered due to surface raveling and caving.

Department(s)

Civil, Architectural and Environmental Engineering

Appears In

International Conference on Case Histories in Geotechnical Engineering

Meeting Name

Fourth Conference

Publisher

University of Missouri--Rolla

Publication Date

3-8-1998

Document Version

Final Version

Rights

© 1998 University of Missouri--Rolla, All rights reserved.

Document Type

Article - Conference proceedings

File Type

text

Language

English

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Soil-nailed and the Tie-back Wall Construction Using Hollow Nails

St. Louis, Missouri

Excavation support is commonly provided using soil-nailed walls or tie-hack walls. This paper describes two case histories where nails and anchors where installed using a hollow reinforcing bar and a disposable drill bit. A lean grout was pumped through the reinforcing bar as it was driven into the ground. This process created a reinforced grout column with a diameter of about 150 mm. This procedure reduced the time of installation and resulted in cost savings of about 25% in comparison with conventional procedures. The procedure was used successfully to install nails in sandy gravels and silty sands. It was also used successfully to install tic-back anchors and the measured horizontal and vertical movements behind the wall were well within acceptable limits. Pull-out tests indicated that the ultimate pull-out resistance of the nails/anchors was between 58.3 to 65.6 kN/m (4 to 4.5 kips/ft) in the gravelly sands and 49.6 kN/m to 56.8 kN/m (3.4 to 3.9 kips/ft) in the silly sand (30%) tines. The soil-nail approach was not found to be practical where thick sequences of clean sands were encountered due to surface raveling and caving.