Gabion Wall Reinforcement Using Micro Piles in a Soil Nailing Application

Wednesday, July 15th, 2015 by Elizabeth Cook

Challenge

A previously installed Gabion Wall was showing indication of instability and move-ment. Copper State Engineering was brought in to assess, and recommend a so-lution. An obvious location for the use of soil nails, with the added challenge of placing a “threaded” bar through 3’ of rock without damage to the threads. Ex-tremely limited access, and a precarious platform to work within, were additional complications.

Solution

Following a site visit by Arizona Foundation Solutions, it was determined our spe-cialty sized equipment, years of installations working in tight and precarious quar-ters safely, it was decided we could successfully accomplish the task.

Twelve strategically placed Con-Tech Systems, Titan Hollow Bar Micro Piles were installed horizontally to a depth of 20’. Saving the critical threads on the bars from damage while inserting through 3’ of rock, while maintaining a straight trajectory was accomplished by sheathing through PVC, and surgically directing the bar by hand.

The Micro Piles were then injected with grout, to their full depth and diameter.

A Micro Pile to be utilized as a Test Pile, had been installed and grouted three days prior. Specifications required a minimum 72 hour grout cure time prior to Pull Testing.

This Micro Pile was then “Pull Tested” in the specified sequence and duration for strength and proper installation, which indeed it passed to the satisfaction of all.

The entire wall was then sprayed with a 4” layer of Shotcrete.