WorldWide Drilling Resource

Adapted from Information Provided by CRUX Subsurface and ADOT In the early morning hours of February 20, 2013, a landslide ripped through U.S. 89 near Page, Arizona, causing over 150 feet of roadway to buckle, leading to an indefinite closure of the highway. As a re- sult of the landslide, pavement was torn in six-foot-high sections. The Arizona Department of Transportation (ADOT) paved Navajo Route 20 as an interim so- lution to the closure as they worked to de- termine the location and severity of the slide. Crux Subsurface provided emergency core drilling and instrumentation services on the project. Drilling was performed to determine the landslide’s exact location, see if it was still moving, and establish the general stability of the slope. Seventeen core holes, ranging in depth from 29 to 250 feet, were drilled for a combined total of 1793 feet. The damaged roadway created unique access challenges requiring a combination of track-mounted drill rigs, as well as helicopter support. Though subsurface conditions were tricky; core recovery was successfully completed through formations including the Chinle, which primari ly consists of fluvial mudstone, si ltstone, and sandstone. Optical/acoustical downhole imaging was provided in three bor ings, and incl inometers were installed in seven borings. In addition to subsurface con- ditions and access constraints, another major project challenge was successfully drilling and installing inclinometers in an active landslide. On c e i n v e s t i g a t i v e drilling was complete, a full envi ronmental clearance (wh i ch was r equ i r ed t o secure federal funding) was granted so repair work could begin. The repair involved moving the existing roadway approximately 60 feet away from the landslide area. Nearly one million cubic yards of material were blasted and removed to make way for the new road. ADOT recently completed the extensive repairs required on U.S. 89, and has since reopened the highway for traffic. Photos courtesy of ADOT &% ! "" * "(%$ ))) (" $( ' & $ %# # " (" $( $ ( " !" !! ! &% ! % ! (" $( & $ $ $ " ! $ $ ! ! $ ! $ # $ $ $ US 89 Repairs Completed - Roadway Reopened WorldWide Drilling Resource ® 18 DECEMBER 2015