3/5/2013 11:13:00 AM ADOT engineers conduct geotechnical analysis at site of US 89 landslide
Before the Arizona Department of Transportation (ADOT) can move forward with a design to repair the damaged section of US 89 south of Page, the agency needs to determine whether the mountain slope has stabilized after the Feb. 20 landslide. That's where the work of the geotechnical engineers comes into play.
Last week, after ADOT received environmental clearance, geotechnical engineers began drilling shafts to insert equipment called inclinometers into the earth. These plastic pipes will measure slope movement at a specific location.
"This week we know we had an event with a landslide and it's not a typical landslide," said Steve Boschen, ADOT deputy state engineer of design. "It's a deep-seated bedrock-type slip. We are looking at somewhere between 100 and 150 feet and that's why we had 10 inclinometers installed right now."
In addition to inclinometers, ADOT is using several other tools to learn what is happening underneath the foundation of US 89. ADOT is using extensometers above the ground to measure changes in tension from the bottom of the slope to the top with a pulley device that has a 30-pound weight registered to a scale.
ADOT is also using a three-dimensional laser scanner, called LiDAR, to map the landslide from the ground, while the agency created an aerial digital terrain by flying above the ground.
US 89 will remain closed for the immediate future. There is no timetable to reopen the highway, which has approximately 500 feet of damage, including 150 feet of pavement that settled four to six feet because of the landslide and failure of the slope.
More information on ADOT's geotechnical analysis is available at adotblog.blogspot.com.