Rock Bolting for Slope Stabilization
In November of 2005, a large rock slide occurred along Interstate 90 on the eastern side of Snoqualmie Pass. The slide forced the closure of I-90 until an assessment had been completed and a rock fall fence was installed. Washington Department of Transportation (WSDOT) appointed Wilder Construction to initiate site cleanup and stabilization, which needed to be completed as quickly as possible to minimize restrictions during the high volume traffic of Thanksgiving weekend.
Wilder Construction Company
Wyllie & Norrish Rock Engineers Inc.
Crux Subsurface Inc.
Crux was contracted to provide emergency rock bolting to stabilize additional potential rockslides at the same location. Prior to Crux’s arrival, several rock bolts were installed that did not reach the required depths for embedment, nor did they achieve the required pull out strengths. In addition to grouting as opposed to using epoxy, Crux employed a specialty drilling approach to achieve project requirements.
Exposure of continued rock fall necessitated that installation equipment be craned into place using work platforms. Cranes were set up outside the rockslide area to avoid potential injuries and damage. During the course of drilling, a large rock slab broke free and severed a platform anchor, exhibiting the severity of the problem and confirming the need for deeper rock bolts. Initial rock bolts were installed to secure the outer limits of the rockslide and allow cranes to move within closer proximity for the remainder of the project.
Crux crews worked through the Thanksgiving holiday in challenging winter weather to ensure the timely reopening of I-90’s east bound lane. The project was successfully completed in a timely manner.