Ecora was engaged by the British Columbia Ministry of Transportation and Infrastructure (MoTI) for an emergency response to develop temporary recommendations and short-term repairs of an embankment slope failure on Big White Road. The site is located on Big White Road approximately 6.5 km from the Highway 33 junction and 14 km east of Big White Ski Resort, BC.

In the summer of 2022, the only road leading to the resort experienced a failure in a steep embankment side slope and was in dire need of stabilization. The embankment failure occurred due to a combination of embankment toe erosion caused by the West Kettle River, groundwater seepage through the embankment at the embankment fill foundation interface, and sustained runoff over the embankment side slopes during a high precipitation event between June 13th and 14th, 2022 which triggered the embankment failure. The embankment failure resulted in a temporary single lane alternating traffic conditions being implemented on the impacted section of Big White Road.

The site location and conditions presented many unique challenges and considerable constraints that had to be considered by the design team. This included environmental concerns due to the proximity of the embankment to the West Kettle River, maintaining vehicle access on Big White Rd during construction, a high degree of variability in ground conditions which meant that any design solution had to accommodate unforeseen ground conditions, steep side slopes on either side of the existing embankment which excluded solutions that required the use of temporary excavations, significant seepage that was occurring at the embankment fill foundation interface needed to be addressed, increasing the shoulder width to accommodate CRB for vehicle safety and weather conditions became a limiting factor as the construction of the remedial works would extend into the fall which can see overnight temperatures plummet below zero degrees, which meant that the use of shotcrete in the remedial works was not a feasible.

The concept of a hybrid soil nail and mechanically stabilized earth (MSE) slope with a flexible permeable facing emerged as the favorable remedial solution. The concept of a hybrid soil nail and MSE slope with a flexible permeable facing emerged as the favorable remedial solution. The construction works commenced in the fall of 2022 and was completed in the early summer of 2023e.

The implemented remedial works were successful in stabilizing the embankment fill slope including addressing the seepage at the foundation interface and enabled the two lanes of traffic to be restored with sufficient shoulder width to enable concrete roadside barrier to be installed for vehicle safety.