Shallow slump stabilization using percusion soil nails at Hamelin creek site on Highway 725:02, Peace Region, AB

摘要

A precast concrete arch culvert was constructed to pass Hamelin Creek under the 24 m high embankment of Highway 725:02 in Northern Alberta. During construction in 2003, several slides occurred on the marginally stable valley slopes. Extensive mitigation works were constructed to stabilize the site, however deep seated slope creep movements continue on the northwest quadrant of the highway embankment subjecting the culvert structure to distress. Rapid downcutting of the streambed upstream of the culvert following construction has also resulted in shallow slumps along the toe of the northwest slope. There was concern that these slumps could retrogress and further destabilize the large deep seated slide. It was therefore necessary to improve the stability of these shallow slumps along the toe of the slope. The method chosen consisted of using "soil nails" to reinforce of the slide mass. The soil nails consisted of 6 m long by 38 mm diameter hollow steel bars that were installed using a percussion and rotary hammer that drove the nails in a 1 m by 1 m pattern. The paper describes the percussion soil nail installation technique and provides details about the installation equipment. The results of soil nail pullout tests and an assessment of the stability improvement is also provided.