Bi-Modulus Columns / Vertical Drains
Canadian Pacific Rail (CP) was planning to make track alignments in its Sapperton Yard located in the Westminster Subdivision of Coquitlam, British Columbia. In order to provide the necessary bearing capacity, control settlements, and meet the design criteria of this project, ground improvement was recommended to improve the current site condition between Mile 3.2 and 5.25 of the mainline.
The soil profile detected consisted generally of the following:
- Fill: consisted of gravelly sand with a trace of fines to a depth of 1.5m;
- Peat: consisted of fibrous peat to clayey organic silt to a depth of 2.5m;
- Silty Clay / Clayey Silt: silty clay to clayey silt to a depth of 13.5m;
- Silty Sand / Sandy Silt / Silt Clay: extend to refusal depth at 24.5m.
It was recommended by the Engineer to install Vertical Drains and preload the area that needs treatment. Due to the potential effect on nearby tracks and project time constraints, Menard Canada offered to design and construct Bi-Modulus Column (BMC) as an alternate solution to Vertical Drains and preload/surcharge to safely support the realignment of the track on the areas that needed ground improvement.