Wabash and 10th Street

Wabash and 10th Street
Geotechnical Investigation and Engineering

Madrid CPWG was asked to complete soil borings and laboratory testing to support the Civil Engineering design for a proposed roadway re-alignment, widening, and roadway extension in Lakeland, Florida. Upon completion of borings for mast arm poles, a deep and thick deposit of organics was discovered indicative of a paleo-sinkhole. The design included fill heights on the order of 5 to 10 feet that likely would cause long-term differential settlement conditions that would be unacceptable for the new roadway.

Madrid CPWG Approach

Additional scope items were added to delineate the sinkhole feature and to design a stabilization program. Some SPT borings were completed in 1 foot of water in an area too soft to stand on without placing boards to spread the load; Madrid CPWG completed those SPT (Standard Penetration Test) borings with our ATV (All-Terrain Vehicle) rig shown to the right. The borings revealed that the sinkhole and organics covered a wide area including most of the intersection. Re-designing the intersection to avoid the sinkhole was not an option as not enough land was available. Madrid CPWG evaluated multiple stabilization options and designed a detailed surcharge program utilizing wick drains to compress the organic soil in a very quick manner. Madrid CPWG coordinated the plan with the Owner to ensure minimal disruption to local residents and school bus routes.

Madrid CPWG Benefit

Madrid CPWG designed a stabilization program that would only have the intersection closed for 1 to 2 months for the surcharge program in order to provide minimal disruption to the public. Surcharging programs without wick drains can often run for many months or even more than a year, which would not have been acceptable to the owner. Surcharging was also found to be the most cost-effective option compared to a pile-supported roadway, deep excavations and other mitigation techniques.