Deep Soil Mixing (DSM) Columns to Improve Foundation Support for Bridge Approach Embankments

Bridge approach settlement is a common problem to the Transportation Departments nationwide. This uneven transition causes inconvenience to passengers and increases the cost of maintenance and repair of the distressed approach slabs. The Texas Department of Transportation spends millions of dollars annually to mitigate this problem across the state. The potential causes for this problem are numerous and purely site specific. Hence this problem may not have a unique solution. In an on-going research project, deep soil mixing (DSM) columns were utilized to stabilize soft subgrades and alleviate the bridge approach settlements. As a part of the assessment of DSM improvements, both embankment and foundation soils are extensively instrumented with inclinometers and extensometers to monitor for both lateral movements and settlements at different depths. Data collected from the instrumentation and a few laboratory experiments on the treated soil mixture were used to address the DSM treatment in stabilizing soft soils.