Effects of Backfill Soil on Excessive Movement of MSE wall

The use of mechanically stabilized earth (MSE) retaining wall has gained popularity as an alternative of conventional cast in place concrete walls. The construction of mechanically stabilized earth wall is cost effective, requires less site preparation and technically more feasible compared to conventional concrete retaining wall. However, use of backfill with high fine content and their poor drainage behavior can cause excessive wall movement or even failure. The current paper presents the case study of a MSE wall located at state highway 342 of Lancaster, Texas. The top of the MSE wall has moved as much as 300 mm to 450 mm (12 inches to 18 inches) only five years after construction. An extensive site and laboratory investigation testing program was conducted to determine the possible causes of MSE wall movement. The site investigation included soil test boring and resistivity Imaging (RI). Laboratory testing of the collected soil samples were conducted to determine the characteristics of backfill soil. Based on the test results, it was determined that the presence of high fine content may have caused the excessive movement of the MSE wall. The movement of the MSE wall was also modeled using finite element program PLAXIS, and inclinometer were installed to monitor any additional movement of MSE wall.