Long Term Performance of Recycled Plastic Pins in Increasing the Base Resistance of MSE Wall Base

Mechanically stabilized earth (MSE) walls underlain by weak soil are prone to base sliding failure which causes the structure to fail in the long run. Recycled plastic pins (RPP) can be a viable and sustainable solution for increasing the base resistance of MSE wall. The objective of the present study is to evaluate the long-term performance of MSE walls reinforced with RPPs at the base. A field-scale study was conducted by constructing four identical MSE walls in Irving, Texas-three of the sections were reinforced with 3.05 m long RPPs having different combinations of cross-sections and spacings, whereas the other section was left unreinforced. All the sections were identically backfilled with a soil height of 1.5 m initially. The sections were instrumented with vertical inclinometer casings along with pressure plates to monitor the displacement and pressure variance at the wall base, respectively. After more than three years of monitoring, the field data indicated that the unreinforced section failed after only six weeks from construction while the reinforced sections are still in a stable condition with minimal displacement. In addition, 66%-76% reduction of lateral earth pressure was observed against the face of the wall in the reinforced sections in comparison with the unreinforced section. The RPPs acted as a shear key to restrain the base sliding of the wall. Based on the study it can be summarized that RPPs can be used as a long-term solution for increasing the base resistance of MSE wall.