Numerical Simulation of Seismic Performance of Road Embankment Improved with Hybrid Type Steel Pile Reinforcement

Highway embankments are part of strategic infrastructures that play a critical role in connecting and transporting critical rescue components and disaster relief materials during natural disasters such as earthquakes, tsunamis, typhoons, and rainstorms. The failure of such structures during disasters can exacerbate the extent of damage to human lives due to delays in transporting rescue services. The 2017 NEXCO report points to a recent example of embankment damage in the town of Mashiki in the Kumamoto region as a result of the 2016 Kumamoto earthquake. Therefore, it is important to develop a sustainable and economical geotechnology applicable to existing and new highway embankments. This research proposes a new seismic mitigation technique that uses hybrid reinforcement to protect highway embankments and mitigate the associated ground subsidence. The technique aims to reduce lateral and vertical deformation of the embankment and the buildup of excess pore water pressure by reinforcing the underlying liquefiable soil with two types of steel piles deployed around and below the embankment foundation. The performance of the proposed technique is evaluated through a dynamic effective stress analysis using the LIQCA FEM program.