Three-Dimensional Finite Element Analysis of Shankumugham Beach Road Due to Rainfall-Induced Storm Surge

Over the past few years, heavy rainfall-induced storm surge has resulted in coastal erosion and consequent beach loss in Kerala. Shankumugham beach road in the Thiruvananthapuram district is one such road that was earlier protected by a gabion wall along the seashore. During the 2019/2020 monsoon period, the gabion walls and half lane of the road got washed away due to rainfall-induced storm surge. Due to heavy rainfall, the tidal height increased by 21% which led to the erosion of beach soil, including the foundation soil of the gabion wall. To reclaim the beach road, remedial measures in the form of a diaphragm wall with rubble mound and soil anchor were designed and constructed. In the present study, a three-dimensional finite element modeling (FEM) of the diaphragm wall and armor layer was performed considering the dynamic effects of wave action. In addition, a comparative study was done between the 2D limit equilibrium method (LEM) analysis result and the 2D and 3D FEM output under static and dynamic loading conditions. The results from the study verify the stability of the structure in the existing condition.