OasisLMS

The combination of local geological, compositional, state, and historical factors in the Bahraich region, classified under Zone IV seismicity, along with the shallow water table near the ground surface, renders the area vulnerable to liquefaction phenomena during intense ground motion. The subsoil deposits in the Bahraich region consist of uniformly graded sand with a loose to medium-density profile, and the presence of a certain percentage of fine particles leads to liquefaction during earthquakes. Installation of a stone column in loose soil is one of the robotic ground enhancement techniques that reduces the risk of liquefaction and related ground deformation. Numerical analysis for the implementation of stone columns in this region revealed the high efficiency of this technique for enhancing ground condition and decreasing the risk of liquefaction. For the numerical study, the three-dimensional FE simulations were performed using the open-source computational platform OpenSeesPL, which has a robust user interface that simplifies the effort-intensive pre- and post-processing phases. Initially, a liquefaction susceptibility analysis (LSA) was conducted, taking into account local geological, compositional, state, and historical criteria. Following that, a comparative analysis was performed between unimproved liquefiable soil and improved soil to demonstrate the impact of stone columns on the response of liquefiable soil. Subsequently, a parametric study was conducted to assess the influence of each factor (area ratio, diameter, and permeability of the SC) on lateral surface displacement at the center, excess pore pressure at the center, as well as at the edge of the finite element model. The LSA indicates that the site under consideration is susceptible to liquefaction at a significant depth, with a high level of severity. The results of the finite element analysis demonstrate that the installation of gravel drains (SC) is an effective measure for ground improvement and the mitigation of liquefaction in loose, saturated fine sand deposits.

Keywords: Soil liquefaction; Ground Enhancement; Stone column; Loose sand; Finite element analysis; Excess pore pressure; OpenseesPL.

MD Naseem Ahamad, Motilal Nehru National Institute of Technology Allahabad, Prayagraj; Neelu Patel, Motilal Nehru National Institute of Technology Allahabad, Prayagraj; Vishwajeet Pratap Singh, Motilal Nehru National Institute of Technology Allahabad, Prayagraj

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