Bahraich district (Uttar Pradesh, India) falls under seismic zone IV. The subsoil deposits in the Bahraich region consist of uniformly graded sand with a loose to medium-density profile and water tables vary at shallow depth. All these geological, compositional and state criteria lead to liquefaction during earthquakes. One particular ground improvement approach that lowers the risk of liquefaction and associated ground deformation is the installation of stone column in loose soil. Numerical analysis for implementation of stone columns in this region provides a better and efficient insight for the implementation of this technique to enhance ground condition and decrease the risk of liquefaction. In this study, (3D) finite element (FE) numerical analysis has been performed to simulate the stone column (SC). For 3D FE analysis an open-source computational platform OpenSeesPL is used. OpenSeesPL has a robust user interface that simplifies the effort-intensive pre and post processing phases. Initially, a liquefaction susceptibility analysis (LSA) was conducted, considering local geological, compositional, state, and historical criteria. The LSA indicates that the site under consideration is susceptible to liquefaction up to a significant depth (7.50 m), with a very high level of severity. Following that, a comparative analysis was performed between unimproved liquefiable soil and improved soil to demonstrate the impact of stone columns (SC) on the response of liquefiable soil to earthquake of 6.8 Mw. It was found that lateral displacement was reduced by 83.36% and excess pore pressure was reduced by 27.91%. The results of the present study were compared with other investigations, and it was found that the results are closely matching. Subsequently, a parametric study was also conducted to assess the influence of each factor such as area replacement ratio (Arr = 9%, 13%, 20%), diameter of stone column (D = 0.4 m, 0.8 m, 1.0 m, 1.2 m ) and stone column (SC) permeability (ksc = 0.01 m/s, 0.1 m/s, 1.0 m/s) on lateral surface displacement and excess pore pressure (EPP). The results show that increasing Arr, D, and k leads to reduction in lateral displacement and EPP. The maximum reduction in lateral displacement was 83.38%, 86.46% and 93.73% and maximum reduction in EPP was 10%, 26.65% and 94.43% respectively at Arr = 20%, D = 1.2 m and ksc = 1.0 m/sec. The outcomes of the study demonstrate that the installation of stone column is an effective measure for ground improvement and the mitigation of liquefaction in loose, saturated fine sand deposits.

Numerical Investigation of Liquefaction Behavior in Poorly Graded Fine Sand Reinforced by Stone Columns

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发表日期：

2025年12月18日

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Md Naseem Ahamad,
Neelu Patel,
V. P. Singh

摘要

Bahraich district (Uttar Pradesh, India) falls under seismic zone IV. The subsoil deposits in the Bahraich region consist of uniformly graded sand with a loose to medium-density profile and water tables vary at shallow depth. All these geological, compositional and state criteria lead to liquefaction during earthquakes. One particular ground improvement approach that lowers the risk of liquefaction and associated ground deformation is the installation of stone column in loose soil. Numerical analysis for implementation of stone columns in this region provides a better and efficient insight for the implementation of this technique to enhance ground condition and decrease the risk of liquefaction. In this study, (3D) finite element (FE) numerical analysis has been performed to simulate the stone column (SC). For 3D FE analysis an open-source computational platform OpenSeesPL is used. OpenSeesPL has a robust user interface that simplifies the effort-intensive pre and post processing phases. Initially, a liquefaction susceptibility analysis (LSA) was conducted, considering local geological, compositional, state, and historical criteria. The LSA indicates that the site under consideration is susceptible to liquefaction up to a significant depth (7.50 m), with a very high level of severity. Following that, a comparative analysis was performed between unimproved liquefiable soil and improved soil to demonstrate the impact of stone columns (SC) on the response of liquefiable soil to earthquake of 6.8 Mw. It was found that lateral displacement was reduced by 83.36% and excess pore pressure was reduced by 27.91%. The results of the present study were compared with other investigations, and it was found that the results are closely matching. Subsequently, a parametric study was also conducted to assess the influence of each factor such as area replacement ratio (A_rr = 9%, 13%, 20%), diameter of stone column (D = 0.4 m, 0.8 m, 1.0 m, 1.2 m ) and stone column (SC) permeability (k_sc = 0.01 m/s, 0.1 m/s, 1.0 m/s) on lateral surface displacement and excess pore pressure (EPP). The results show that increasing A_rr, D, and k leads to reduction in lateral displacement and EPP. The maximum reduction in lateral displacement was 83.38%, 86.46% and 93.73% and maximum reduction in EPP was 10%, 26.65% and 94.43% respectively at A_rr = 20%, D = 1.2 m and k_sc = 1.0 m/sec. The outcomes of the study demonstrate that the installation of stone column is an effective measure for ground improvement and the mitigation of liquefaction in loose, saturated fine sand deposits.