The Influences of Vacuum–Surcharge Preloading on Pore Water Pressure and the Settlement of a Soft Foundation

Ming Lei, Shilin Luo (), Jin Chang, Rui Zhang, Xilong Kuang and Jianqing Jiang
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Ming Lei: College of Civil Engineering, Changsha University, Changsha 410022, China
Shilin Luo: College of Civil Engineering, Changsha University, Changsha 410022, China
Jin Chang: College of Civil Engineering, Changsha University, Changsha 410022, China
Rui Zhang: College of Civil Engineering, Changsha University, Changsha 410022, China
Xilong Kuang: College of Civil Engineering, Changsha University, Changsha 410022, China
Jianqing Jiang: College of Civil Engineering, Changsha University, Changsha 410022, China

Sustainability, 2023, vol. 15, issue 9, 1-15

Abstract: Vacuum–surcharge preloading is widely used in soft soil foundation reinforcement projects. To study the characteristics of the changes in pore water pressure and settlement of the soft soil foundation as a result of the effect of vacuum–surcharge preloading, in this paper, a consolidation model was established for large–sized sand–drain fluid–solid coupling along the depth direction while taking the sequence of the actual surcharge and vacuum into consideration by using FLAC 3D , and a soft foundation’s consolidation process was calculated and analyzed in detail. The results showed the following: (1) the sand drain could be used as a load boundary condition and a vacuum load could be realized by adjusting the pore pressure at the nodes. (2) For the effect of a single vacuum, the settlement and pore water pressure were evenly distributed on the horizontal plane, and the maximum calculated value of the surface settlement was 90.92 cm, but the phenomenon of a “pot–bottom shape” of the settlement and pore pressure gradually became obvious with the increase in the surcharge, and the maximum calculated value of the surface settlement was 153.01 cm. (3) In the numerical calculations, it was found that the pore pressure and settlement distinctly fluctuated once each level of surcharge was applied. The changes in the settlement were basically consistent with the measured values after the adjustment of positive and negative pressure, and the variation trend of the pore pressure was consistent with the measured value. (4) The depth affected by the vacuum could reach at least 16 m. All of these findings are expected to provide references for the calculation of consolidation in vacuum–surcharge preloading.

Keywords: soft foundation settlement; pore water pressure; numerical simulation of fluid–solid coupling; vacuum–surcharge preloading (search for similar items in EconPapers)
JEL-codes: O13 Q Q0 Q2 Q3 Q5 Q56 (search for similar items in EconPapers)
Date: 2023
References: View complete reference list from CitEc
Citations: View citations in EconPapers (1)

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