Numerical Study on the Settlement of Soft Soil Reinforced by Soil-Cement Columns comparing to Viet Nam standard - A Case Study in Can Tho, Vietnam

Tóm tắt

Soft clay in the Mekong Delta often settles too much under road embankments. This paper studies how the main geometric factors of soil–cement columns (SCCs)—column length and spacing—change the settlement. Forty-two 2D PLAXIS models were run for four lengths (8, 10, 12, 14 m) and nine spacing ratios (Sc/D = 2.0–4.0, column diameter 0.8 m). For the block ground reinforced by SCC, the calculated settlements were compared with Vietnamese standards TCVN 9403:2012 values and TCCS 41:2022. The results show three clear trends. First, short columns (8 m) give large settlement that grows quickly as spacing widens, while columns 12 m or longer make settlements almost constant for the same spacing range. Second, an economical spacing ratio of Sc/D is from 2.0 to 2.5. Third, the code method is inconsistent: it underestimates settlement for tight grids but overestimates it for long columns with wide grids. The study concludes that 12 m SCCs spaced at 2.0D –3.0D give deltaic clay the best balance between cost and performance. Wider grids or deeper columns should be checked with finite-element analysis to avoid unsafe or overly conservative designs.