Experimental study on freezing and thawing deformation of geogrid-reinforced silty clay structure

Abstract

Reinforcement can reduce soil’s frost heave (F-H), but what kind of reinforcement condition is most beneficial to control soil’s F-H if it is not clear? In this study, orthogonal experiments of freezing and thawing (F-T) to reinforced silty clay under different conditions were carried out. F-H, thaw settlement (T-S) deformation and water content of three different heights of melting clay were tested. T-S displacement was positively correlated with water content and more closely related to upper layer clay’s water content. SPSS software was used to fit the regression equation of F-H and T-S displacement expressed by various influencing factors. The top three factors influencing the F-H and T-S displacement were initial water content, reinforcement spacing, and upper pressure. Taking the lowest displacement of F-H and T-S as control target, the optimal solution of all factors and target values were obtained with MATLAB software when the freezing temperature and number of freezing and thawing cycle (FTC) and upper pressure were − 15 °C, 5 times, and 30 kPa. The lowest values of F-H and T-S displacement were 3.61 mm and − 0.514 mm, respectively, when the values of the initial water content, compaction degree, and reinforcement spacing were 16%, 90%, and 25 cm, respectively.