Ứng xử cố kết của đất sét lòng sông khi gia cường đệm cát và vải địa kỹ thuật dưới điều kiện nén 3 trục

Abstract

A clay excavated from a river bed was used to replace sand as backfill soil for rural roads, bringing many benefits and drawbacks. Methods of using a geotextile and sand cushion were applied to improve the soil consolidation process and increase its capacity. The results showed that the soil consolidation process occurred faster up to 3 times when reinforced by the sand cushion and about 1,6 times with geotextile reinforcement under triaxial compression test without side expansion. These numbers were 4 times and 1,7 times in one-dimensional consolidation, respectively. Additionally, the times of primary consolidation in the triaxial compression test without side expansion were lower from 10 % to approximately 30 %  compared to those in one-dimensional consolidation in the same conditions. This situation happened due to side friction between the soil and the ring when the soil height was high. The research also introduced a new method to investigate the coefficient of earth pressure (K_o) in the triaxial compression test without side expansion to determine the effective horizontal stress from the effective vertical stress.