Laboratory and numerical modeling of strip footing on geotextile-reinforced sand with cement-treated interface

This paper presents the results of a laboratory and numerical study on the effects of cement treatment of the interface between geotextile and sand on the bearing capacity of a foundation built on geotextile-reinforced sand. The bearing capacity of a 25 cm × 7.5 cm strip footing on a 90 cm × 25 cm × 30 cm sand box reinforced using a single-layer reinforcement of different lengths including, 20, 30, 45, 60, 75 and 90 cm, was studied in a laboratory. A cement-treated zone was created on the geotextile to improve the friction and adhesion of the interface zone. Tests were also conducted on reinforced soil without a cement-treated zone and the results were compared. A finite element model was calibrated and used for further studies. The results of the laboratory tests indicated that cement treatment of the interface between the geotextile and sand increases the bearing capacity of the foundation by 6%-17%, depending on the length of the reinforcement. The effectiveness of the cement-treated interface on improving of the bearing capacity is more evident with shorter-length reinforcements. For a certain bearing capacity, the required length of the reinforcement was reduced by approximately 40% when the interface zone of the sand and reinforcement was cement-treated. The effect of the cement-treated zone on the bearing capacity was more evident in low settlement levels, and decreased as the length of the reinforcement increased.