Experimental Investigations on Behaviour of Strip Footing Placed on Chemically Stabilised Backfills and Flexible Retaining Walls

The gradual increase in population, as well as rapid development in the construction industry in recent years, has made it more urgent than ever to gain the sufficient knowledge and information needed to improve existing soil for geotechnical engineering purposes. This study focuses on the experimental investigations of small-scale physical model tests to evaluate the performance of selected locally manufactured non-traditional additives (SH-85 and TX-85) in field applications, particularly as the backfill of retaining walls. Unconfined compressive strength (UCS) tests, a set of physical model tests and a field emission scanning electron microscope (FESEM) were conducted. The physical models were different in terms of parameters such as the type of additive and the strip footing distance from the wall. The UCS test results showed that the addition of 9% (as the optimum amount) of both additives increased more than 80% of the compressive strength after 7-day curing periods. The results from the physical model tests showed that the ultimate capacity of the footing placed on the stabilised backfill soil increased greatly while the settlement reduced noticeably compared to the untreated backfill. Additionally, by increasing the distance of the strip footing from the wall, it increased the ultimate capacity of the footing. Besides that, the addition of additives in either powder or liquid form to the backfill led to a reduction in wall horizontal displacement and the strain distribution on the wall. Furthermore, less porous and denser soil fabric was observed on the surface of clay particles from FESEM images.