Model tests of geocell retaining structures

Model tests were performed on nine model geocell retaining walls to examine the effect of the geocells as a major material in retaining structures and the failure mechanism of the said structures under surcharge. The main variables in the tests include the height and the facing angle of the structure, the type of surcharge, and the reinforcement embedded in the two types of externally stabilized structures, i.e., gravity and facing types. Results showed that the deformation on the wall face and the backfill settlement both increased with increasing facing angle and surcharge. For the gravity type, the maximum lateral displacement occurs at the top of the wall and two failure modes can be observed, namely, interlayer sliding and overturning. For the facing type, due to its being lighter in weight, results show more displacement and settlement than the former type. In regard to the systems with reinforcements embedded in the backfill or the so-called hybrid systems, lateral displacement and settlement were both reduced significantly. Moreover, the reinforcing zone affects the deformed shape of the wall. When the reinforcement was embedded in the upper layers, the lateral displacement present was reduced significantly with the maximum value occurring at the mid-height of the wall. Conversely, for the case of reinforced lower layers, the maximum displacement occurred at the top.