Physical modeling of the trench with rigid retaining walls reinforced with inclined relief shelves

Connecting relief shelves (RS) to the retaining walls play a significant role in reducing the lateral pressure of the earth on the retaining wall of the trenches. So far, the conducted research has only evaluated the vertical state of the RS. In this article, physical modeling has been used to investigate the role of inclined RS in reducing static and active lateral pressure on the retaining wall in order to improve the stability of trenches. In this regard, by making a system including a rectangular cube box in the laboratory and performing several series of 1g tests, the changes of lateral pressure on the retaining wall during the couple of inclined RS with overheads have been evaluated. It was found that the effect of an upward-sloping RS (70 degrees) with an increase in the amount of overhead and RS width in reducing the lateral pressure on the wall was greater than that of a vertical (90 degrees) and downward sloping RS (110 degrees). This result, which was proved for the first time in the current study, shows that the changes in the angle of the RS perpendicular to the wall, either upwards or downwards, have a positive effect on reducing the lateral pressure on the wall by creating dispersion in the force level and anchor concentration. Its role will be insignificant when the width of the RS is small.