Static and dynamic behavior of hunchbacked gravity quay walls

One of the parameters that can affect the lateral pressures behind a retaining wall is the back-face shape of the wall, which can be controlled by the designer, and has not been investigated experimentally. Therefore, in order to study this behavior, a set of 1g shaking table tests was carried out on hunched back gravity type quay walls made of concrete blocks. Crushed stone and silica sand were used in the backfill and subsoil, respectively. The subsoil was prepared by moist tamping. The models were fully instrumented and beside each earth pressure transducer a pore water pressure sensor was also installed behind the wall therefore the lateral effective stress acting on the wall could be calculated. Tests were performed with various base accelerations on models with different subsoil relative densities. The results show that the earth pressure increases at upper portions of the wall and decreases by the leaning slope at lower elevations. Depending on the back-face shape of the wall the total thrust and overturning moment would be increased or decreased after an earthquake. However, the hunched back-shape of the wall tends to raise the point of application of the total thrust exerted on the wall. Other advantages of hunched back walls are demonstrated as well.