Model Tests for Two-Tier Slopes Supported with Ridge Walls of Geotextile Bags Under Lateral Loading

To explore the lateral bearing characteristics of two-tier slopes supported with ridge walls of geotextile bags, the model tests of two-tier slopes under non-uniform lateral loading were conducted in the conditions of four kinds of ridge walls supported with geotextile bags, including no support, inclined type supporting, L-shaped supporting and L-shaped supporting with notched sills, and three kinds of slope rates involving 1∶0.3, 1∶0.5 and 1∶0.75, respectively. The displacement of the slopes and earth pressure were analyzed under lateral loading. The results showed that the horizontal displacement of the second tier slopes was greater than those of the first tier slopes. Simultaneously, the earth pressure behind those walls increased with the wall height. And the earth pressure at the connections between the first and second tier slopes was the largest. Taking the non-supporting slope as reference, the horizontal displacement at the tops of the second tier slopes with inclined type, L-shaped and L-shaped supporting with notched sills decreased by 8.6%, 13.2% and 16.5%, respectively, and the earth pressure at the toes of slopes with inclined type supporting increased by 19.3%, and the earth pressure at the toes of the second tier slopes with L-shaped supporting increased by 32.6%. The earth pressure at the toes of the second tier slopes with L-shaped supporting with notched sills increased by 42.2%. Taking the slope at a slope rate of 1∶0.3 as reference, the heave height on crests of the second tier slopes at a slope rate of 1∶0.5 increased by 18.2%, the horizontal displacement of slope tops decreased by 7.1%, and the earth pressure at toes of slope increased by 7.8%. Simultaneously, the heave height on crests of the second tier slopes at a slope rate of 1∶0.75 increased by 34.8%, the horizontal displacement of slope tops decreased by 10.9%, the earth pressure at the toes of slopes increased by 23.1%. It showed that the failure of the second tier slopes preceded that of the first tier slopes. The lateral deformation resistance of the second tier slopes was maximum in support of geotextile-bag ridge walls with the L-shaped supporting with notch sills. In addition, the smaller the slope ratio was, the greater the capacity of the slope to resist lateral deformation was, the greater the capacity of the flexible ridge wall to resist lateral earth pressure was, and the larger the bearing capacity was.