Effect of static and dynamic loadings on unsaturated soil slope stability

The objective of This study is to find the effect of dynamic loads on slope stability. The parameters studied in this research are horizontal displacement of vibration, frequency, suction values and the form of slope failure. A laboratory model was manufactured in the form of a box with dimensions of (2000 X 1000 X 1450) mm that slides on a rail installed on the ground and moved by a dynamically generated system. To explain the effect of dynamic load. three dynamic tests were performed. The one direction horizontal vibration displacement of the first, second and third tests are (10, 20 and 40) mm respectively. Dynamic conditions were applied as a horizontal vibration at frequencies of (0.5, 1.0 and 2.0) Hz. The time duration for each frequency value is (3) minutes. The acceleration during vibrations was measured during the test with an accelerometer that was placed inside the soil and on the shaking table. The main results showed that the dynamic load was negatively affected in its slope bearing capacity. It decreased from (408) kPa at the static test to (382.6, 306, 280.6 kPa) at the three dynamic tests, respectively. On the other hand, the measured amount of initial negative pore water pressure (suction) of the layers (upper, middle and lower) was found to be (25, 23, and 21) kPa respectively. Results also showed that the suction values were slightly changed during the tests. The experimental results were compared with that obtained from numerical simulation using Geo Studio software. Experimental results are nearly identical to that obtained from numerical analyses.