Evaluating the Seismic Bearing Capacity of Strip Foundation Adjacent to Geogrid-Reinforced Slopes Using Finite Element Limit Analysis Method

Building construction on slopes is inevitable, despite many limitations. Due to the seismicity of Iran, calculating the seismic bearing capacity of foundations is more important. The construction along a slope has been observed to result in a reduction in the bearing capacity. To mitigate this decrease, various improvement techniques, such as soil reinforcements like geogrids, can be employed to partially offset this reduction. The present study investigates the impact of ground slope (10 and 20 degrees) on the bearing capacity of granular soils with varying internal friction angles (25, 30, 35, 40, and 45 degrees) in both seismic and static conditions. This investigation employs the finite element limit analysis method and OptumG2 software to determine the upper and lower bounds of the bearing capacity. The findings indicate that the implementation of kh=0.1 leads to a reduction in the seismic bearing capacity of the foundation, ranging from 2 to 12 percent. The effective length of the geogrid is contingent upon the internal friction angle of the soil and varies within the range of 2B to 3B. Additionally, the study revealed that the optimal distance between the footing and the slope edge (X/B) is influenced by the internal friction angle, with a significantly bigger impact than the slope angle. The optimal distance (X) was estimated to lie within 2B to 4B for internal friction angles of 25, 30, and 35 degrees. Conversely, for internal friction angles of 40 and 45 degrees, the X value was assessed to be no less than 5B.