关键词: 岩土工程, 高填方边坡, 稳定性研究, 碎块石土, 直剪试验, 有限元强度折减法, 滞水层

Abstract: The stability of high fill slope which filled with sand-shale gravelly soil was studied based on a practical case of an airport high fill slope in southwest China. Rock and soil mass shear strength indexes were obtained through large direct shear strength tests in the field of the test section. At the same time, the deformation instability mechanism was simulated by strength reduction FEM. The result indicates that the silty clay layer is the weak interlayer of high fill slope foundation, and it will significantly reduce the stability of the high fill slope without treatment. Along with the fine grain material of sand-shale gravelly soil infiltration, the aquitard is formed with certain thickness between filling-up soil and stable basement, and the shear strength of this layer is obviously lower than the filling-up soil. The distribution of the aquitard on slippery surface can be changed by setting steps in basement excavation. The range of slope slippery surface through the aquitard decreases with the increase of steps height, and the slope stability coefficient increases. Possibility of slope global instability can be reduced by selecting appropriate slope shape.

Key words: geotechnical engineering, high fill slope, stability study, gravelly soil, direct shear strength test, strength reduction FEM, aquitard