Variation of Moisture Content and Safety Factor of Silt Subgrade under Rainfall Infiltration

Abstract

Because of the special capillary and water-sensitive characters, the moisture content of silt subgrade in Alluvial Plain of the Yellow River is generally higher than the optimum value, which will lead to bad support conditions of subgrade. In order to analyze the water-absorbent property of silt subgrade, both the rainfall seepage and the capillary phenomenon were simulated in laboratory, which reveals that both factors have distinct effects on the moisture content of compacted silt soil. Triaxial tests of compacted silt soil reveal that the cohesive force reduces obviously with the increasing of moisture content. What’s more, the internal friction angle also reduces rapidly arriving at saturation state. By adopting Geo-slope code, the rainfall infiltration mode of silt subgrade was simulated under different rain type and rain duration. Results show that the subgrade slope is easy to lose stability because of much rainfall infiltration. In addition, the minimum safety coefficient happens at the time of rainfall ending. And the slope safety can be threatened seriously by the repetitious rainfall.

Mechanical Properties, Curing Mechanism, and Microscopic Experimental Study of Polypropylene Fiber Coordinated Fly Ash Modified Cement–Silty Soil

“…Silty soil is formed by the long-term weathering of rocks, and its particles are mainly powder and sand particles, so the particles are poorly cohesive and have a loose texture, with low strength, poor grading, and strong capillary action [ 1 , 2 , 3 ]. In the eastern Henan Province of China, due to it is location in the middle and lower reaches of the Yellow River, the rivers in the territory constantly impact on the coastal areas, gradually forming a wide alluvial plain, and there are a large number of layered silty soils in the area.…”

Numerical Study of Subgrade Humidity Field Evolution under Different Rainfall Infiltration Affected by Initial Water Contents

“…Therefore, under same rainfall condition, the evolution of the subgrade humidity field from its initial state, is expected to be further studied. Zhang and Song (2011) studied the dynamic change of the water content with the increase of the infiltration time under the same water head and the same initial water content in a one-dimensional infiltration experiment. Mahmood and Kim (2011) investigated the reliability of the unsaturated subgrade under rainfall infiltration by measuring the distribution of the matric suction of the slope cross section in a period of time under different rainfall intensity.…”