Experimental Study On The Long-Term Stability Lime-Ash Stabilized Expansive Soil Embankment

The thesis studies, which dealing with the representative expansive soil in Baise city, Guangxi. Through the indoor environment simulation test, the mechanism tests and analysis of slope stability, the study examines the effects of environmental factors on the long-term stability of the lime stabilized expansive soil embankment, which based on the distribution and the transmission of the soil temperature and humidity field and applies the mechanism.In order to ensure the strength and stability of embankment's filling, some technical indicators, such as degree of compaction, the best ratio of mixes the lime-ash, sealing lime-ash time, soil water content of filling, are determined through mechanism tests. Based on the environmental temperature,humidity,rainfall and sunlight simulation test, the soil body inner temperature and the humidity data are measured, and the soil surface cracks and the displacement are observed. The model test results show that environment temperature and humidity changes have a little impact on soil surface cracks' development, the displacement of soil, soil strength. After the Sunshine and rain's cycling, the widest crack reaches the width of about 5 mm, the depth of 3-4 cm, the largest displacement of 7.1 mm. Rainfall sunshine wetting and drying cycles have more effect on soil cracks and displacement than the impact of the environment temperature and humidity to the cycle.The three-axis strength test of the indoor wetting and drying cycle comes to the results that the strength of the lime stabilized expansive soil decreases with the increase of soil water content and the number of wetting and drying cycle, cohesion have a certain linear relation with the number of cycle. In addition, the number of inner friction angle varies a little, and has a horizontal linear relation with wetting and drying cycles. Based on the results of the environmental simulation and the mechanism tests, analyzing the stability of the lime stabilized expansive soil embankment slope through the module Geo-Slope of GeoStudio software, that changes of climate affect the stability of the slope great is obtained. With the temperature, humidity, sunlight, rainfall and other environmental factors of climate change rapidly, slope stability correspondingly and intensively decreases. On the other hand, compared to other environmental factors, its stability decreased more when the slope is soaked after the wet and dry cycle. Stability of lime stabilized expansive soil embankment slope is related to the height of that. That is to say that, under the same conditions the bigger the height of that, the smaller the factor of stability.