Test Study On Stability Of Calcium Carbide Slag-treated Expansive Soil

Expansive soil is a kind of high swell-shrink soil, with strong moisture absorption. When the soil absorbs moisture will to be expansion to soften, after dehydrating the soil will be shrink and crack. With the result that, a large number of projects emerge crack, landslide, collapse accidents, etc in the later process of operation. So this study based on BaiSe a project of red mud embankment dam, to study the calcium carbide slag-treated expansive soil. For improved expansibility and stability research mainly include the following three aspects:(1) Expansion test:Through adding different quantity calcium carbide slag and using different time of stuffing soil to conduct the free expansive rate test. And preliminary evaluated the impact of the calcium carbide slag and time on soil improvement. Use the compaction instrument to make samples in following tests. According to the design demand, compaction degree is not less than97%of the swell-shrink total ratio test, to detailed conduct the results. The test results show that calcium carbide slag has good improved effects. With7%the calcium carbide slag mixed, study the effect of different water content and different dry density on swell-shrink total ratio.(2) The strength index study of the calcium carbide slag-treated expansive soil considerate two aspects including maintenance and wetting-drying cycle. By the use of the TSZ automatic triaxial apparatus for triaxial compression test to measure the strength of soil samples, Soil samples total cohesion and effective cohesion in the maintenance83days are linear growth. However, wetting-drying cycle has great influence on the soil strength, the first cycle drops most, from the third time will be more stability.(3) Through the matrix suction test to assess the influence of the calcium carbide slag on improving expansive soil. Use Van-Genuchten mathematical model to fit the soil water characteristic curve, with a very good correlation. It is obtained from the fitting parameters that the soil’s air intake value rise as the calcium carbide slag mixed increased, but when higher than7%, it does not change significantly.