| The geological environment of the mountains area is complex in southwest China where is widely covered by mixed soil, one of the mixed soil is colluvial mixed soil which covers the mountain area in west Sichuan. Under natural conditions, the colluvium mixed soil is non-saturated and its mechanical properties change significantly as the surrounding water environment changing. Natural slopes in the mountain area in west Sichuan are mostly covered by this kind of mixed soil. As a result, the soil moisture content is changing due to groundwater and rainfall etc., which often contribute to deformation or landslide. Based on the unsaturated soil mechanics theory, combining the soil-water characteristic test and unsaturated consolidation test, consolidation characteristics and its influences of the mixed soil was studied in this thesis. The main contents and conclusions are as follows:1. Routine physical tests NO.3mixed soil sample(from Dadu river) were carried out, the content of the tests include natural water content, original density, grading curve, grain composition analysis, mineral composition identification of the mixed soil. Comparing with the routine physical tests of NO.1, NO.2mixed soil (from Dujiangyan) which done by predecessors, comparative analysis was conducted. Significant difference of their physical form among three mixed soils was found.2. Pressure plate instrument was employed to measure soil-water characteristic curve of the mixed soil samples under three different initial void ratio (e0=0.7,0.9,1.1). The experiment found that matrix suction and soil moisture content is inversely related if the initial void ratio of the identical mixed soil is the same; the larger the void ratio is, the smaller the soil moisture content if matrix suction is the same.3. Unsaturated oedometer was employed in consolation test of mixed soils under different initial void ratio and different matrix suction conditions. The results are:smash-resistance of the soil sample increases as the matrix suction increasing if the initial void ratio of the identical mixed soil sample is the same and smash-resistance of the soil sample increases as the void ratio decreasing if the matrix suction is the same:significant difference was found in deformation when the initial conditions of different mixed soils is same. The results of the tests support that the consolidation characteristics of unsaturated mixed soils is connected with matrix suction, initial void ratio, mineral composition, shape and its content, sand content etc. |
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