| Soil Water Characteristic Curve, which reflects the relation between Suction and Soil water content, is an important tool of description of unsaturated soil. Filter paper method is a convenient, fast and practical way in the study of the SWCC and therefore the calibration curve of the filter paper directly affects the SWCC. Modified measurement methods were put forward to mend the imperfections of the existing filter paper suction rate curve rate methods. Based on modified methods, a series of experimental studies of unsaturated high liquid limit red clay soil water characteristic curve have been launched.Main achievements are concluded as follows:(1) Based on axis-translation technique, conducting studies for the high liquid limit red clay potential suction with the GEO—Experts, a unsaturated high liquid limit red clay matrix suction- moisture curve has been obtained. Test results, which was gained by improving the moisture content of measurement methods, show that the drying method is more accurate determination for soil water content.(2) According to the measured test data of SWCC, the modified SWCC model was valuated with synthetically considering the fitting precision. The modified Van Genuchten model was proposed by ignoring the influence of the residual water content parameters. Calculations indicate that the modified Van Genuchten is a suitable SWCC model for describing unsaturated high liquid limit red clay with water features.(3) The calibration method of the existing filter paper suction rate curve was improved. Based upon the filter paper suction rate curve gained from the improved calibration method, the matrix suction of unsaturated high liquid limit red clay was measured by using the filter-paper method; Then proceeding to conduct variance error calculation in standard of SWCC obtained by the pressure plate extractor. After analyzing and comparing, determing the feasibility of improved filter paper suction calibration curves. |
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