Test Study on Soil-Water Characteristic Curve of Bentonite-Sand Mixtures

 

Li Pei-yong

PhD, Assoc. Prof., School of Civil and Safety Engineering, Dalian JiaoTong University, Dalian, China
e-mail: dlutlpy@yahoo.com.cn

Yang Qing

Professor, State Key Lab. of Coastal and Offshore Eng., Dalian Univ. of Technol.;Inst. of Geotech. Eng., School of Civil and Hydraul. Eng., Dalian Univ. of Technol., Dalian, China
e-mail: qyang@dlut.edu.cn

 

ABSTRACT

In this paper, test studies on soil-water characteristic curve (SWCC) of bentonite-sand mixtures are presented. Utilizing the pressure plate, the SWCCs are determined. Three states of mixtures are investigated, which are different initial dry density, different times of wetting-drying cycle and different proportions. The air-entry values and slope coefficients of straight-line section of SWCCs of mixtures are analyzed. Results show that for the bentonite-sand mixtures with different dry density, the logarithm of air-entry value increases linearly as dry density increases. The air-entry values increase linearly as the times of wetting-drying cycle increase. The slope coefficients of straight-line section of the SWCCs are similar, for mixtures with different times of wetting-drying cycle. It indicates that times of wetting-drying cycle have slight influence on drainage rate. For different proportions of mixtures, the air-entry values are influenced by relative packing ratio of pore. Greater packed density results in the greater air-entry values, which have phasic changes as mass percents of bentonite increase.

Keywords: Bentonite-sand mixture; Soil-water characteristic curve; Pressure-plate.

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