Triaxial Test Study on Swelling Properties of Bentonite-Sand Mixtures

 

Pei-yong Li

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

 

 ABSTRACT

In this paper, Utilizing GDS unsaturated triaxial apparatus, a study on swelling properties of bentonite-sand mixtures is carried out. A series of triaxial swelling tests is conducted on the mixtures with different intial dry densities. Based on the experimental data obtained, relationships between volumetric swelling strain and volumetric stress, volumetric swelling strain and water-absorbing volume, volumetric stress and water-absorbing volume are determined and analyzed. Then, a swelling constitutive equation of the mixtures is established, which reflects the influences of volumetric stress and water-absorbing volume on volumetric swelling strain at the same time. The results show that volumetric swelling strain increases as water-absorbing volume increases, but decreases as volumetric stress increases. Water-absorbing volume decreases as volumetric stress increases. For a given value of volumetric stress, water-absorbing volume has a maximum value at the end of swelling process.

Keywords: Bentonite-sand mixture; Triaxial swelling test; Swelling properties

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