Experimental Study on Dynamic Elastic Modulus of Unsaturated Silty Clay

 

Meng Wang

School of Civil and Hydraulic Engineering, Dalian University of Technology, Dalian, China
Tuner_meng@163.com

Qing Yang

School of Civil and Hydraulic Engineering and The State Key Lab. of Coastal and Offshore Engineering, Dalian University of Technology, Dalian, China
Qyang@dlut.edu.cn

Mao-tian Luan

School of Civil and Hydraulic Engineering and The State Key Lab. of Coastal and Offshore Engineering, Dalian University of Technology, Dalian, China

ABSTRACT

In order to simulate dynamic behavior of unsaturated soils under transient or cyclic loading induced by earthquake shaking or traffic loads through controlling matrix suction, the second development of the static and dynamic universal triaxial and torsional shear apparatus which had been designed by Dalian University of Technology in China associated with Seiken in Tokyo of Japan was carried out. The improved apparatus can reproduce complex stress conditions and stress paths and also can be used to perform various experimental tests of unsaturated soils with different dry density and different controlled suction under complex consolidation conditions, which is more extensively applicable than the original apparatus. Using improved apparatus, dynamic triaxial tests for unsaturated slity clay with different matric suctions were performed under 100,200 and 300kPa consolidation pressures. The maximum dynamic Elastic Modulus Edmax and the curves of Ed e and the curve of Edmax e were obtained and analyzed comparatively. It was shown that the improved static and dynamic universal triaxial and torsional shear apparatus for unsaturated soils can be perfectly used to study dynamic behavior of unsaturated soils by net confining stress (s3 ua) and matric suction (ua uw) controlling, and the maximum dynamic triaxial modulus Edmax with lower controlling matrix suction was less than that with higher controlling matrix suction under same consolidation pressures, and the maximum dynamic triaxial modulus Edmax under higher consolidation pressure was more than that under lower consolidation pressure when matrix suction was same, and the curve of Ed e was not almost influenced by net confining stress (s3 ua) and matrix suction (ua uw).

Keywords: Dynamic elastic modulus, Matric suction, Unsaturated, Dynamic triaxial, Silty soil

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