THE EFFECT OF MATRIC SUCTION ON THE SHEAR STRENGTH OF UNSATURATED SANDY CLAY

Authors

  • Heni Pujiastuti Department of Civil and Environmental Engineering, Universitas Gadjah Mada, Indonesia
  • Ahmad Rifa Department of Civil and Environmental Engineering, Universitas Gadjah Mada, Indonesia
  • Agus Darmawan Adi Department of Civil and Environmental Engineering, Universitas Gadjah Mada, Indonesia
  • Teuku Faisal Fathani Department of Civil and Environmental Engineering, Universitas Gadjah Mada, Indonesia 2Center for Disaster Mitigation and Technological Innovation (GAMA-InaTEK), Universitas Gadjah Mada, Indonesia

Keywords:

Soil Water Characteristic Curve (SWCC), filter paper method, triaxial test, degree of saturation

Abstract

The shear strength parameters of the soil is the key engineering property required for the design
of geotechnical structures and stability analysis. The shear strength of an unsaturated soil is controlled by matric
suction. This research examined the effect of matric suction on the shear strength behavior of sandy clay using
a series of experimental tests in the laboratory. The contact filter paper method was used to measure matric
suction and the SoilVision knowledge-based system was used to give an approximation of the entire soil water
characteristic curve (SWCC). The shear strength of the unsaturated sandy clay was examined using a series of
unconsolidated undrained (UU) triaxial tests to identify the relationship between shear strength, cohesion,
internal friction angle, and matric suction. The result shows that the shear strength of the soil increases as
matric suction increases. It was found that when the matric suction is smaller than air entry value (AEV), the
shear strength of the soil increases as matric suction increases and the increment is linear because the soil is in
saturated conditions. At a certain matric suction value (on soil samples occurred at 40-600 kPa matric suction
values), there is a significant increase in the shear strength of soil associated with the inter-particle force
produced due to negative pore water pressure. Furthermore, at a high matric suction, the relationship between
shear strength and matric suction tend to be stable as in a low water content, the matric suction is not transmitted
effectively to the contact point of soil particles.

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Published

2018-02-27

How to Cite

Heni Pujiastuti, Ahmad Rifa, Agus Darmawan Adi, & Teuku Faisal Fathani. (2018). THE EFFECT OF MATRIC SUCTION ON THE SHEAR STRENGTH OF UNSATURATED SANDY CLAY. GEOMATE Journal, 14(42), 112–119. Retrieved from https://geomatejournal.com/geomate/article/view/782