Journal Published Online: 14 April 2016
Volume 39, Issue 4

Direct Shear Testing of Clayey Sand Reinforced With Live Stake

CODEN: GTJODJ

Abstract

Large direct shear tests were conducted on compacted clayey sand, reinforced with Jatropha live stakes of various ages, under saturated and unsaturated conditions. The relationship between root cohesion and the side root area ratio appeared linear. For samples with stake stabilization but no fibrous roots, a stake installed in a larger drilled hole appeared to contribute lower strength increase and greater shear displacement than a stake in a smaller hole. All the unsaturated samples at a suction of approximately 23 kPa exhibited strain-hardening behavior. The rate of strength increase due to the root was affected by the soil's suction. The additional strength due to live stake and fibrous root could be reduced by a factor of 3.5 if the conditions change from unsaturated (at about 23 kPa suction) to fully saturated. A new model was proposed to account for the influence of suction on root cohesion considering the suction effects on bond stress, root tensile strength, root tensile modulus, and shear zone thickness.

Author Information

Jotisankasa, A.
Department of Civil Engineering, Kasetsart Univ., Bangkok, TH
Taworn, D.
Department of Civil Engineering, Kasetsart Univ., Bangkok, TH
Pages: 16
Price: $25.00
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Details
Stock #: GTJ20150217
ISSN: 0149-6115
DOI: 10.1520/GTJ20150217