Tran Duc Luot creator Bergado, Dennes T. Chairperson Ashford, Scott A. Examination Committee Sugimoto, M. Examination Committee The Government of Japan Scholarship Donor text th Bangkok Asian Institute of Technology 1996 monographic eng

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113 leaves The use of geotextiles is widespreaded for applications in construction of embankment over soft foundation in recent years. There are currently some uncertain assumptions in design method available for the selection of geotextiles as reinforcement or in evaluating the effect of this reinforcement upon the embankment behavior. In order to investigate the interface behavior between the backfill soil and the geotextile in geotextile reinforced embankment, laboratory experiments were carried out using large scale direct shear test apparatus. Weathered Bangkok clay and Ayuthaya sand were selected as subgrade and backfill soil, respectively. Two types of geotextile, namely: PEC-200 and TS-700, respectively referred as high strength and low strength geotextiles were used in this research. A total number of thirty one large scale direct shear tests were performed with different normal stresses and variour inclination of geotextiles. All of the results of large scale direct shear test followed the Mohr-Coulomb failure criteria ('t = C + cr0 tan ~ ). With the different inclination angles of geotextile to the shear plane, the maximum increase of shear force occurred at 40° and 41° for TS700 and PEC200, respectively. This relationship seemed to be independent to normal stress. The orientation of geotextile as reflected by the inclination factor, Ir, varied from 0.26 to 0.57 corresponding to initial inclination angle, 8, of 30° to 90°. The maximum value of Ir was 0.57 and was found at 8 of 90°. Thus, the maximum orientation of geotextile was only slightly greater than bisectional direction Cir= 0.5) and never reached to tangential direction. Finally, the limiting mobilized geotextile strain increased with increasing of confining stress and seemed to be not affected much by initial inclination angle. For nonwoven needle punched geotextile TS700, the limiting strain varied from 5% to 14%.For woven geotextile PEC200, strain of 3% to 5% were found at 30mm to 40mm of shear displacement, and then geotextile was slipped due to limitation in shear box dimension. Confirm inclination in test embankment, Ir of 0.25 to 0.50 agree with laboratory results, Ir not more than 0.57. A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering, School of Civil Engineering Thesis (M. Eng.) - Asian Institute of Technology, 1996 Geotextiles Asian Institute of Technology. http://203.159.5.9/ait-thesis/detail.php?q=B15150 http://203.159.5.9/ait-thesis/detail.php?q=B15150 20260818171003.0