The Influence Factors Study for Geogrid Pullout Test

The interaction coefficient of pullout (μ) between the interface of soil and geosynthetic is known the major parameter for designing the details of the reinforced soil. To obtain this coefficient (μ), it is suggested to perform the pullout test. Some researchers followed GRI or the like to guide the procedures for running this test. However, details of the test have not been clearly identified. In this study, factors that could affect the pullout resistance are subject to further evaluation. One type of thick HDPE, stiff geogrid was used with confinement of sand soil in the confining box. Factors focused in this study include the pullout rates, sleeve lengths, frictional effect of the box wall, and specimen widths. Findings indicated that the optimum pullout rate is 1.0 mm/min for fully mobilizing the pullout resistance and is used for the entire program. Sleeve length of 15 cm is ideal for eliminating the effect of the front wall of the box. With a specimen width of 20 cm, the boundary effect can be reduced to a minimum. Moreover, the results of pullout behavior as in the case of wall with low friction angle (3.7°) is not much different from that of wall with high friction angle (24.7°).