Abstract: In order to increase the capacity of a large municipal waste landfill in south China,increasing the height of the dam is required. With the restricting from the existing building around the old dam,the extended part of the dam is designed as a steep gravel dam reinforced with geotextiles. Based on this special engineering,experimental tests were carried out to examine the effect of the erosion of leachate on the limiting tensional stiffness of geotextiles. The centrifuge test was carried out to examine the stability of the dam considering the special design. Subsequently numerical simulations were conducted to examine the stability analysis with considering several potential operating conditions,in which the influence of strength of geotextiles and water levels were quantified by the numerical analysis. Furthermore,the influence of the slope safety factor by varying the specific parameters of those influencing factors,were conducted. The results show that the strength of the geotextiles and the water level in the landfill have significant influence on the stability of the geotextile-reinforced earth dam. The strength of geotextiles plays a significant role for the stability of the dam,compared to that induced by the variation of water level. The calculation results show that the safety factor of the dam cannot meet the design demand when the strength of geotextile reduced to 0 percent of the design strength. However,the factor of safety of the dam can meet that requirements with at least 50% of the design strength for geotextiles.