Rapid Shear Response of a Needle-Punched GCL

摘要

This paper presents rapid internal shear strength data for a needle-punched geosynthetic clay liner (GCL) that wasrnobtained using a large direct shear device. A series of monotonic (i.e., single direction) shear tests illustrate the effectrnof shear displacement rate R on material response at four normal stress levels. The data indicate that peak shearrnstrengths first increased and then decreased as R was increased from 0.1 to 28,000 mm/min. The highest peakrnstrengths occurred at R = 100 to 10,000 mm/min and were 13 to 23% higher than corresponding static peak strengths (Rrn= 0.1 mm/min). Static peak strengths were found to be generally conservative at each normal stress level.rnDisplacements at peak shear strength consistently decreased with increasing R and increasing normal stress. Residualrnshear strengths increased markedly with increasing R for R ≥ 1 mm/min, whereas the reverse trend was observed for Rrn< 1 mm/min.