Boundary shear strength characteristic between surface soil and geosynthetic clay liner and its stability analysis in interface of irrigation pond

Geosynthetic clay liner (GCL) is an impervious liner for the construction of a dam body. It consists of bentonite encapsulated between woven and non-woven geotextiles, which are needle-punched. This method constructs a widening of an embankment to a precast embankment that was laid with a GCL. However, its detailed construction, the internal shear strength of the GCL, and the shear strength between the GCL and the dam body soil have not been reported. In this study, a direct box shear test was carried out to clarify the shear strength of bentonite, the boundary between the bentonite and geotextiles, and the boundary between the dam body soil and geotextiles. In this study, the dam body soil was decomposed granite soil. In addition, this study was carried out to evaluate the stability state of the dam body that employs a GCL. The main conclusions are as follows: 1) a bentonite that swelled uniformly and a bentonite laminated sealing sheet had almost the same shear strength; 2) the shear strength characteristic between soil and geotextiles varies by the type of soil or water content; and 3) the maximum safety factor is the boundary between the decomposed granite soil and GCL, and the minimum safety factor is the boundary between the bentonite and the geotextiles.