A connection device for fastening two expanded cellular confinement structures includes an insertion member having insertion ends, an insertion member extension, an integral shank, and a handle member. A cellular confinement system includes first and second webs of cells made from strips bonded together in spaced apart areas. The strips form walls of the cells and at least some of the cells define open slots. At least one connection device fastens the first web and the second web together through the open slots. A method of fastening two expanded cellular confinement structures includes aligning two expanded cellular confinement structures; inserting an insertion member of a connection device through open slots; and turning the connection device.