To increase the rigidity by creating a dilatancy due to shear deformation to the waste tire thereby forming a stress-strain type non-linear loop in a cylindrical laminated body and thus a subgrade making method by waste tires filled with particulate matter capable of forming hard pile-shaped improved bodies and of adaptively following up any deformation in the subgrade in addition to the creation of the subgrade.

The subgrade making method and the subgrade developed by this method can provide an expansive cylindrical laminated body 10 which creats dilatancy after cramming granular particulate matter 5 to the cylindrical laminated body 1 of the waste tire 2; this is placed in a soil stabilization area and the subgrade to be developed is constituted by adopting Geo-textile and using other features such as tire chips and tire shreds, forming a shrinkage allowance for the granular particulate matter compressed and filled up on the upper end portion of the expansive cylindrical laminated body in addition to other features such as pre-filling of the granular particulate matter in the gaps created between recessed and projected portions of the waste tires before lamination and the mixing of water-expansive polymers with the granular particulate matters.