PROBLEM TO BE SOLVED: To reduce irregularity in height of a track in a sleeper bearing- capacity reinforcing structure.
SOLUTION: The railway sleeper bearing-capacity reinforcing structure 10 is composed of normal sandbags 11, high-strength sandbags 12, sleepers 1 and ballasts 3. A plurality of the normal sandbags 11 are spread all over the whole surface of the excavated section 15 of a subgrade 4, and form a part of the subgrade 4. A plurality of the high-strength sandbags 12 are heaped up on the normal sandbags 11, and form a part of the ballast 3. The normal sandbag 11 and the high-strength sandbag 12 minimally constrain the movement of crushed stones on the insides, and the crushed stones on the insides intend to cubically expand in the case of the reception of train load, constraint stress is increased because the sandbags 11 and 12 receive constraint reaction by bags, and shear strength is augmented. Accordingly, even when the sleeper 1 repeatedly receives train load, the settlement of the sleeper 1 can be prevented. The irregularity in the height of the track is inhibited particularly at a smaller value by the subgrade biting preventive working of the normal sandbag 11 and the high-strength sandbag 12 installed into the subgrade 4.