Bag material and crushed stone placement method using bag material

A bag material that has a cylindrical shape and that can be folded back at an intermediate position in a longitudinal direction, wherein

• crushed stones can be stored in a folded part of the bag material, and
• an opening on one side of the bag material can be moved to a position close to an opening on the other side of the bag material, the bag material comprising:
• a one-side closing rope that is provided near the opening on the one side of the bag material and that closes the opening on the one side of the bag material;
• and
• an other-side closing rope that is provided near the opening on the other side of the bag material and that closes the opening on the other side of the bag material, wherein
• the one-side closing rope and the other-side closing rope are configured to operate as lifting ropes that, when engaged by at least one hook to lift the bag material, cause the opening on the one side and the opening on the other side to close, and
• a release of one of the one-side closing rope or the other-side closing rope causes the opening on the one side of the bag material or the opening on the other side of the bag material to open.

A crushed stone placement bag, comprising:

• a unitary bag material having a first end and a second end opposite the first end, the unitary bag material being tubular with a first opening at the first end and a second opening at the second end;
• a first rope at the first end of the unitary bag material;
• and
• a second rope at the second end of the unitary bag material;
• wherein
• in a state in which an intermediate portion of the unitary bag material between the first end and the second end is folded back toward one of the first end or the second end, a pocket is formed within a folded back portion of the unitary bag material,
• the unitary bag material is configured to accommodate crushed stones in the pocket within the folded back portion of the unitary bag material,
• the first rope and the second rope are configured to operate as lifting ropes that, when engaged to lift the unitary bag material with crushed stones in the pocket within the folded back portion of the unitary bag material, cause the first opening on the first end and the second opening on the second end to close, and
• releasing one of the first rope or the second rope causes the first opening on the first end of the unitary bag material or the second opening on the second end of the unitary bag material to open with the other of the first rope or the second rope remaining engaged such that the other of the first opening or the second opening remains closed so as to release the crushed stones from the pocket within the folded back portion of the unitary bag material.