PROBLEM TO BE SOLVED: To provide a pressure wave damping structure for a fixed construction which damps pressure waves generated when a mobile body rushes into an entrance of the fixed construction and pressure waves generated when the mobile body recedes from the entrance.
SOLUTION: The partition wall 5 of the fixed construction is a vertical wall separating railways 2a, 2b from each other. The partition wall 5 is set such that a midpoint of a distance L between the partition wall and each of side walls 3c, 3d almost corresponds to the center O1 or O2 of the railway 2a or 2b, and therefore a cross sectional form of a tunnel 3 is almost bilaterally symmetrical with respect to a train 1. As a result, when the train 1 moving along the railway 2a in a direction A rushes into a portal 3a, rush waves W5 radiated in a direction C are damped compared with the case that the partition wall 5 is not arranged in the tunnel 3. In the same manner when the train 1 moving along the railway 2b in a direction B recedes from the portal 3a, receding waves W6 radiated in a direction D are damped compared with the case that the partition wall 5 is not arranged in the tunnel 3.