Abstract: In order to solve the problem that ordinary gravity debris flow retaining dam is easy to be damaged by large rocks in debris flow disaster, and to make full use of the advantages of good plasticity and impact resistance of H-shaped steel, a new type of debris flow retaining dam with built-in H-shaped steel is proposed. The finite element ABAQUS software is used to carry out the numerical simulation under the impact of the block stone. The dynamic response of the dam is compared with that of the ordinary gravity debris flow retaining dam in terms of the dam bottom reaction force, top displacement, acceleration, energy absorption, etc. The results show that the reaction force of the new type of dam with built-in H-shaped steel is about 1/2 less than that of the ordinary dam, and the top displacement of the new type of dam is 9/13 of that of the ordinary dam. Concrete and H-steel form double retaining effect. After concrete crack, H-steel still has better bearing capacity and deformation capacity. The new type of dam with H-shaped steel improves the anti impact performance of the ordinary gravity debris flow retaining dam and weakens the disaster of debris flow block rock impact.

Key words: built-in H-shaped steel debris flow retaining Dam, the Impact of block stone, dynamic response, impact resistance