To solve the problem that ordinary gravity dam is easily damaged in large scale debris flows

a new debris flow blocking dam with spring support is proposed

and steel balls are used instead of large debris flow stones. This new type of debris flow dam was simulated under the impact of large debris flow stones by using finite element software Ansys /ls- dyna. The analysis of comparison between the new debris flow blocking dam and the ordinary gravity dam was made on deformation

reaction forces

the von Mises stress

acceleration and strain rate. The results show that compared with the ordinary gravity dam

the reaction forces of the new dam can be reduced to 1 /4

the impact acceleration of the ball can be reduced to 1 /3. 87

and the acceleration response of the dam can be reduced to 1 /2. 61. This research suggests the new style dam with spring support has a very good impact performance.