The research seminar of 973 project on “Mechanisms and Risk Analysis of Extremely Large Mountain Torrents and Debris Flows in Western China” was held in Chengdu on Mar. 6th, 2011. It was the first group meeting for the Research Topic No.2 (“Soil-water coupling effect and mechanisms of large debris flows”) and attracted over 20 participants, including the researchers from IMHE (CAS), Wuhan University, Sichuan University, and Southwest Jiaotong University.

IMHE researcher Cui Peng, chief scientist of the project, managed the seminar and raised four research objects for the Topic No.2. After group discussion, constructive proposals for the successfulimplementation of the project have been achieved: (1) key dimensionless numbers should be drawn from the study of the field cases (e.g., Zhouqu and Wenchuan large debris flows) and then used for the physical and numerical modeling design; (2) understanding of the dam-break process, and erosion and entrainment of granular mass in the channel are crucial for the study of the debris flow scale enlargement; (3) numerical simulation of debris flows should consider the rheological properties of granular flows; (4) evolution of the incomplete river blocking is a key point of this research and critical conditions should be proposed.