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Commission on Discontinuous Deformation Analysis - DDA

Honorary Presidents

Prof. Gen-Hua Shi (USA, Founder)
Prof. Yuzo Ohnishi (Japan, Founder)
Prof. Yossef Hatzor (Israel, Fouding President)
Prof. Guo-Wei Ma (China, Founding President)


Prof. Yu-Yong Jiao


Prof. Gao-Feng Zhao


Secretary General

Prof. Jia-He Lv



Ai-Qing Wu (China)
Anna Maria Ferrero (Italy)
Guangqi Chen (Japan)
Hong Zheng (China)
Jae-Joon Song (Korea)
Jian-Hong Wu (Chinese Taipei)
M. Ronald Yeung (USA)
Nicholas Sitar (USA)
Tomofumi Koyama (Japan)
Xiao-Ying Zhuang (Germany)
Yuan Wang (China)
Zhiye Zhao (Singapore)

Resat Ulusay (ex officio), ISRM President
Suseno Kramadibrata (ex officio), ISRM VP for Asia

Terms of Reference

Purpose of the Commission

  • to continuously promote block theory, Discontinuous Deformation Analysis (DDA) method and Numerical Manifold Method (NMM) research for diverse rock mechanics and engineering applications;
  • to consistently provide a forum for exchanging ideas and research outputs on DDA;
  • to effectively organize ICADD conferences, workshops and training courses;
  • to develop more systematic learning materials on DDA;
  • to stimulate research interests and attract young generations to further develop DDA and its derived methods;
  • to enhance international collaborations on DDA;
  • to publish text book/s, educational software  on the theory and application of Block Theory, DDA, and its derived methods;
  • to conduct more industry applications of DDA theory with a joint work force.


Products of the Commission

  • The 15th and 16th International Conference on Analysis of Discontinuous Deformation (Osaka 2020, TBD 2022);
  • Two Proceedings Books on Discontinuous Deformation Analysis of the above International Conferences;
  • Three DDA Workshops discussing the latest development of discrete numerical methods and their application in rock mechanics and rock engineering;
  • Two DDA training courses at ISRM NG’s academic and research institutions around the world to be instructed by Commission members. We continue to conduct 1-2 such courses per year in the third term of the commission;
  • Uploading “student versions” of basic DDA and other discontinuous analysis packages on ISRM website including: DDA and its derived methods. Basic versions of those computer programs will be downloadable for individual ISRM members along with a manual with some worked examples and benchmark tests;
  • One Special Issue in an International Journal on discontinuous analysis and/or manifold method.