Hazard-evolution Control Of Debris Flow And Modelization Analysis Methods

The concept for debris hazard mitigation mainly follows the pre-disaster prevention patterns of unblocking, inception, and drainage, etc. The analytical methods are not systematic, and some of those are relatively empirical, however. If it is possible to provide theoretical analysis models for the active debris hazard mitigation like pre-disaster prevention and post-disaster responding preparation, it would contribute to implement active hazard mitigation, and achieve the target of "prevent disaster before it happens, and reduce the loss after it happens" more effectively. Around the issues of modeling analysis for debris flow hazard mitigation, relying on the research project of debris flow hazard mitigation in Ya-Lu highway and the scientific research projects aiming at the disasters of debris flow and rock avalanche in the M8.0 Wenchuan Earthquake and the M9.0 East Japan Earthquake, this paper discussed a series of analysis models for debris flow hazard mitigation, aimin at more normative, quantified and engineering adaptable. The main research work and achievements are as follows:(1) With the model concepts and methods of System Theory and Cybernetics, this paper normalized the establishment of analysis models in debris flow hazard mitigation, in which a basic model system are proposed as a result, concerning about the issues of debris flow's hazard loss prediction, hazard status estimation, mitigation effect prediction and mitigation program optimization;(2) In the research on the calculating model of debris flow's hazard losses, this paper established an expression of the relation between debris flow's hazard losses and hazard influencing factors by analogizing the strength condition formula of material failure. The expression was called as the debris flow hazard-evolution model. This model testified the rationality of multiplication between hazard and vulnerability in the risk analysis model theoretically, and revealed the influence to the hazard risk of debris flow by the ground condition in hazard bearing regions. The model can be used both in the risk prediction and hazard status estimation;(3) In the view of the regulating effects of debris flow's hazard mitigation measures towards the hazard influencing factors, this paper established the hazard-evolution control model for debris flow, and proposed optimizing analysis model for debris flow's hazard-evolution control and basic pattern for hazard-evolution control as well as the analysis method of feasible program set under the framework of mathematic planning method, which provided a relatively convenient theoretical approach for the analysis in debris flow's hazard mitigation effects and the propose and optimization of mitigation program;(4) For the basic theoretical issue of debris flow's hazard mitigation analysis, this paper discussed the triggering phenomena and resistance laws of debris flow, and pointed out the relativity between debris flow's triggering and moving. Through taking debris flow'triggering and moving an entirety into consideration, a formula for debris flow rough ratio calculation based on the law of conservation of momentum was deduced in this paper, which provided a more objective theoretical method for establishing the rough ratio coefficient.