Studies Of Monitoring And Early Warning On Debris Flow In The Shahe Basin In Beijing Area

Since the founding of PRC, debris flow -one type of sudden geological hazard has caused the largest scale casualties (around 502 men were killed, and direct economic losses as much as several hundred million dollars were incurred) in Beijing Area. In view of the fact that local government and scholars paid attention to the disaster prevention and research work, it is therefore significant theoretically and practically to research on debris flow monitoring and early warning system in Beijing area. The author takes the Shahe basin as study area near the boundary of Huairou district and Miyun district. Based on fully investigation for theoretic research on the debris flow forecast, development status of debris-flow ditch is systematically summarized. This article illustrates modelling theory and technical methods of monitoring & early-warning system of debris flow. In addition, system software is developed and applied to forecast analysis of the study area.Modelling is the theory core of this article. First of all, seven evaluating indicators are selected according to features of the debris flow ditch in the Shahe basin. Extension theory is used to build risk evaluation zonation model with multiple indexes. Secondly, after statistical analysis of relationship between debris flow events and raining process, rainfall early-warning grades are confirmed by the Logistic regression model. Finally, rainfall grades and risk evaluation zonation were united by debris flow forecast model applied to the study area.Technical methods are the highlights of this article. By means of installing monitors and previous studies, the author raises warning threshold values for the short-term prediction. Trigger factor and saturated state are monitored by hyetometers and soil moisture meters. Infrasound detectors are used to catch infrasound signals after the formation of debris flow. Mud meters monitor flow depth to deduce the scale.System software is the technology core of this article.This system integrates above two parts into uniform platform to realize early warning intelligently. And the system consists of four parts:platform, function module, database and early warning model. Six subsystem and twenty-four modules which operate independently are comprised by the system. At last, the author realizes forecast analysis of the Shahe basin to testify its feasibility.The completed system is set up from modelling, technical methods and system software. It builds the foundation of early warning and enhances ability to monitor debris flow disaster in the Shahe basin.