泥石流起动原型试验及预报方法探索

Experimental simulation of rainfall-induced debris flow by in situ test and forecast method

在分析国内外泥石流预报的基础上,结合泥石流形成机理研究取得的进展,提出了新型的暴雨泥石流预报方法。通过蒋家沟泥石流源地人工降雨试验,坡面泥石流形成与源地土体特征参数变化存在密切的关系。暴雨泥石流形成的过程可以描述为:降雨→土体含水量、土体结构和土体组成的变化→土体强度变化→斜坡稳定性变化→坡面泥石流形成→沟谷泥石流。建立起前后两者的关系,用降雨并结合中间关系方程分析泥石流发生的概率、时间及形成规模等参数,逐步提高泥石流预测预报精度。比传统的预报方法在精度上有很大的提高,使对误差进行估算成为可能。

On the base of civil and foreign achievements about debris flow forecast, a new-type debris flow forecast method is presented after new research achievements about the debris flow formation mechanism were analyzed. After the man-made rainfall experiments were done at the source region of debris flow in Jiangjia Ravine, we find that there are close relationships between the formation of debris flow located at slope and soil characteristic parameters..These parameters include water potential, water content, pore pressure, soil strain and soil temperature. To rainfall-type debris flow, the process of debris flow formation can be expressed： rainfall process → change of soil water content, change of soil structure and composition → change of soil strength→ change of slope stability → soil broken （start of landslide） → formation of debris flow on slope→ formation of debris flow in gully. If we set up the relationship between former step and latter step, we can forecast the occurrence probability, occurrence time and form scale of debris flow using rainfall data, so we can improve the precision of debris flow forecast step by step. To compare new achievement with traditional methods, we find that we not only improve the precision of debris flow forecast but also can estimate the error of debris flow forecast.