工程弃渣泥石流易发性评估方法

Occurrence Probability of Channel Waste-slag Debris Flow Assessment

为了对工程弃渣转化成泥石流的可能性进行评估,针对工程弃渣特点,在考虑自然沟道泥石流活动情况的基础上,叠加弃渣场局部环境特征、弃渣体堆积特征及物料特征等三方面共计12个评价指标,运用层次分析法确立指标的权重,利用黄金分割法为各指标定量赋值,通过计算弃渣泥石流易发性指数RQ来评估工程弃渣泥石流的易发性,将评价结果分成4级:高度易发、中度易发、低度易发和不易发,并通过对长江三峡巴东县黄家大沟工程弃渣泥石流与重庆奉节李家大沟弃渣泥石流易发性进行评价,结果显示黄家大沟弃渣泥石流易发性指数为0.602(偏保守估算),属于中度易发,与实际发生泥石流较符合;李家大沟弃渣泥石流易发性指数为0.707,属于中度易发,与弃渣稳定性理论计算评价结果一致,验证了该方法的准确性和可行性。

In order to evaluate the probability of construction waste slag to debris flow, analyzed the characteristic of construction waste slag. Considering the activity situation of natural valley as well as the stability of waste slag field, 12 factors were choose for the assessment system based on AHP method. Defined RQ （ occurrence probability index of waste-slag debris flow） as the direct index, four level was divided as highly probability （ 1 - 0.75 ）, mod- erately probability （0.75 - 0.5 ）, lowly probability （0.5 - 0.25 ） and little probability （0.25 ~ 0 ） to depict the occurrence probability degree. Two instances were used to testify the accuracy of this method. One was Huangjia valley in Dan Ba county. The RQ was 0. 606, belonging to moderately probability, which was according with the reality that under consistence precipitation, waste slag debris flow was accrued in 2003. The other was Lijia valley in Chongqing Reservoir. The RQ was 0. 707, which demonstrated that it is quite possible to accrue waste slag deb- ris flow in this area. And the result was quite coincident with the theoretical calculation analyses did by Liu Fei （2010）.