遵义地区降水型滑坡和泥石流前兆强信号研究

A Study on Previous Stronger Signal Model of Landslide-debris Flows Caused by Precipitation in Zunyi Region

该文针对贵州省68个土壤湿度站和降水资料做相关性分析,结果表明土壤湿度与降水的相关性体现在集中降水的同步对应关系和持续性降水的滞后相关关系上,土壤湿度与前期降水的正相关关系随前期降水日数的累积而增加,且在4~6 d左右达到稳定。基于遵义地区28例降水型滑坡泥石流灾害个例,分型讨论了土壤湿度增量的垂直分布和水平分布特征,说明在引入模型时应该主要考虑表层(10~20 cm)的土壤湿度的变量累计,根据降水类型的不同需要分型讨论变量引入模型的统计时段。在以上研究基础上,建立了能够同时反映降水和土壤湿度中短期变化特征的降水型滑坡泥石流前兆“强信号”指标模型。模型分集中降水型和分散降水型两种情况,并包括降水变量和土壤湿度变量两项,分散型模型的统计时段为灾害日前两日内,集中型模型的统计时段为灾害日前6日内,权重系数是根据研究地区的降水类型、土壤类型和田间持水量等相关因素的配置综合考虑和调整后确定的经验系数。对遵义地区23个个例建立模型并检验的结果较好。

In this paper,68 soil moisture stations and precipitation data in Guizhou province were analyzed,the results show that the soil moisture was closely related to rainfall,reflecting the synchronous correlation of concentration rain type and the lag correlation of persistent rain type;as the day of accumulative rain days increased,the former positively correlation is better,and a plateau is reached when the rain days accumulated to 4~6 days;Based the twenty-eight landslide-debris flows cases caused by precipitation of Zunyi region,the variable temporal and spatial characteristics of the soil moisture shows that,the moisture in the surface of soil layer(10~20 cm)is important to the previous stronger signal model,the statistical time range should be different under the landslide-debris flows caused by different types of rain.Previous stronger signal model of landslide-debris flows caused by precipitation under different types of rain is built,which can reflect the short-middle anomaly characteristics of rainfall and soil moisture,including the variable of rainfall and soil moisture,the statistical time range of concentration rain type is the growth of former two days rain and soil moisture,and that of the persistent rain type is six days,the weight coefficient is determined by the regional influences,including rain type,soil type,field capacity and so on.The model was established for 23 individual cases in Zunyi area and the test results were good.