不同精度下地表稳定性模型的评价

Model Evaluation of Geohazard Susceptibility in Different Resolutions

地质灾害易发性评价是地质灾害调查评价的重要内容之一。SINMAP(stability index mapping)模型耦合了无限斜坡模型和稳态水文模型,是应用最广泛的地质灾害易发性评价模型之一。该模型的输入参数包括地形数据、岩土物理力学参数、降雨量数据,其中数字高程模型(DEM)的精度对地形参数影响较大。为了探明不同DEM解像度对模型评价结果的影响,以浙江省温州市文成县玉壶流域作为研究对象,利用5、12.5、30 m三种不同精度DEM分别进行了SINMAP模型的地质灾害评价计算,并对结果进行了统计分析与比较。分析结果表明,DEM精度对SINMAP模型下地质灾害易发性评价结果呈现明显的非线性,5 m精度条件下的无条件不稳定区域接近12.5 m精度的两倍,30 m精度的3倍。日最大降雨量超过100 mm情况下降雨量对模型输出值的影响并不大。

Evaluation of geological hazard susceptibility is one of the important contents of geo-hazard investigation.SINMAP(stability index mapping)model is one of the most widely used models for the vulnerability of geological disasters,and it combines an infinite slope model with the steady-state hydrological model.The input parameters of the model include topographic data,rock-soil physical parameters,and rainfall data,among which the resolution of digital elevation model(DEM)has a great influence on topographic parameters.To explore the influence of different DEM resolutions on the model evaluation results,Yuhu watershed at Wencheng County,Wenzhou,Zhejiang Province was taken as the study case.Three different resolutions:5,12.5,and 30 m were used to calculate and assess the geological disaster in SINMAP model,and the results were statistically analyzed and compared.Results show that the DEM resolution was obviously nonlinear to the evaluation results of the vulnerability to geological disasters in SINMAP model,and the unconditional unstable region under the condition of 5 m resolution was nearly twice of those of the 12.5 m resolution and three times of the 30 m.In the case that the daily maximum rainfall value exceeded 100 mm,the influence of falling rainfall on the output value of the model was not significant.