基于SVM的地下采煤区沉陷灾害发育敏感性分区研究

SVM-based sensitivity zoning of subsidence disaster development in the underground coal mining areas

  • 摘要: 地下采煤区沉陷灾害发育重点区预测目前尚无固定程式,且敏感区预测结果存在不确定性较大的问题。以山西省太原市西山地区沉陷灾害为研究对象,分别以2012年和2014年核查编录的沉陷灾害数据为建模数据和验证数据,以高程、坡度、坡向、地势起伏度、地面曲率、地层岩组、地质构造为敏感性评价因子,综合运用GIS空间分析、统计分析和支持向量机(SVM)等方法,构建了4种核函数SVM沉陷灾害敏感性分区预测模型,分别从模型的评价因子权重、模型优选、敏感性分区预测结果、预测精度和模型适用性进行了分析。结果表明:多项式核函数SVM模型(PL-SVM)的训练精度(受试者特征曲线下面积AUC=0.854)与验证精度(AUC=0.755)均较高,模型预测能力良好,是4种模型中表现最好的模型,所划分敏感性分区结果合理,极高与高敏感区以较小面积分布较多沉陷灾害点,而低敏感区则以较大面积分布极少沉陷灾害点。PL-SVM模型预测的太原西山地区沉陷灾害发育极高、高、中和低敏感区的面积占比分别为:20.19%、17.43%、21.18%、41.20%,频率比值与敏感性等级之间呈良好的正相关,符合线性函数关系。PL-SVM模型敏感性评价结果可靠,适用性好,对地下采煤区沉陷灾害发育特征研究及灾害普查重点区预判具有参考意义。

     

    Abstract: At present, there is no fixed way to predict the sensitive zones of subsidence disaster development in underground coal mining areas, and the prediction result of sensitive zones has a great uncertainty. Herein, the subsidence disaster in Xishan area of Taiyuan City, Shanxi Province was taken as the research object. Totally 4 types of kernel SVM based prediction model for sensitivity zoning of subsidence disaster were constructed with the methods of GIS spatial analysis, statistical analysis and Support Vector Machine (SVM) in combination, taking the subsidence disaster data checked and recorded in 2012 and 2014 as the modeling and verification data respectively, as well as the elevation, slope gradient, slope aspect, topographic relief, surface curvature, stratigraphic strata and geological structure as the sensitivity assessment factors. Meanwhile, analysis was performed on the weight of assessment factors, the model optimization, the prediction results of sensitivity zoning, the prediction accuracy, and the applicability of models respectively. The results show that the polynomial kernel-SVM model (PL-SVM) has relatively high training accuracy (with the area under the receiver characteristic curve of AUC=0.854) and validation accuracy (AUC=0.755), as well as good prediction capability. Thus, it has the best performance among the 4 types of models, and the sensitivity zoning is reasonable, with more points of subsidence disaster distributed in a small area of the very-high and high sensitive zones, while few points of subsidence disaster distributed in a large area of the low sensitive zones. As predicted by the PL-SVM model, the area proportion of very-high, high, moderate and low sensitive zones of subsidence disaster in Taiyuan Xishan area is 20.19%, 17.43%, 21.18% and 41.20%, respectively. Besides, the frequency ratio and the sensitivity grade are in good positive correlation, showing a linear functional relation. The sensitivity assessment result based on PL-SVM model is reliable and has good applicability, which has reference significance to the study on the development characteristics of subsidence disasters in underground coal mining areas and the prediction of key areas in disaster survey.

     

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