黄土地区山区城镇地质灾害精细化风险“点面双控”体系

    Geological disaster refined risk “double-control of point and zone” system in mountainous towns of loess regions

    • 摘要:
      研究目的 黄土地区山区城镇地质灾害具有点多、面广的特点,当前的灾害管理模式以传统的隐患点管控为主,但近些年发生的地质灾害绝大部分均在管控范围之外,因此,现有的风险管控体系亟需创新与完善。
      研究方法 针对黄土地质灾害风险管控的复杂性,探索构建了一套适用于黄土地区山区城镇地质灾害的精细化风险“点面双控”体系。首先,对于“点控”环节,在野外调查的基础上进行地质灾害隐患点的稳定性、危害性和风险评价。其次,对于“面控”环节,以斜坡单元为基础选取适用于黄土地区的地质本底因子和地质灾害诱发因子,运用信息量法等统计学模型进行易发性和危险性评价,并考虑承灾体的易损性,评价斜坡单元的风险等级。最后,以行政村为基本单元,形成地质灾害风险“点面双控”一张图,提出适用于黄土地区的降雨预警八等级划分法,并制定相应的防御响应措施。
      研究结果 以陕西省榆林市米脂县主城区为案例,建立了地质灾害“隐患点+风险区”双控管理体系。研究结果表明,该区域共划分为57个行政村单元,其中极高风险隐患点1处、高风险隐患点14处、中风险隐患点1处、低风险隐患点5处、极高风险斜坡29处(面积占比0.45%)、高风险斜坡111处(面积占比2.19%)、中风险斜坡804处(面积占比19.35%)、低风险斜坡3596处(面积占比78.01%),并以此为基础编制了相应的地质灾害风险“点面双控”一张图,为地方政府防灾减灾提供了科学依据。
      结论 本研究为黄土地区地质灾害风险管控提供了新的思路,但仍处于探索阶段,未来需进一步深化技术与管理的融合,不断提升地质灾害社会化服务能力和水平。

       

      Abstract:
      Objective The geological disasters in mountainous towns of loess areas have the characteristics of many geological disaster points and wide areas. The current disaster management mode is mainly based on the traditional hazard point control, but most of the geological disasters in recent years are outside the scope of control. Therefore, the existing risk management and control system need to be innovated and improved.
      Methods In response to the complexity of loess geological disaster risk management, an exploratory methodology has been devised for a geological disaster refined risk “double−control of point and zone” system applicable to mountain towns in loess regions. Firstly, for the “point control” link, the stability, hazard and risk assessment of geological disaster hazard points are carried out on the basis of field investigation. Secondly, for the “zone control” link, geological background factors and geological disaster triggering factors suitable for loess regions are selected based on slope units, and statistical models such as information method are used to evaluate the susceptibility and hazard of geological disaster, and the risk level of slope unit is evaluated considering the vulnerability of disaster bearing body. Finally, a geological disaster risk “double−control of point and zone” map is formed based on the administrative village unit, and an eight−level rainfall warning division method is proposed for loess regions, along with corresponding defense and response measures.
      Results Taking the main urban area of Mizhi County in Yulin City, Shaanxi Province as a case study, a double control management system for “hazard points and risk areas” of geological disaster has been established. The study findings show that the area is divided into 57 administrative village units, with 1 extremely high risk hazard points, 14 high risk hazard points, 1 medium risk hazard point, 5 low risk hazard points, 29 extremely high risk slopes (accounting for 0.45% of the area), 111 high risk slopes (accounting for 2.19% of the area), 804 medium risk slopes (accounting for 19.35% of the area), and 3596 low risk slopes (accounting for 78.01% of the area). Based on this, a corresponding geological disaster risk “double−control of point and zone” map is drawn, providing scientific basis for local governments to prevent and reduce disasters.
      Conclusions This study provides a new insight for geological disaster risk management in loess regions, but it is still at an exploratory stage. In the future, we need to further deepen the integration of technology and management, continuously improve the geological disaster social service capacity and level.

       

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