基于地质调查的缓坡地建设适宜性评价——以福建省南平市建阳中心城区为例

Evaluation of construction suitability of gentle slope based on geological survey:A case study of Jianyang central district of Nanping City in Fujian Province

为构建缓坡地建设适宜性评价体系,合理划定缓坡地开发适宜区、一般适宜区及禁止建设区,科学开发利用低丘缓坡地资源,以福建省南平市建阳中心城区为研究区,在该区综合地质调查的基础上,以小流域为基本评价单元,以剥蚀阶地代替坡度和起伏度等指标,开展具有城镇建设功能指向的土地资源评价研究。以坡度、土体厚度、坡向-地层产状一致性,以及岩性建造、植被类型等为主要指标,进行地质灾害风险性评价,通过构建生态保护重要性、建设适宜性等多维评价体系,最终集成评价了缓坡地建设的适宜性。结果表明:研究区适宜城镇建设开发的缓坡地资源丰富,主要分布在严墩、新岭、兴田、将口、南林、赤岸、芹口等小流域的一级剥蚀阶地内,发生地质灾害的风险性较小,可以按照组团开发的方式逐步进行开发及利用,研究区属于地质灾害非易发区,但是西岸、水尾等小流域的二级剥蚀阶地、三级剥蚀阶地,土体较厚,坡度较陡,植被主要为杉木和毛竹,如果开发边界规划不合理,容易引发滑坡、崩塌等地质灾害。研究成果对我国低丘缓坡地合理开发利用具有较好的借鉴意义。

In order to construct the suitability evaluation system of gentle slope,and reasonably delimit development suitable area,general suitable area and forbidden construction area,the authors take the central district of Jianyang City in Fujian Province as the study case for scientific development and utilization of gentle slope resources.Based on comprehensive geological survey,the authors used small watershed as basic evaluation unit,and denudation terrace as a replacement for slope and fluctuation to conduct the evaluation of land resources with urban construction function.Geological hazard risk was assessed according to main indicators,including topographic slope,soil thickness,consistency of slope aspect and stratum occurrence,lithological construction and vegetation type.A multidimensional system of ecological protection importance and construction suitability was constructed to evaluate the construction suitability of gentle slope.The results show that the gentle slope suitable for urban construction in the central urban area of Jianyang is rich,mainly distributed in first-grade degradation terrace with little geological risk,including Yandun,Xinling,Xingtian,Jiangkou,Nanlin,Chi an,Qinkou and other areas,which can be developed and utilized step by step according to the way of cluster development.Jianyang central district belongs to non-prone geological risk area,but the second-grade and third-grade degradation terrace in Xi an and Shuiwei watershed have thick soil mass and steep slope with lanceolata and moso bamboo.Once the development boundary is unreasonable,these areas are easy to cause landslide and collapse and should be paid attention to.This research has some guiding effect on the rational development and utilization of low hills and gentle slopes in China.