福建南安市地质灾害特征及防治对策

Characteristics of the geological hazards and their countermeasures in Nan'an City of Fujian Province

根据福建省南安市地质灾害调查和区划工作成果,总结该区地质灾害类型主要有滑坡、崩塌和泥石流,尤以滑坡和崩塌的危害性最大。全市共发现地质灾害140处,其中滑坡72处(含土质滑坡67处),崩塌65处(土质崩塌55处),泥石流3处。南安市地质灾害具有分布广、规模小、突发性强、危害性大等特点,其控制因素:包括地形地貌、岩土体性质、降雨和人类工程活动等。南安市属于低山丘陵地貌,其中低山山地占全市面积的50%,丘陵、台地占25%;花岗岩、凝灰岩分布面积广,其残积层厚度较大,约5～17m,岩性为残积砾(砂)质粘性土,是致灾的主要土体。98%的地质灾害与降雨有直接的关系,当过程雨量达到100mm时,滑坡开始产生;过程雨量大于200mm时,滑坡普遍发生。直接与人类工程活动有关的地质灾害共134处,占地质灾害总数的95%,坡脚开挖是引发地质灾害的主要因素,占调查总数的84 4%。论文还提出了地质灾害防治的相应对策。

Rockfall,landslide,debris flow are the main types of geological hazards in Nan'an city,Fujian province. 67 soil landslides,5 rock landslides,55 soil falls,10 rock falls and 3 debris flows have been found in Nan'an City,with the characteristics of wide distribution,frequent,and sudden occurrence and severe damage.The factors affecting the geological hazards include landform,rock and soil type,rainfall and human activity.The low-mountain and hilly areas account for 75% of the whole area,the eluvium soil of the granite and tuffecesus rock are widely scattered,with the depth of 5-17 m and composed of the sandy clay.These hilly areas with thick sandy clay are prone to landslide.98% of the geological hazards were induced by rainfall,the rainfall in succession is the main indicator to predict the landslide in this area,the rainfall of 100 mm,200 mm in succession imply the initiation and frequent occurrence of landslide respectively.Those induced by the slope cutting account for 84% of all the geological hazards.The control measures for geological hazard have also been proposed in this paper.