广东沿海陆地地质环境质量定量评价研究

广东沿海陆地不仅是我国经济较为发达的地区 ,而且也是地震、水土流失、崩塌、滑坡、地裂缝、地面沉降、岩溶塌陷、软土地基形变等地质灾害较为频发的地区。基于对广东沿海陆地主要物理地质灾害形成条件与影响因素调查、统计与分析 ,将广东沿海陆地地质环境质量划分 :构造稳定性、斜坡稳定性和地基稳定性三个质量层面 ,进而构造了隶属三个层面的指标体系 ,该指标体系包括活动断裂、地震活动、地形起伏度、斜坡坡地、冲沟切割密度、水土流失程度、崩滑面密度、土体承载力和地裂缝面密度 9个指标。基于地质环境质量五值逻辑等级取值 :优等、良好、中等、较差和差等 ,对评价指标进行了相应地量化分级取值和标准化处理 ,在建立指标专家权重体系和线性隶属函数的基础上 ,构造了模糊数学综合评价模型。基于 Fortran程序对 190个剖分单元指标数据进行了模型运算 ,将广东沿海陆地地质环境划分为五个质量级共 17个地质环境质量单元。

QUANTITATIVE ASSESSMENT OF GEOLOGICAL-ENVIRONMENTAL QUALITY OF THE LAND ALONG GUANGDONG COAST

The land along the Guangdong coast is not only a relatively developed economical region,but also a friable geoenvironmental region. In the past few decades earthquake, soil erosion,ground lollapses, landslides, karstic sink, ground fissure, land subsidence, soft soil foundation deformation, etc. have caused considerable property damage and casualties, which is greatly related to the evolution of geoenvironment in the region. In the case it is very necessary to assess geoenvironment quality of the region. The occurrence of geological hazards reflects the variation of structure and state of geoenvironment in the region, which is further controlled by the geoenvironmental factors. Based on the investigation and statistic analysis of formation conditions of geologic hazards and influencing factors, the geoenvironment quality of the region can be divided into tectonic stability, slope stability, and foundation stability, then an index system for three layer surfaces was set up for geoenvironmental quality assessment. It includes active faults, earthquake activities, relief height, slope gradient, gulch incision density, soil erosion intensity, densities of collapses and landslides, soil mass bearing capacity, and ground fissure density. The geoenvironment quality is classified into five classes: best, good, moderate, worse, and worst, with linear subjection function of the indices and the weightings of 9 factors given by experts. A fuzzy mathematic model for multifactor comprehensive assessment was developed. Based on the model190 elements for the region were calculated with Fortran program. The result isshown in a zonation map of the geoenvironment quality, from that the result can be compared with the essential situation of the geoenvironment in the region, and it further indicates that the Fuzzy mathematic model developed is feasible and rational, and 17 geoenvironment quality subzones were distinguished. The result of assessment and zonation provide a necessary and sufficient information to users for urban construction planning, land rational use, and construction of major engineering works in the region.