N_ZONE_ALEA_PPRN_20140423_S_032

The mapping of the hay removal of clays in the commune of Larée in the Gers department is extracted from the departmental mapping from the BRGM. This mapping is a zoning of the probability of occurrence of the phenomenon of shrink-inflating of clay soils. A susceptibility map was first drawn up on the basis of purely physical criteria by the BRGM from the geological maps of the department, which were interpreted taking into account the following factors for each geological formation: — the proportion of clay material within the formation (lithic analysis); — the proportion of blowing minerals in the clay phase (mineralogical composition); — the geotechnical behavior of the material. For each of the clay formations identified, the hazard level is ultimately the result of the level of susceptibility thus obtained with the density of sinister swelling, reported to 100 km² of actual urbanised outcropping surface.本数据集所涉图件提取自法国地质矿业研究局（BRGM）编制的热尔省官方图件，内容为热尔省拉雷公社范围内黏土胀缩相关分布。该图件实为黏土胀缩现象发生概率的分区图。 该敏感性图件最初由BRGM基于纯物理标准，依托该省地质图编制而成，编制过程中针对每个地质构造，综合考量了以下三类因素： — 地层内黏土物质占比（岩相分析）； — 黏土相内吹积矿物占比（矿物组成分析）； — 该物质的岩土工程特性。 针对已识别的各黏土地层，最终的灾害等级由前述得到的敏感性等级，结合每100平方公里实际出露城市化地表的膨胀灾害事件密度共同确定。