Dataset Direct Download Service (WFS): N_ZONE_ALEA_PPRN_20140431_S_032

The mapping of the hay removal of clays in the commune of Luppé-Violles 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.本数据集提取自法国地质矿业研究局（BRGM）编制的热尔省官方制图，内容为热尔省吕佩-维奥勒（Luppé-Violles）市镇范围内黏土胀缩现象的发生概率分区图。该敏感性制图最初由BRGM基于纯物理准则，以该省地质图为基础编制而成，解译过程中针对各地质地层综合考虑了以下因素： — 地层内黏土物质占比（岩相分析）； — 黏土相中膨胀矿物的占比（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破坏性胀缩密度确定，该密度以每100平方千米实际出露的城市化地表为统计基准。