N_ZONE_ALEA_PPRN_20140226_S_032

The mapping of the hay removal of clays in the municipality of Izotges 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）编制的热尔省域制图，为热尔省伊佐热市辖区内黏土胀缩相关的分区制图。该制图为黏土胀缩现象发生概率的分区图。BRGM最初基于纯物理标准，结合各地质构造的以下影响因素，依托该省地质图编制得到敏感性图： — 构造内黏土材料占比（岩相分析）； — 黏土相中的吹扬矿物占比（矿物组成）； — 材料的岩土工程特性。 最终，针对每个已识别的黏土构造，其危险等级由上述敏感性等级结合灾害性胀缩密度确定，该密度以每100km²实际出露的城市化地表为基准进行折算。