Dataset Direct Download Service (WFS): 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.法国热尔省伊佐热市辖区内黏土胀缩现象的图件提取自法国地质与矿产研究局（Bureau de Recherches Géologiques et Minières，BRGM）的省级图件。该图件为黏土土壤收缩-膨胀现象发生概率的分区图。法国地质与矿产研究局首先基于纯物理标准，依托该省地质图件编制了敏感性图件，编制过程中针对每个地质地层考量了以下因素： — 地层内黏土物质的占比（岩相分析）； — 黏土相中膨胀性矿物的占比（矿物组成）； — 材料的岩土工程特性。 针对已识别的每个黏土地层，最终的危险等级由上述得到的敏感性等级结合有害膨胀密度（按每100平方公里实际出露的城市化地表面积统计）共同确定。