Dataset Direct Download Service (WFS): N_ZONE_ALEA_PPRN_20140211_S_032

The mapping of the hay removal of clays in the commune of Duffort 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.热尔省杜福尔市镇范围内粘土胀缩相关图件，源自法国地质矿产调查局（BRGM）的省级测绘成果。该图件为胀缩性粘土现象发生概率的分区图。法国地质矿产调查局（BRGM）首先基于纯物理准则，依据该省地质图件编制了敏感性图件，编制过程中针对每个地层均综合考量了以下因素： — 地层内粘土物质占比（岩相分析）； — 粘土相中吹蚀矿物占比（矿物组成）； — 材料的岩土工程特性。 针对已识别的各粘土地层，最终的灾害等级由上述所得敏感性等级结合有害胀缩密度，并以每100平方公里实际出露的城市化地表为基准进行折算。