Dataset Direct Download Service (WFS): Mapping of the hay removal of clays in the commune of Marsan (Gers)

The mapping of the hay removal of clays in the commune of Marsan 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.

本数据集源自法国热尔省马桑市镇内的黏土胀缩（shrink-inflating）现象制图，其数据提取自法国地质与矿业研究局（BRGM）编制的省级制图成果。该制图为黏土胀缩现象发生概率的分区图。法国地质与矿业研究局（BRGM）最初基于纯物理准则，依托该省的地质图编制了敏感性图，编制过程中针对每一种地质单元，综合考量了以下因素：——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。针对每一种已识别的黏土地质单元，最终的灾害等级由前述敏感性等级结合灾害性胀缩的发生密度计算得出，该密度以每100平方千米实际出露的城市化地表为基准进行归一化处理。