Dataset Direct Download Service (WFS): Map of the haea removal of clays in the commune of Saint-Martin-Gimois (Gers)

The mapping of the hay removal of clays in the commune of Saint-Martin-Gimois in the Gers department is extracted from the departmental mapping derived 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.

该测绘成果取自法国地质矿业研究局（BRGM）生成的省级测绘数据集，针对热尔省圣马坦-吉穆瓦市镇内的黏土胀缩现象展开。该测绘为黏土土壤胀缩现象发生概率的分区图。法国地质矿业研究局首先以纯物理标准，基于该省地质图编制了易发性分区图，编制过程中针对每个地质单元考量了以下因素：
— 地质单元内黏土物质的占比（岩相分析）；
— 黏土相内吹积矿物的占比（矿物组成）；
— 岩土体的工程性状。
针对已识别的各黏土地层，最终的灾害等级由前述得到的易发性等级结合胀缩灾害密度计算得出，该密度以每100km²实际出露的城市化地表面积为基准进行归一化处理。