Dataset Direct Download Service (WFS): N_ZONE_ALEA_PPRN_20140303_S_032

The mapping of the hay removal of clays in the commune of Sainte-Christie in the department of Gers 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）编制的省域地质绘图中热尔省（Gers）圣克里斯蒂公社（Sainte-Christie）的黏土吹除绘图。该绘图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（BRGM）首先基于纯物理准则，利用该省地质图编制了敏感性分区图，编制过程中针对每个地质构造，在对地质图进行解译时纳入了以下影响因素： — 地层内黏土物质占比（岩相分析）； — 黏土相中风蚀矿物占比（矿物组成）； — 岩土体的工程特性。 针对已识别的各黏土构造，最终的灾害等级由前述敏感性等级结合有害胀缩密度确定，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统计。