Dataset Direct Download Service (WFS): N_ZONE_ALEA_PPRN_20140359_S_032

The mapping of the hay removal of clays in the commune of Bonas 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.本绘图源自法国地质矿业研究局（BRGM）编制的热尔省官方地质图，覆盖热尔省邦纳斯市镇内的胀缩性黏土相关内容。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）首先依托该省地质图，基于纯物理标准编制了敏感性分区图，编制过程中针对每个地质构造，综合考量了以下因素： — 地层内黏土物质占比（岩相分析）； — 黏土相中膨胀性矿物的占比（矿物组成分析）； — 该物质的岩土工程特性。 针对已识别的每个黏土构造，最终的灾害等级由前述得到的敏感性等级结合灾害性胀缩密度（按每100平方公里实际出露的城市化地表面积统计）确定。