Dataset Direct Download Service (WFS): N_ZONE_ALEA_PPRN_20140164_S_032

The mapping of the hay removal of clays in the commune of Tirent-Pontéjac 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.本数据集提取自法国地质与矿产研究局（BRGM）编制的热尔省（Gers）官方图件，覆盖该省蒂朗-蓬泰雅克（Tirent-Pontéjac）市镇内的黏土区域，为黏土胀缩灾害相关的分区图。该图件为黏土胀缩现象发生概率的分区图。法国地质与矿产研究局（BRGM）首先以该省地质图为基础，基于纯物理准则编制了易发性图件，编图过程中针对各地质单元综合考量了以下因素：— 地质单元内黏土物质占比（岩相分析）；— 黏土相中膨胀性矿物占比（矿物组成分析）；— 该物质的岩土工程特性。针对已识别的各黏土地质单元，最终确定的灾害等级为上述易发性等级与归一化至每100平方公里实际出露城市化地表面积的灾害性胀缩事件密度的综合结果。