N_ZONE_ALEA_PPRN_20140369_S_032

The mapping of the hay removal of clays in the commune of Fourcès 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.热尔省富尔塞斯公社内黏土干草清除的制图成果源自法国地质矿产调查局（BRGM）的省级制图资料。该制图成果为黏土收缩-膨胀现象发生概率的分区图。法国地质矿产调查局（BRGM）最初基于纯物理准则，依托该省地质图件编制了易发性图，编制过程中针对每个地质单元，综合考量了以下因素：— 地层内黏土物质的占比（岩相分析）；— 黏土组分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。针对所识别出的每一处黏土地层，最终的灾害等级由前述得到的易发性等级结合有害胀缩密度（以每100平方千米实际出露的城市化地表为基准）共同确定。