N_ZONE_ALEA_PPRN_20140463_S_032

The mapping of the hay removal of clays in the commune of Verlus 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.法国热尔省韦尔吕斯公社内黏土胀缩现象的制图成果，源自法国地质矿产调查局（BRGM）编制的省级地质制图。该制图为黏土胀缩现象发生概率的分区图。法国地质矿产调查局（BRGM）最初以该省地质图为基础，基于纯物理标准编制了易感性图；编制过程中针对每个地质地层，参考了以下解释因素： — 地层内黏土物质占比（岩相分析）； — 黏土相内膨胀性矿物占比（矿物组成）； — 该物质的岩土工程特性。 针对所识别的每一处黏土地层，最终的灾害等级由上述易感性等级结合有害胀缩密度（以每100平方千米实际城市化出露地表为基准）计算得出。