N_ZONE_ALEA_PPRN_20140419_S_032

The mapping of the hay removal of clays in the commune of Labarthete 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.热尔省拉巴尔特特市镇内黏土胀缩灾害分布图提取自法国地质矿业研究局（Bureau de Recherches Géologiques et Minières，简称BRGM）编制的省级地质图件。该分布图为黏土胀缩现象发生概率的分区图。法国地质矿业研究局（BRGM）最初基于纯物理标准，依托该省的地质图编制了易发性图件，编制过程中针对每个地质单元，综合考量了以下因素：— 地质单元内黏土物质的占比（岩性分析）；— 黏土组分中膨胀矿物的占比（矿物组成分析）；— 该物质的岩土工程特性。针对每一个已识别的黏土地质单元，最终的灾害等级由上述易发性等级结合胀缩灾害发生密度确定，该密度以每100平方公里实际出露的城市化地表为基准进行统计。