N_ZONE_ALEA_PPRN_20140408_S_032

The mapping of the hay removal of clays in the commune of Bouzon-Gellenave in the Gers department is extracted from the departmental mapping derived 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（Gers）布宗-热勒纳沃（Bouzon-Gellenave）公社内黏土胀缩相关图件源自法国地质与采矿研究局（BRGM）编制的省域制图成果。该图件为黏土土壤胀缩现象发生概率的分区图。法国地质与采矿研究局（BRGM）最初依据纯物理准则，基于该省的地质图件编制了易发性图件，编制过程中针对每个地质单元，结合以下因素开展解译： — 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）； — 材料的岩土工程特性。 针对已识别的每个黏土地质单元，最终的灾害等级由上述易发性等级结合有害胀缩密度确定，该密度以每100平方千米实际出露的城市化地表面积为统计基准。