N_ZONE_ALEA_PPRN_20140424_S_032

The mapping of the hay removal of clays in the commune of Laujuzan 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（Gers）洛瑞藏市镇（Laujuzan）内的黏土胀缩相关图件源自法国地质矿产调查局（BRGM）编制的省级测绘成果。该图件为胀缩性黏土现象发生概率的分区图。 法国地质矿产调查局（BRGM）首先依托该省地质图，以纯物理准则编制了易发性分区图，编制过程中针对各地质单元，综合考量了以下影响因素： — 地质单元内黏土物质占比（岩性分析）； — 黏土相内膨胀矿物占比（矿物组成分析）； — 岩土体的工程性状。 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灾害性胀缩密度的综合结果，该密度以每100平方千米实际城市化裸露地表为统计基准。