贵州省湄潭县风险斜坡特征及判定指标探讨

Characteristics and judgment index of risk slopes in Meitan,Guizhou Province

贵州省山地众多,地质灾害隐患多,发生频繁。为识别地质灾害危险源,贵州省开展了风险斜坡调查工作。通过分析关键孕灾因子,制定了风险斜坡现场判别表。湄潭县共发现风险斜坡172处,大部分为潜在土质滑坡,风险斜坡主要分布在寒武系及表层风化层中。对风险斜坡现场打分表部分指标(坡度、坡形、地下水埋藏深度、土地利用类型)进行了探讨,风险斜坡现场打分表应按潜在灾种分类设计或添加说明,坡度指标补充崩塌的适用性,坡形指标兼顾平面曲率对土质滑坡影响,地下水埋藏深度指标补充崩塌适用性,土地利用类型的林地指标应考虑植物根劈作用对潜在崩塌的不利影响和高大乔木对潜在滑坡的不利影响。

Mountainous areas abound in Guizhou Province and geological hazard occur frequently.To pinpoint the geological haz-ard sources,Guizhou Province has carried out a risk slopes survey.Through the analysis of key hazard factors,a site discrimination table of the risk slopes is established.In Meitan County alone,a total of 172 risk slopes have been identified,the vast majority of which have potential landslide risks and are mainly distributed in Cambrian and Ordovician strata and surface weathering layers.This paper discusses some of the indexes(slope gradient,slope type,burial depth of groundwater and land use type)in the field grading table.Suggestions are put forward that the risk slope table should be designed according to the classification of potential geological hazard types with descriptions added when necessary.The slope index supplements the applicability of collapse.The slope type index takes into account the influence of plane curvature on soil landslide.The underground water burial depth index supplements collapse applicability.The forest land index of land use type should consider the adverse effects of plant root splitting on potential collapses and the adverse effects of tall trees on potential landslides.