四川宜宾市地质灾害隐患与地层岩性-地质构造关系分析

Analysis on the relationship between geological hazard and lithology,geological structure in Yibin City of Sichuan Province

针对宜宾市地质灾害数量大、类型多、分布不均等问题,以宜宾市地质灾害隐患与地层岩性-地质构造耦合关系为切入点,在资料搜集、遥感解译、野外调查的基础上,分析总结了地层岩性、地质构造对地质灾害隐患的控制效应,可为宜宾市地质灾害防灾减灾工作的分区部署提供科学支撑。研究结果表明:宜宾市地质灾害隐患与地层岩性关系密切,滑坡(含不稳定斜坡)、崩塌、地面塌陷在软硬相间的块状-层状碎屑岩岩组中广泛分布,较坚硬层状-块状碳酸盐岩岩组与软硬相间碎屑岩岩组的过渡部位亦有利于崩塌的发育,泥石流则分布在易被风化、可提供丰富物源的岩组中。区域地质构造控制了地质灾害隐患的整体分布,主要表现为褶皱、断层走向与地质灾害隐患整体展布具有一致性。对于不同的局部构造环境,地质灾害隐患发育程度明显不同,在褶皱构造中地质灾害隐患主要分布在距褶皱核部2 km以外的区域,距离褶皱核部越远,地质灾害隐患点密度有逐渐增大的趋势;在断层构造中距断层面越近地质灾害隐患点密度越大,距离在1 km以内断层对地质灾害隐患的控制效应尤为明显。大致以高县凤滩村—江安县和平村为界,研究区北部应重点关注滑坡(含不稳定斜坡)地质灾害隐患,建议采取群测群防的防治措施,南部应重点关注崩塌、地面塌陷地质灾害隐患,建议采取专业监测、搬迁避让的防治措施。

Based on the large number,diverse types and uneven distribution of geological disasters in Yibin City,this study takes the coupling relationship between geological disaster and lithology-structure as a starting point.Through data collection,remote sensing interpretation and field investigation,this study analyzed and summarized the control effects of formation lithology and geological structure on geological disasters.The findings can provide scientific support for the zoning and deployment of geological disaster prevention and mitigation in Yibin City.The results show that geological disasters in Yibin City are closely related to lithology.Landslides(including unstable slopes),collapses,and ground collapses are widely distributed in soft and hard massive layered clastic rock formations.Additionally,the transition zone between hard layered massive carbonate rock formation and soft hard clastic rock formation is conducive to the development of collapse.Debris flows are distributed in rock formations that are easily weathered and can provide rich material sources.Regional geological structure also influences the overall distribution of geological disasters,particularly the consistency between the strike of folds and faults and the overall distribution of geological disasters.The degree of geological disaster development varies with different local tectonic environments.In fold structures,geological disasters are primarily concentrated within 2 km of the fold core,with density increasing gradually as the distance from the fold core increases.In the fault structure,the density of geological disasters points increases as one approaches the fault plane,with the control effect of faults on geological disasters particularly evident within 1 km.This study recommends that the northern part of the study area,specifically Fengtan Village in Gaoxian County and Heping Village in Jiang’an County,prioritize landslide prevention and control measures,such as group prevention and group strategy.In contrast,the southern part should prioritize measures to prevent and control collapses and ground collapses,such as professional monitoring,relocation,and avoidance.