川西北红层地区崩滑体形成演化分析——以梓潼县某崩滑体为例  

Analysis on the Formation and Evolution of Collapse-landslide Accumulation in Red Beds,Northwest Sichuan:Take a Collapse-landslide Accumulation in Zitong County as an Example

作　　者：王毅 赵国华 王成功 Wang Yi;Zhao Guohua;Wang Chenggong(Nuclear Industry Southwest Geotechnical Investigation & Design Institute,Chengdu,Sichuan 610052)

机构地区：[1]核工业西南勘察设计研究院,四川成都610052

出　　处：《资源环境与工程》2022年第3期365-371,共7页Resources Environment & Engineering

基　　金：四川省梓潼县地质灾害防治技术支撑服务项目(510725202200031)。

摘　　要：四川盆地是中国主要的红层分布区,在川西北盆缘泥岩—砂岩—砾岩互层岩性分布区,崩塌、滑坡地质灾害频发。梓潼县某拟建场地的地表、冲沟及坡体内分布大量砂岩与砾岩孤石,还发育两处滑坡。为查明孤石来源及崩滑体成因,收集和分析区域地质及场地勘探资料,采用地质反演分析和工程地质分析相结合的方法,从地质地貌演化入手,初步揭示崩滑体的形成演化过程及模式。结果表明,崩滑体的形成演化与川西北红层地区特殊的地层结构和构造环境密切相关,在龙门山前缘扩展和隆升作用下,硬质岩(砂岩、砾岩)中发育陡倾共轭剪节理和软质岩(泥岩)中发育层间错动是内因;地壳抬升、河流溯源侵蚀、卸荷回弹等导致硬质岩节理张开并向临空方向崩塌和滑坡是外因。提出伴随地貌溯源发展,斜坡地带逐步形成一级或多级崩滑体的演化模式。研究成果对红层地区地质灾害研究和工程建设具有借鉴价值。Sichuan Basin is the main red beds distribution area in China.In the mudstone-sandstone-gravel interbedded lithologic distribution area of northwestern Sichuan,collapse and landslide geological disasters occur frequently.A large number of sandstone and conglomerate boulders are distributed in the surface,gully and slope of a proposed site in Zitong County,and two landslides are also developed.In order to find out the source of boulders and the genesis of collapse-landslide accumulation,the paper collects and analyzes regional geological and site exploration data,and uses geological inversion analysis and engineering geological analysis method,and starts from the geological and geomorphologic evolution,the formation and evolution process and mode of collapse-landslide accumulation are preliminarily revealed.The results show that the formation and evolution of collapse-landslide accumulation are closely related to the special stratigraphic structure and tectonic environment in the red beds of northwestern Sichuan.Under the expansion and uplift of Longmen Mountain front,the development of steeply inclined conjugate shear joints in hard rock(sandstone,conglomerate)and interlayer dislocation in soft rock(mudstone)are the internal causes.The opening of hard rock joints and collapse-landslide to the free direction caused by crust uplift,river erosion,unloading rebound and other factors are the external causes.It is proposed that with the development of landform traceability,the slope zone gradually forms the first-level or multi-level collapse-landslide accumulation.The research results have reference value for geological disaster research and engineering construction in red beds.

关 键 词：红层 崩滑体 崩塌 滑坡 坡体结构 形成演化 川西北 

分 类 号：P642.21[天文地球—工程地质学] P642.22[天文地球—地质矿产勘探]