• 主管:

      天津市地质矿产勘查开发局

    • 主办:

      天津地热勘查开发设计院

    • ISSN

      1001-1412  CN 12-1131/P

    秦安县郭嘉镇滑坡发育特征与成因机理研究

    Development Characteristics and Formation Mechanism of Landslides in Guojia Town, Qin’an County

    • 摘要: 以秦安县郭嘉镇滑坡为研究对象,采用野外地质调查等方法,在乡镇尺度系统开展了区内25处滑坡发育特征、形成机理及成灾模式研究。结果表明:镇域内以舌形中层黄土滑坡为主要类型,滑坡变形破坏严重程度依次为滑坡的前缘-中部-后缘。黄土层内滑坡受控于坡体形态产生的最大剪应力带,在长期风化、降雨入渗作用下贯通形成滑面,此类滑坡滑动速度快,滑动完成后整体趋于稳定。黄土-泥岩接触面滑坡在其接触面易于汇集地下水,在泥岩顶部形成软弱结构面,一般沿着破裂面在雨季或丰水年产生缓慢蠕滑。黄土-泥岩复合滑坡在自重、地下水等长期作用下,降雨沿裂缝下渗至泥岩接触面,致使岩土界面抗剪强度发生突变,滑面多沿基岩中的节理启动。镇域内滑坡的致灾模式分为“滑移变形+掩埋或推倒破坏”和“滑移变形+拉裂破坏”两种。基于此,针对不同类型滑坡的具体特征提出切实有效的治理措施。研究结果为潜在滑坡隐患的早期判识及防灾治理策略的制定提供了科学依据。

       

      Abstract: This study takes the landslides in Guojia Town, Qin'an County as the research object. Through field geological surveys, drilling, it systematically investigates the development characteristics, formation mechanisms, and disaster modes of 25 landslides at the township scale. The results show that tongue-shaped medium-layer loess landslides are the predominant type (20 sites, 80 %), with the severity of deformation and damage decreasing from the front to the rear of the landslides. Loess landslides are primarily controlled by the maximum shear stress zone within the slope; under long-term weathering and rainfall infiltration, the shear zone progressively develops into a continuous sliding surface. These landslides tend to move rapidly during failure and generally stabilize after sliding. Loess-mudstone interface landslides are characterized by groundwater accumulation at the loess-mudstone contact, where the underlying mudstone top forms a weak structural zone. These landslides typically exhibit slow creep along the contact surface during rainy seasons or wet years. Loess-mudstone composite landslides are driven by the coupling of self-weight stress and long-term groundwater action; rainfall infiltrates along cracks to the mudstone contact, causing a sudden reduction in shear strength at the soil-rock interface, with sliding surfaces often initiating along joints within the bedrock. The disaster modes of landslides in the town are classified into two types: “slide-tension cracking type” and “creep-tension-shearing type,” with damaging effects on structures and farmland categorized as either “tensile failure” or “burial or toppling failure.” Finally, graded mitigation measures are proposed according to different landslide types and threat levels. The results provide a scientific basis for the early identification of potential landslide hazards and the formulation of disaster prevention strategies.

       

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