罗小杰. 2015: 也论覆盖型岩溶地面塌陷机理. 工程地质学报, 23(5): 886-895. DOI: 10.13544/j.cnki.jeg.2015.05.009
    引用本文: 罗小杰. 2015: 也论覆盖型岩溶地面塌陷机理. 工程地质学报, 23(5): 886-895. DOI: 10.13544/j.cnki.jeg.2015.05.009
    LUO Xiaojie. 2015: FURTHER DISCUSSION ON MECHANISM OF COVERED KARST GROUND COLLAPSE. JOURNAL OF ENGINEERING GEOLOGY, 23(5): 886-895. DOI: 10.13544/j.cnki.jeg.2015.05.009
    Citation: LUO Xiaojie. 2015: FURTHER DISCUSSION ON MECHANISM OF COVERED KARST GROUND COLLAPSE. JOURNAL OF ENGINEERING GEOLOGY, 23(5): 886-895. DOI: 10.13544/j.cnki.jeg.2015.05.009

    也论覆盖型岩溶地面塌陷机理

    FURTHER DISCUSSION ON MECHANISM OF COVERED KARST GROUND COLLAPSE

    • 摘要: 为了更好地给覆盖型岩溶地面塌陷的处置和防治提供理论依据,根据可溶岩上覆盖层物质成分、地质结构及其物理力学性能的差异,首次将覆盖型岩溶地面塌陷机制区分为沙漏型、土洞型和泥流型3种类型。砂性土层分布区,由外界因素的触发导致沙颗粒向岩溶通道和溶洞漏失而产生的地面塌陷现象称为沙漏型塌陷。重力和岩溶提供的有效空间是产生沙漏型塌陷的必要条件,地下水作用加速了沙漏型地面塌陷发生,缩短了塌陷发生的过程。发生在黏性土和密实砂性土层中、由于土洞洞顶拱效应失效而产生的地面塌陷现象称为土洞型塌陷; 天然土洞通过地表水侵蚀与地下水潜蚀作用、砂土漏失和软土流失等3种方式形成; 土洞的形成和发展时期内洞顶上方土体是稳定的,在外部因素触发而导致洞顶拱效应失效时才发生地面塌陷; 土洞型塌陷具有隐蔽性和突发性的特点。由软弱土体流失而产生的地面塌陷现象称为泥流型塌陷。泥流型地面塌陷是软弱土体向溶蚀通道和溶洞中流失的结果。岩溶地面塌陷的触发因素包括地下水作用(垂直和水平渗流、土/岩界面处地下水位频繁波动)、外加荷载(动荷载和静荷载)和土洞顶板抗力降低(顶板强度降低、厚度减薄和结构破坏)等方面。这些外因触发了岩溶地面塌陷的发生。

       

      Abstract: In order to better provide a theoretical basis for the treatment and prevention of the covered karst collapse(CKGC),according to the differences of material composition, geological structure, physical and mechanical properties of overburden on karst, for the first time, CKGC is divided into three types of mechanism, which are respectively called by hourglass type collapse, soil-cave type collapse and soft soil flow type collapse. In the distribution area of sandy soil, hourglass type collapse is caused by sand particles loss to the karst channels and karst caves because external factors triggering. Gravity and effective space provided by karst are necessary conditions for the occurrence of hourglass type collapse, and the role of groundwater accelerates the occurrence and shortens the process of hourglass type collapse. The ground subsidence phenomenon caused by soil-cave roof arching failure is called soil-cave type collapse occurring in clay and dense sand soil. The natural soil-cave is formed by three ways of the surface and groundwater erosion action, sand loss and soft soil flow. The roof of soil-cave is stable in the period of the formation and development of soil-cave, and ground subsidence occurs when the cave roof arching failure by triggering of external factors. The soil-cave type collapse has the characteristics of concealment and burst. The ground subsidence phenomenon caused by the soft soil flow is called as soft soil flow type collapse, is the result of the soft soil loss through karst channel and cave. The triggering factors of CKGC include groundwater action(vertical and horizontal seepage and underground water level frequent fluctuation at the soil/rock interface),external load(dynamic load and static load) and soil-cave roof resistance reduction(strength and thickness decrease and structure destruction of the roof).These external factors trigger the occurrence of CKGC.

       

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