摘要
坡积层斜坡可能滑移面的分析和确定是斜坡稳定性评价的基础和先决条件。通常情况下,大多数厚度不大的坡积层斜坡与下伏基岩接触面是斜坡堆积体的第一不连续面,也是斜坡失稳的滑移面。但对大型坡积层的斜坡,由于该类斜坡物质构成的差异和下滑动力解体原因,或滑前坡体内部应力场的变化常产生双层滑面,并在失稳过程中产生双层滑移。笔者在对新滩斜坡进行系统地质调查与研究的基础上,发现该斜坡在沿下伏基岩面发生整体下滑的同时坡体的上层还产生二次平行下滑,即产生双层滑移。这是不同其它滑移规律的一种独特滑移现象。在系统分析和研究双层滑移规律的基础上,本文建立了坡积层斜坡双层滑移物理模型,指出双层滑移模型是由双层滑移面和双层滑移体构成的。同时,根据滑面的组合关系和形成机制对斜坡滑移进行了分类,指出单层滑移可分为第一滑面型,第二滑面型和混合滑面型;双层滑移可分为惯性分异型和摩擦力控制型。本文在双层滑移物理模型基础上建立了双层滑移的数学模型并用以定量确定第二滑面(S_2)的临界深度。并用数学模型对新滩斜坡姜家坡段进行了定量计算并发现第二滑面深度的计算结果基本与斜坡失稳后的地表变化相吻合。
The analysis and determination of possible sliding planes is the basis and precondition for evaluation of a sliderock slope stability. Generally speaking, most contact planes between sliderock slopes and underlying bedrocks are just their possible sliding planes. But for the most large scale slideroek slopes may form double-sliding planes just due to the reasons such as the differences of slopes' composition, or sliding dynamics, or changes of stress field in slopes. So formed, double-sliding, On the basis of systemtical investigation and research on Xintan landslide, author has found that when the slope slided on the contact plane to bedrocks, the upper lager of the slope also produced the second parallel sliding, that is double sliding. This is a special sliding pattern different from other sliding regularities. Based on the double sliding law, the paper has established a physical model of double sliding and also pointed out that the model of double sliding is composed of double sliding planes and double sliding bodies. Acconding to the combining correlation of sliding planes and their forming mechanism, a classification for sliderock landslide has been carried out, pointing out that the landslide with single sliding plane can be divided into sliding- plane I, sliding-plane Ⅱ and combining sliding planes, the landslide with double-sliding planes can be divided into inertia differentia- tion and friction controlling type. It has also set up mathimatics models on the basis of Physical model and determined the critical depth of sliding-plaoneⅡ. Finally, some computations for Jiangjapo Section of Xintan Slope have been completed by means of the mathimatics models above. It is found that the computation results can basically coincide with the topography of the Slope offer landslide.
