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岩质滑坡发生时间的适时超前预报是一个世界性难题,之所以长期不得其解,主要是缺乏对滑坡成生机理的明晰认识和未建立正确的量化模型。本文根据我国长江三峡工程库岸和西南山区积累的大量滑坡实例调查资料并参考国内外的一些研究成果,排除了地形控制论与地层控制论观点,阐明了滑坡形成的必要条件是斜坡具有易滑结构;滑坡发生的充分条件是有一定强度的诱发因素作用。故而诱发因素的动态变化对滑坡发生的时间具决定意义。鉴于地下水诱发的岩质滑坡分布最广,为建立正确的水力启动模型,本文归纳了近代典型岩质滑坡的主要特征:(1)滑面是导水性差异最大的贯通面;(2)滑体长度大而厚度小,长厚比多在20左右;(3)滑坡前缘段先启动;(4)临滑前在前缘段有渗水、冒水或喷水现象;(5)出水宽度之和远小于前缘段总宽度。根据这些特征和水力学、水文地质学的成熟理论指出Jennings(1970)等人提出的岩质斜坡稳定性模型存在下列问题:(1)未表明贯通面上岩体重力分布状况;(2)空隙水压力的分布特征与前述滑坡现象和水力学原理相悖;(3)未考虑通水率问题。然后,本文按顺向坡中的易滑超倾坡和椅状坡两个类型建立了斜坡稳定性模型和滑坡水力启动临界值(基本)计算公式。提出潜滑面的综合内摩擦角和通水率的确定方法:(1)滑坡反算;(2)对无水压滑坡滑面倾角和渗水边坡通水率进行观测统计;(3)剪切试验和简易水文地质试验;(4)物探方法。
It is a worldwide challenge that the timely prediction of rock landslide occurrence time is timely. The reason why it is indestructible in the long term is that there is no clear understanding of landslide mechanism and no correct quantitative model. Based on a large number of landslide accumulated survey data from the reservoir banks of the Three Gorges Project in the Yangtze River Delta and some mountainous areas in Southwest China and with reference to some researches at home and abroad, this paper excludes the topographic control theory and stratum control theory. It is clarified that the necessary conditions for landslide formation are that the slopes are slippery The sufficient condition of landslide occurrence is the inducing factor with certain strength. Therefore, the dynamic changes of induced factors are decisive for the time when landslides occur. In view of groundwater-induced rock landslides are the most widely distributed, in order to establish the correct hydraulic starting model, this paper summarizes the main features of modern typical landslides: (1) the slip surface is the penetrating surface with the greatest difference in water conductivity; (2) Length and thickness of the small, more than the length of the ratio of about 20; (3) landslide leading edge of the first start; (4) before the slippery slope in the leading edge of the water seepage, take water or water spray phenomenon; And far less than the total width of the leading edge. According to these characteristics and the hydraulics and hydrogeology theory, it is pointed out that the rock slope stability model proposed by Jennings (1970) et al. Has the following problems: (1) the rock mass gravity distribution on the through surface is not shown; (2) The distribution of water pressure is contrary to the landslide phenomenon and the principle of hydraulics. (3) The problem of water flow rate is not considered. Then, the slope stability model and the critical (basic) calculation formula of landslide hydraulic start-up are established based on two types of easy-slip super-slope and chair-slope in the forward slope. (1) Landslide inversion; (2) Observations and statistics of slope slip and seepage slope without water pressure landslide; (3) Scissors Cut test and simple hydrogeological test; (4) Geophysical methods.