【作者】 丁岩；

【导师】 胡高社；

【作者基本信息】 长安大学 ， 地质工程， 2008， 硕士

【摘要】 滑坡是一种严重的斜坡变形现象,作为一种自然地质灾害,常常会给人们造成巨大的生命财产损失。我国是滑坡灾害多发国家,事先做出预报并采取有效的防范措施是减灾的重要手段。滑坡预报的核心是预报方法与预报判据。预报方法确定以后,如果没有正确的预报判据就无法进行准确的预报。由于预报判据的建立是比较困难的,国内外大量学者研究出了很多种预报判据,且对滑坡做出过成功预报。但是各预报判据都具有一定局限性,且都是不完善很难找到一个统一的定量指标或阀值。因此对滑坡预报判据的研究,必须建立在深入研究滑坡类型、滑坡特征、变形特点和形成机制的基础上,遵循科学性、综合性、易操作性的原则,对具体的滑坡进行具体的研究,找出影响滑坡稳定性的主导因素,从而得到适用于该滑坡的实际可行的预报判据。本文以三峡库区八字门滑坡为例,对其失稳判据进行研究。八字门滑坡是个古滑坡,属松散堆积型,1989年由于人类的工程活动复活后,随着三峡库水位的大幅抬高,滑坡体产生明显的裂缝,变形趋于明显。通过对该滑坡的变形特征及变形破坏机理研究知:三峡水库的不断蓄水、降雨和库水骤降是造成该滑坡变形复活的主要因素。本文主要从研究这三个因素对八字门滑坡稳定性的影响出发,研究滑坡失稳预报判据。本文运用包辛涅斯克(Boussinesq)方程研究了滑体中地下水浸润线随水库蓄水、降雨等的变化规律,并依据浸润线计算结果,分不同蓄水高度、不同库水下降速度、不同降雨强度等多种工况用极限平衡法对滑坡稳定性进行分析计算与综合评价。同时采用GTS有限元软件对该滑坡进行了其变形失稳破坏时的变形特征研究,确定了滑坡处于临界失稳状态时,滑体上不同部位的变形特征。基于上述研究成果,本文提出了以三峡库区水库蓄水高程、库水下降速度(降速)、库区降雨强度(雨强)为依据的滑体中长期失稳判据,以滑体特征部位的临界变形量、并结合滑坡临滑时可能出现的一些宏观现象等为依据的滑体临滑失稳判据,以供该滑坡的预警预报使用,同时其研究思路及结论也可供同类项目参考。更多还原

【Abstract】 The landslide is a serious deformation phenomenon, which can cause great loss to the life and property as a natural geological disaster. Our country is a country with much many geological disasters, so it is a good way to predict and prevent those disasters.The keys of landslide prediction are prediction method and prediction criteria.Once the prediction method is determinered, the landslide can not be predict correctly without the correct prediction criteria.It is difficult to establish the prediction criteria, and many prediction criterias have been studied by some researchers around the world.but any of these prediction criterias has its limitation,and can not be as a uniform index to predict landslide.So the study on the prediction criteria must be established on the basis of deeply research for landslide type, characteristics,deformation features and the forming mechanism ,together with the monitoring data, then find out the major effect factor for the landslide stability.Finally,the practical prediction criteria can be obtained.this article is taking the Bazimen Landslide as an example to study.Study the engineering geology exploration data carefully, make know the landslide type, characteristics, and deformation mechanism, then find out the major factor for the landslide deformation.The major effect factors of the landslide stability are the reservoir water repeated lifting and rainfall, which can affect the geotechnical strength, groundwater line and water pressure of the slope.In order to determine the effect by the water pressure of the slope, the simplified unground water line calculation formula is taken to calculate the underground water line of the slope, which is the preparation for the landslide wholly stability calculation.In order to determine the effect degree to the landslide stability by each factor,the way of limited equilibrium is taken to calculate the landslide stability under different impounding height,different water decreasing speed and different rainfall strength. In order to determine the deformation features of different position of the landslide, the finite element software GTS is taken to analysis the landslide doformation feature in the condition of the critical state.The level displacement value of feature point on the slope body is got under the condition of critical instability.The value will be taken as the prediction criteria of the landslide. On the basis of research results above, the impounding height, water decreasing speed, rainfall intensity, the deformation value of feature point on the slope body, together with some macroscopic phenomena of slipping time are taken as the predictiong criteria for the Bazimen landslide, which can be taken to predict warning the landslide, and its method and conclusion can be referred for other similar projects.更多还原