库水位下降速率对三峡库区丰都段滑坡稳定性影响研究

发布时间：2018-06-01 04:30

本文选题：三峡库区 + 丰都　；参考：《成都理工大学》2016年硕士论文

【摘要】：三峡库区是滑坡多发区,随着水库蓄水,库区内大量老滑坡产生不同程度的变形复活。提高库水位日降幅势必对滑坡稳定性造成更大影响,所以开展此项研究很有必要。研究区位于重庆市丰都县,距离三峡大坝434km,库段全长49km,区内水库滑坡分布广泛,对生命财产造成巨大威胁,其中代表性的较大滑坡共有36处。提高库水位日降幅破坏了滑坡原有的平衡状态,有可能导致滑坡复活。在保证滑坡稳定性的前提下提高库水位日降幅,既不会导致灾害的发生,又能提高水库经济效益,因此,研究库水位下降速率对区内滑坡稳定性的影响具有重要的实际意义。本文以三峡库区丰都段水库滑坡作为研究对象,在充分分析了研究区地质环境条件、滑坡发育特征基础上,对研究区滑坡的发育规律进行了详细研究,并对滑坡进行分类,研究了滑坡稳定性影响因素及变形机理。最后利用定性评价和定量评价综合分析了研究区滑坡稳定性现状以及增大库水位日降幅条件下稳定性预测。经过上文研究,得到如下成果:(1)研究区滑坡发育在J2s、J3s、J3p地层中,岩性主要为砂岩、泥岩,可分为三类工程地质岩组:Ⅰ、坚硬厚层状砂岩为主;Ⅱ、软硬相间层状砂岩、粘土岩互层;Ⅲ以软弱层状粘土岩为主。滑坡变形模式主要为蠕滑-拉裂式、滑移-拉裂式,少量为滑移-弯曲式。(2)对研究区滑坡按照工程地质岩组进行统计可以得出:Ⅰ类岩组发育滑坡8处,Ⅱ类岩组发育滑坡13处,Ⅲ类岩组发育滑坡15处。不同工程地质岩组中发育的滑坡堆积体物质组成也存在差异,对应于工程岩组分类,将堆积体分为三类:Ⅰ、前缘大块石+中部、后部粉质粘土夹碎块石;Ⅱ、粉质粘土夹碎块石+前缘坡表堆积砂岩块石;Ⅲ、粉质粘土为主,夹泥岩碎块石。(3)对区内滑坡按照库水作用划分为三类:(1)动水压力型,共发育23处;(2)浮托减重型,共发育3处;(3)复合型,共发育10处。(4)对滑坡稳定性影响因素进行研究,利用Geo Studio软件对不同因素影响下的滑坡渗流特征进行数值模拟,根据模拟结果并结合变形实例分别分析了不同类型滑坡的变形破坏的发育特征及变形机理。(5)建立定性评价方法以及定量评价方法,对前缘高程低于159m的动水压力型滑坡和复合型滑坡,利用定性评价和定量评价相结合的方法进行稳定性评价;对于前缘高程高于159m的滑坡以及浮托减重型滑坡,仅用定性评价方法进行稳定性评价。(6)以沙田滑坡为典型滑坡,进行综合评价。利用Geo Studio软件对沙田滑坡现有条件下以及增加库水位日降幅条件下的稳定性进行模拟分析,通过分析可知:沙田滑坡在库水位下降过程中由于坡体内外平衡被打破,产生渗流场变化以及应力重分布,导致在前缘消落带附近形成位移集中区,另外由于降雨作用导致滑坡后部陡坎处也出现位移集中区,变形破坏局部发育,不影响滑坡整体稳定性,所以沙田滑坡在现状条件下以及增加库水位日降幅条件下均处于整体基本稳定状态。(7)利用上述方法对研究区其他35处滑坡进行稳定性评价,从计算结果可以看出,在现状条件下区内滑坡共27处处于整体稳定状态,7处处于整体基本稳定状态,2处由于前缘强烈变形处于整体基本稳定局部欠稳定状态。在增加库水位日降幅条件下,共计14处滑坡稳定性有所降低,统计发现15处滑坡处于整体稳定状态,18处处于基本稳定状态,2处处于整体基本稳定局部欠稳定状态,1处处于整体基本稳定局部不稳定状态。
[Abstract]:The Three Gorges Reservoir area is a landslide area. With the reservoir storage, a large number of old landslides in the reservoir area are resurrected by different degrees of deformation. Increasing the daily decline of the reservoir water level will have a greater impact on the stability of the landslide. Therefore, it is necessary to carry out this study. The research area is located in the Fengdu County of Chongqing, the 434km of the Three Gorges Dam, the full length of 49km in the reservoir section, and the reservoir in the region. The landslide is widely distributed and poses a great threat to life and property, and there are 36 major landslides in its representative. Increasing the diurnal decline of the reservoir water level destroys the original balance state of the landslide and may lead to the resurrection of the landslides. The increase of the daily decline of the reservoir water level on the premise of ensuring the stability of the landslide will not cause the occurrence of the disaster, but also the reservoir can be improved. Therefore, it is of great practical significance to study the influence of the decline rate of the reservoir water level on the stability of the landslides in the area. In this paper, the Fengdu section of the Three Gorges Reservoir area is taken as the research object. On the basis of the geological environment conditions and the characteristics of the landslide development, the development law of the landslide in the study area is studied in detail, and the development law of the landslide is studied in detail. This paper classifies the landslides and studies the influencing factors and deformation mechanism of landslide stability. Finally, qualitative evaluation and quantitative evaluation are used to synthetically analyze the status of landslide stability and the stability prediction under the condition of increasing the diurnal decline of reservoir water level. After the previous study, the following results are obtained: (1) the landslides in the study area are developed in J2s, J3s, J3p strata, Lithology is mainly sandstone and mudstone, which can be divided into three types of engineering geological rock groups: I, hard and thick layered sandstone mainly; II, soft and hard layered sandstone, clay rock interbedding, and soft layered clay rock. The landslide deformation mode is mainly creep slip and crack type, slip and crack type, a little slip bending type. (2) landslides in the study area are in accordance with engineering field. According to the statistics of the rock group, there are 8 landslides in type I rock group, 13 landslides in class II rock group and 15 landslides in class III rock group, and there are also differences in the material composition of the landslides developed in different engineering geological groups. Corresponding to the classification of engineering rock groups, the accumulation bodies are divided into three categories: I. Soil clip rock block stone; II, silty clay fragment stone + front slope table accumulated Sawa Shi; III, silty clay mainly, mudstone fragment stone. (3) the landslides in the area are divided into three categories according to the effect of reservoir water: (1) the dynamic water pressure type, the total development of 23 places; (2) floating relief, 3; (3) composite type, altogether 10. (4) on the stability of landslide stability factors The characteristics of landslide seepage under the influence of different factors are simulated by Geo Studio software. The development characteristics and deformation mechanism of different types of landslides are analyzed according to the simulation results and combined with the deformation cases. (5) the qualitative evaluation method is established and the quantitative evaluation method is established, and the height of the front edge is lower than that of 159M. The stability evaluation of dynamic water pressure landslides and compound landslides with qualitative evaluation and quantitative evaluation is carried out by qualitative evaluation and quantitative evaluation. Stability evaluation is carried out only by qualitative evaluation method. (6) comprehensive evaluation is carried out by using Sha Tin landslide as a typical landslide. (6) Geo Studio software is used. The stability of Sha Tian landslide under the existing conditions and the daily decline of the reservoir water level is simulated and analyzed. Through the analysis, it can be seen that, in the process of the decline of the reservoir water level, the landslide caused the change of the seepage field and the stress redistribution, resulting in the formation of the displacement concentration area near the front edge of the falling zone. The rainfall effect leads to the displacement concentration area in the steep ridge of the back of the landslide, and the deformation damage is partially developed and does not affect the overall stability of the landslide. Therefore, the Shatin landslide is in the whole basic stable state under the condition of the present condition and the increase of the diurnal decline of the reservoir water level. (7) the stability evaluation of the other 35 landslides in the study area is carried out by the above method. According to the calculation results, we can see that 27 landslides in the present condition are in the whole stable state, 7 are in the whole basic stable state, and the 2 places are in the whole basic stable partial stable state because of the strong deformation of the front edge. Under the condition of increasing the diurnal decline of the reservoir water level, the stability of the 14 landslides is reduced, and 15 statistics are found. The landslide is in the whole stable state, 18 places are in the basic stable state, 2 are in the whole basic stable local under stable state, and 1 are in the whole stable and local unstable state.
【学位授予单位】：成都理工大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：P642.22

【参考文献】