金沙江旭龙坝址区左岸高陡斜坡岩体结构特征及稳定性初探

发布时间：2018-03-14 06:23

本文选题：高陡斜坡　切入点：岩体结构　出处：《成都理工大学》2014年硕士论文　论文类型：学位论文

【摘要】：拟建的旭龙水电工程位于云南省德钦县与四川省得荣县交界的金沙江上，大坝为213m混凝土双曲拱坝。旭龙坝址区所在金沙江河段谷坡高陡，规模巨大，坝区岩体经历了长期的地质作用，结构面发育，岩体结构特征复杂，结构面的相互交接可能引起斜坡的变形失稳，影响工程计划的顺利进行和安全运营。在工程开挖施工以后，左岸将形成坝肩高边坡，开挖规模大，形成的工程边坡高陡，一旦失稳，即使是小规模的块体，都会造成严重的后果。本文以金沙江旭龙水电站坝址区左岸高陡斜坡为研究对象，在对坝址区基本地质条件调查的基础上，对坝址区左岸斜坡的岩体结构面特征、斜坡岩体变形破坏模式和岩体质量分级进行了系统研究，最后运用FLAC、SASW等数值程序对斜坡的整体稳定性和局部块体稳定性进行了分析和研究，主要取得以下几点认识和结论：（1）坝址区主要出露印支期灰白色中细粒花岗岩（γ5）、中元古界雄松群三段的灰黑色-暗绿色斜长角闪片岩（Pt2x3），以及印支期对斜长角闪片岩混合变质作用形成的混合岩。研究区大地构造演化历史悠久，构造作用复杂，把左岸分为四个构造分区进行研究；（2）研究区断层类结构面主要为Ⅲ、Ⅳ级，且多与岸坡走向大角度相交；Ⅱ级结构面仅发育F1、F2两条；通过对坝址区各级结构面和各分区结构面分析可以发现，坝址区大部分结构面与金沙江岸坡呈小角度相交，各分区的优势结构面方位均不相同，且大部分为中陡倾角，缓倾角较少。（3）根据对坝址区左岸斜坡进行的分区、分高程的变形破坏迹象调查，结合斜坡的岩体结构特性，进行变形破坏模式分析，提出了4种左岸斜坡岩体的变形破坏模式。（4）运用岩体质量分级的RMR法和CSMR法对左岸斜坡的岩体质量进行初步分级，，然后结合现场地质分类，考虑各种方法的权重，综合得出各级岩体质量的界线。分级结果表明各个高程上的岩体基本顺河呈带状分布，向山内依次为Ⅳ、Ⅲ、Ⅱ类岩体，而且Ⅳ类岩体随着高程的上升深度随之加深。CSMR岩体质量分级法所得的结果表明，斜坡浅表层的稳定性一般，只有局部位置的稳定性差。（5）运用二维有限差分数值模拟软件FLAC2D，考虑斜坡岩体的卸荷特征，对斜坡的整体稳定性进行模拟研究。基于莫尔—库仑准则并利用强度折减法得出的左岸斜坡稳定系数表明斜坡整体稳定，但是斜坡中高程的表层岩体的稳定性较差。然后运用SASW数值程序对斜坡局部块体稳定性的模拟研究表明，斜坡上各种结构面可能组成的最大规模的块体，稳定块体较多，没有大范围的块体失稳现象，但是斜坡表面的局部位置还是存在着小规模的不稳定块体。在以后斜坡的施工过程中应注意不同部位的块体的稳定情况，必要时应当采取适当的工程保护措施防止其失稳。
[Abstract]:Asahi Liuzhou hydropower project is located at the junction of the Derong County of Yunnan province Deqin County of Sichuan province and the Jinsha River, the dam is 213M concrete hyperbolic arch dam. The dam area of Jinsha River Asahi Dragon Valley High and steep slope section, huge rock has experienced a long period of geological processes, structure development, rock mass structure characteristics of complex structure. The interactions may cause the slope deformation and instability, affecting the project smooth and safe operation. After the engineering excavation, dam abutment high slope on the left bank of the formation, the formation of large-scale excavation engineering of high steep slope, once the instability, even a small scale, it will cause serious consequences.
Taking the Jiang Xulong hydropower station dam site on the left bank of the high and steep slope as the research object, based on the investigation of the basic geological conditions in the dam area, rock structure in the dam area on the left bank slope characteristics, failure mode and the classification of rock mass are studied of slope deformation, finally using FLAC, overall stability of the slopes of SASW etc. the numerical procedure and local block stability analysis and research, mainly obtains the following conclusions:
(1) the dam area mainly exposed Indosinian gray fine-grained granite (gamma 5), Middle Proterozoic group three black male pine - dark green amphibolite schist (Pt2x3), and the Indosinian mixing amphibolite schist metamorphism to form mixed plagioclase. The tectonic evolution history of the study area a long, complex structure, the left bank is divided into four tectonic zoning research;
(2) the study area fault structure plane is mainly III, IV, and large angle and slope toward the intersection; II structure only developed F1, F2 two; the structures of dam area surface and each partition structure analysis can be found, most of the structure in dam area of Jinsha River surface and the slope is small the angle between the surface structure of each partition, advantages range are not the same, and most of them are in steep dip, dip angle is less.
(3) according to the zoning of the left bank slope of dam site, the investigation of deformation and failure at different height, combined with the characteristics of rock mass structure of slope, the deformation failure mode is analyzed, and 4 kinds of deformation and failure modes of the left bank slope rock are put forward.
(4) the use of rock mass quality classification method and RMR CSMR method on the left bank slope rock mass quality of the initial classification, then combined with the geological classification, considering the weight of various methods, and concluded that the boundaries of rock quality classification. All results show that all the basic rock elevation along the river zonal distribution, to Yamauchi Yoji IV, III class II, and class IV rock, rock mass increase with the elevation of the depth deepened the.CSMR rock mass classification method. The results show that the stability of shallow slope stability in general, only the local position of the poor.
(5) using two-dimensional finite difference numerical simulation software FLAC2D, considering the characteristics of unloading rock slope, simulation of the whole stability of the slope. The left bank slope stability coefficient of Mohr Coulomb criterion and by using strength reduction method show that the overall stability of slope based on, but is the poor stability of rock slopes in surface elevation. Then use of SASW numerical simulation program for the slope local block stability showed that the surface structure on the slope might constitute the largest block, more stable block, block there is no large-scale instability, but the local position of the surface of the slope or the existence of unstable blocks should pay attention to small scale. Block stability in different parts of the construction process after the slope, when necessary, should take appropriate protective measures to prevent the engineering instability.

【学位授予单位】：成都理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TV223

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