马吉高拱坝右岸坝肩岩体三维结构分析
发布时间：2018-09-01 18:40
【摘要】：拟建的怒江马吉高拱坝，设计坝高300m，装机容量4200MW，为世界级高坝。拱坝的稳定性主要靠坝肩岩体来承担，坝肩岩体的均一性、承载能力以及稳定性直接关系着拱坝的安全。坝肩岩体结构特征控制着坝肩岩体的变形、破坏机制、力学性质以及坝肩抗力体块体边界构成，进而决定着拱坝的稳定性。因此对马吉高拱坝两岸坝肩岩体结构特征进行研究，对整个工程的可行性、安全性及经济性意义重大。 本文以“岩体结构控制论”为主要指导思想，以右岸一条测线为例，对拱坝安全稳定所关注的右岸坝肩岩体结构进行了研究，探索了一种利用地质建模软件从三维角度表征岩体结构的新方法。通过本文的深入研究，得到了如下几点结论： （1）研究了马吉水电站木加甲坝址的工程地质条件，认为坝址区属于贡山—福贡弧缘褶皱带内的丙中洛褶皱束范畴，区域构造不发育，无深大断裂及活断层发育，不具备发生6.5级以上强震的构造条件，新构造运动主要表现为区域性上升运动；坝区属高山峡谷地貌，两岸岸坡基本对称，地形完整，岩性主要为混合花岗岩、混合片麻岩，岩石坚硬，岩体完整，岩层陡倾，适合修建拱坝。 （2）坝区内结构面发育，主要包括断层、挤压带（面）、剪切带、节理裂隙等。右岸无I，II级结构面，III、IV级断层按走向分为SE150°、SW229°和SW252°三组，延伸长度都在多在200m左右，破碎带宽度平均0.25m，组成物质以岩屑岩块为主少量夹泥，性质以张扭和压扭为主，都为陡倾角。V级结构面为随机裂隙，，裂隙倾角以陡倾为主，中等倾角次之，缓倾角裂隙亦见有发育。根据优势方向划分了4组，裂隙性状较好，多为刚性或着次硬性结构面。 （3）根据规范并引入地震纵波速，RQD，和节理间距三个量化指标对马吉水电站右岸坝肩岩体进行了风化带划分，并利用蒙特卡罗方法按风化段进行了三维裂隙网络模拟。 （4）利用三维地质建模软件对地形面、岩层、岩脉包体、风化面、确定性的断层、模拟出的裂隙以1:1000的比例进行了三维地质建模，创新性地提出了利用商业化软件建立岩体结构模型的新方法，该方法具有较强的推广性。 （5）在岩体结构三维表征的基础上，对组成岩体结构的结构面和结构体进行了研究：裂隙具有上陡下缓的发育规律，裂隙间距整体上呈现出随硐深增加、高程增加而变大的规律，裂隙迹长多服从伽玛分布；岩体内裂隙相互切割形成的孤立块体较少，提取边长为2m的岩体单元进行研究，发现块体单元归纳起来主要有板片状，条柱状，棱锥状，棱柱状和复杂形状，棱锥状块体比例最大，板片状和棱柱状次之。强风化岩体属于碎裂结构到块裂结构，弱风化上带岩体属于块裂结构和镶嵌结构，弱风化下带岩体为互层状结构到中厚层状结构，微风化岩体为厚层状结构或块状结构，新鲜岩体属于巨厚层状结构或整体块状结构。裂隙切割构成的岩体结构较小，控制着岩体的力学性质，难以形成影响坝肩稳定的边界条件。 （6）通过透视地形面，对断层系统切割形成的宏观岩体结构进行了研究，坝肩岩体被断层切割成了巨大的柱状和层状，与连通率最高达55.8%的缓倾坡外的裂隙共同控制着坝肩的稳定性。结合拱坝推力方向，分析了坝肩抗力体的边界条件，提取了底滑面和侧裂面，利用三维结构模型搜索出了6个潜在滑移块体，并对其进行了表达，为将来进行坝肩稳定性评价奠定了基础。
[Abstract]:The proposed Maji high arch dam on Nujiang River is a world-class high dam with a design height of 300m and a installed capacity of 4200MW. The stability of the dam is mainly assumed by the abutment rock mass. The homogeneity, bearing capacity and stability of the abutment rock mass are directly related to the safety of the arch dam. The structural characteristics of the abutment rock mass control the deformation, failure mechanism and mechanical properties of the abutment rock mass. The stability of the arch dam is determined by the composition of the abutment resistance block boundary. Therefore, it is of great significance for the feasibility, safety and economy of the whole project to study the structural characteristics of the abutment rock mass on both sides of the Maji high arch dam.
Based on the principle of "rock mass structure cybernetics", taking a survey line on the right bank as an example, this paper studies the rock mass structure of the abutment on the right bank, which is concerned about the safety and stability of arch dams, and explores a new method to characterize the rock mass structure from a three-dimensional perspective by using geological modeling software. :
(1) The engineering geological conditions of Mujiajiajia dam site of Maji Hydropower Station are studied. It is considered that the dam site area belongs to the category of Bingzhongluo fold bundle in the Gongshan-Fugong arc margin fold belt. The regional structure is undeveloped, there are no deep and large faults and active faults, and there is no structural condition for strong earthquakes with magnitude 6.5 or above. The neotectonic movement is mainly manifested by regional ascending movement. The dam area is a high mountain and Canyon landform, the banks of both sides are basically symmetrical, the topography is complete, the lithology is mainly mixed granite, mixed gneiss, rock hard, rock integrity, rock stratum steep inclination, suitable for the construction of arch dam.
(2) Structural planes are developed in the dam area, mainly including faults, compression zones (planes), shear zones, joints and cracks. There are no I, II structural planes on the right bank, and III, IV faults are divided into three groups according to strike: SE150 degree, SW229 degree and SW252 degree. The extensional length is more than 200 m, and the average width of fracture is 0.25 M. The V-class structural plane is random fracture, the inclination angle of fracture is steep, the middle inclination angle is secondary, and the gentle inclination fracture is also developed.
(3) The weathering zones of the abutment rock mass on the right bank of Maji Hydropower Station are divided according to the code and the seismic P-wave velocity, RQD and joint spacing are introduced, and the three-dimensional fracture network simulation is carried out according to the weathering section by Monte Carlo method.
(4) Three-dimensional geological modeling of topographic surface, rock strata, dike inclusions, weathering surface, deterministic faults and simulated fissures is carried out in a ratio of 1:1000 by using three-dimensional geological modeling software, and a new method of establishing rock mass structural model by using commercial software is innovatively put forward, which has strong generalization.
(5) On the basis of the three-dimensional characterization of rock mass structure, the structural planes and bodies of rock mass structure are studied. Cracks have the regularity of developing up steeply and down slowly. The spacing of cracks on the whole shows the regularity of increasing with the increase of cave depth and elevation, and the crack trace length mostly obeys gamma distribution. It is found that the block units are mainly plate-like, strip-like, pyramid-like, prism-like and complex shapes, with the largest proportion of pyramid-like blocks, followed by plate-like and prism-like ones. And mosaic structure, the rock mass in the weak weathering zone is interbedded structure to medium-thick bedded structure, the slightly weathered rock mass is thick bedded structure or block structure, and the fresh rock mass is huge thick bedded structure or block structure. Pieces.
(6) Macroscopic rock mass structure formed by cutting fault system is studied through perspective topography. The abutment rock mass is cut into huge columns and layers by the fault, and the stability of the abutment is controlled by the cracks outside the gentle slope with the highest connectivity of 55.8%. Taking the bottom sliding surface and the side crack surface, six potential sliding blocks are searched out by using the three-dimensional structural model and expressed, which lays a foundation for the stability evaluation of the abutment in the future.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TV223;TV642.4
本文编号：2218022
[Abstract]:The proposed Maji high arch dam on Nujiang River is a world-class high dam with a design height of 300m and a installed capacity of 4200MW. The stability of the dam is mainly assumed by the abutment rock mass. The homogeneity, bearing capacity and stability of the abutment rock mass are directly related to the safety of the arch dam. The structural characteristics of the abutment rock mass control the deformation, failure mechanism and mechanical properties of the abutment rock mass. The stability of the arch dam is determined by the composition of the abutment resistance block boundary. Therefore, it is of great significance for the feasibility, safety and economy of the whole project to study the structural characteristics of the abutment rock mass on both sides of the Maji high arch dam.
Based on the principle of "rock mass structure cybernetics", taking a survey line on the right bank as an example, this paper studies the rock mass structure of the abutment on the right bank, which is concerned about the safety and stability of arch dams, and explores a new method to characterize the rock mass structure from a three-dimensional perspective by using geological modeling software. :
(1) The engineering geological conditions of Mujiajiajia dam site of Maji Hydropower Station are studied. It is considered that the dam site area belongs to the category of Bingzhongluo fold bundle in the Gongshan-Fugong arc margin fold belt. The regional structure is undeveloped, there are no deep and large faults and active faults, and there is no structural condition for strong earthquakes with magnitude 6.5 or above. The neotectonic movement is mainly manifested by regional ascending movement. The dam area is a high mountain and Canyon landform, the banks of both sides are basically symmetrical, the topography is complete, the lithology is mainly mixed granite, mixed gneiss, rock hard, rock integrity, rock stratum steep inclination, suitable for the construction of arch dam.
(2) Structural planes are developed in the dam area, mainly including faults, compression zones (planes), shear zones, joints and cracks. There are no I, II structural planes on the right bank, and III, IV faults are divided into three groups according to strike: SE150 degree, SW229 degree and SW252 degree. The extensional length is more than 200 m, and the average width of fracture is 0.25 M. The V-class structural plane is random fracture, the inclination angle of fracture is steep, the middle inclination angle is secondary, and the gentle inclination fracture is also developed.
(3) The weathering zones of the abutment rock mass on the right bank of Maji Hydropower Station are divided according to the code and the seismic P-wave velocity, RQD and joint spacing are introduced, and the three-dimensional fracture network simulation is carried out according to the weathering section by Monte Carlo method.
(4) Three-dimensional geological modeling of topographic surface, rock strata, dike inclusions, weathering surface, deterministic faults and simulated fissures is carried out in a ratio of 1:1000 by using three-dimensional geological modeling software, and a new method of establishing rock mass structural model by using commercial software is innovatively put forward, which has strong generalization.
(5) On the basis of the three-dimensional characterization of rock mass structure, the structural planes and bodies of rock mass structure are studied. Cracks have the regularity of developing up steeply and down slowly. The spacing of cracks on the whole shows the regularity of increasing with the increase of cave depth and elevation, and the crack trace length mostly obeys gamma distribution. It is found that the block units are mainly plate-like, strip-like, pyramid-like, prism-like and complex shapes, with the largest proportion of pyramid-like blocks, followed by plate-like and prism-like ones. And mosaic structure, the rock mass in the weak weathering zone is interbedded structure to medium-thick bedded structure, the slightly weathered rock mass is thick bedded structure or block structure, and the fresh rock mass is huge thick bedded structure or block structure. Pieces.
(6) Macroscopic rock mass structure formed by cutting fault system is studied through perspective topography. The abutment rock mass is cut into huge columns and layers by the fault, and the stability of the abutment is controlled by the cracks outside the gentle slope with the highest connectivity of 55.8%. Taking the bottom sliding surface and the side crack surface, six potential sliding blocks are searched out by using the three-dimensional structural model and expressed, which lays a foundation for the stability evaluation of the abutment in the future.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TV223;TV642.4
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本文编号：2218022
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