快速隆升怒江河段松塔水电站坝肩岩体结构特征及质量空间分区研究

发布时间：2018-05-17 22:24

本文选题：青藏高原隆升 + 河谷快速下切　；参考：《吉林大学》2016年博士论文

【摘要】：自第四纪更新世以来,青藏高原发生间歇性快速隆升,怒江河谷随之发生间歇性快速下切,形成了典型的怒江峡谷地貌。拟建的松塔水电站正位于怒江上游峡谷河段。黑云二长花岗岩是坝址区出露的主要岩性,在典型河谷高边坡应力场的作用下,其内部形成大量的中缓倾坡外裂隙,对坝肩边坡稳定性极其不利。因此,有必要对松塔水电站坝址区的岩体结构展开研究。基于“岩体结构控制论”的思想,本文对河谷高边坡的岩体结构特征进行了重点论述。以精细的结构面描述和详实的地质资料为基础,总结了怒江松塔坝址区中缓倾坡外结构面的空间组合模式,从怒江河谷间歇性快速下切过程中岸坡应力场变化的角度初步阐述了中缓倾坡外结构面的成因机制。由于谷坡裂隙岩体参数存在不确定性,重点对岩体参数的空间效应与尺寸效应进行了研究。在消除造成岩体参数不确定性的原因后,对坝肩岩体质量进行了空间分区,为工程确定合理的建基面提供了依据。通过以上系统的研究,主要得到以下结论:1.以详实的结构面调查资料为基础,从结构面的工程地质性状以及意义出发,对怒江松塔坝址区揭露的结构面进行了系统的分级分类。并重点研究了中缓倾坡外结构面的空间组合模式,其倾角总体上表现为“下缓上陡”、“外缓内陡”的特征,其发育密度总体上表现为“外密内疏”的特征。通过成因机制分析,认为中缓倾坡外结构面形成时的力学模式是由河谷下切过程中岸坡应力集中与应力调整造成的。受青藏高原间歇性快速隆升的影响,怒江河谷经历“快速下切→相对稳定→快速下切→相对稳定”的交替过程。正是该过程中产生的不同程度的应力集中和不匀速的应力调整,使岸坡中发育有裂隙相对密集带和相对稀疏带。2.岩体物理力学参数存在较强的空间效应,只有找出具有相似结构岩体的边界,才能对工程岩体建立合理的物理或数值模型。考虑到裂隙产状和迹长大小是影响复杂裂隙岩体结构特征的重要参数,基于游程检验的方法,本文提出了一种考虑裂隙产状与迹长的相似性来划分岩体结构统计均质区的方法。最后,利用该方法对松塔水电站右岸坝肩岩体进行了岩体结构统计均质区的划分。3.在对右岸坝肩岩体中发育的裂隙进行全面调查、精细描述的前提下,对位于各个统计均质区域内裂隙的张开度、粗糙度、地下水状况、风化与蚀变状况进行了统计与分析,获得了裂隙状态的空间发育特征:(1)右岸坝肩岩体中裂隙主要呈紧闭状态,但卸荷段岩体中紧闭型裂隙所占的比例小于卸荷调整段,而卸荷调整段岩体中紧闭型裂隙所占的比例小于原岩段;(2)卸荷段岩体中裂隙表面较平直,原岩段岩体中裂隙表面起伏较大,卸荷调整段岩体中裂隙表面形态介于两者之间;(3)卸荷段岩体中裂隙地下水状况以潮湿~浸水为主,原岩段岩体中裂隙地下水状况以干燥为主,卸荷调整段岩体中裂隙地下水状况介于两者之间;(4)卸荷段岩体中裂隙的风化与蚀变程度强于卸荷调整段,而卸荷调整段岩体中裂隙的风化与蚀变程度强于原岩段。4.基于每个统计均质区内裂隙的发育规律,对各个均质区岩体建立了三维裂隙网络模型,并采用投影法计算了裂隙三维连通率。最后,获得了中缓倾裂隙(底滑面)连通率的空间变化规律:(1)在水平深度(硐深)方向上,三维连通率的大小基本呈现出“外大内小”的趋势,取得最大连通率时对应的最佳理想截面的倾角呈现出“外缓内陡”的趋势;(2)在不同高程上,最佳理想截面的倾角呈现出“下缓上陡”的趋势。5.同一均质区域内岩体参数还存在着尺寸效应,只有确定表征单元体的大小,才能为工程岩体进行宏观力学计算提供合理参数。考虑到裂隙三维连通率是由岩体中裂隙的多个几何参数决定的用来反映岩体力学性质的参数,本文基于裂隙三维连通率的尺寸效应,提出了一种新的确定表征单元体尺寸的方法。最后,系统地研究了表征单元体尺寸与裂隙直径、空间密度、产状之间的关系,并首次建立了它们之间的函数关系。6.岩体质量评价有助于选取合理的岩体力学参数,在消除岩体参数的不确定性(空间效应与尺寸效应)后,为充分考虑复杂岩体结构的空间特征,将岩体结构三维网络模型中的多个空间指标引入到岩体质量评价中,建立了一种新的岩体质量评价模型,并利用该方法对不同均质区的岩体质量空间分区进行了研究。
[Abstract]:Since the Pleistocene in the Quaternary, the Qinghai Xizang Plateau has been intermittently rapid uplift, and the Nu River Valley has been intermittently cut down rapidly, and the typical Nu River Canyon landforms are formed. The proposed song Tak hydropower station is located in the canyon section of the upper reaches of Nu River. The black cloud two granite is the main lithology in the dam site, and the high slope stress field in the typical Valley As a result, it is necessary to study the rock mass structure of the dam site area of the pine tower hydropower station. Based on the theory of "rock mass structure control", this paper focuses on the rock mass structure characteristics of the high slope of the river valley. On the basis of descriptive and detailed geological data, the spatial combination pattern of the gently tilted slope in the Nu River tower dam site is summarized. From the angle of the change of the bank slope stress field during the intermittent rapid cutting process of the Nu River Valley, the formation mechanism of the medium slope outside the slope is preliminarily expounded. The space effect and size effect of rock mass parameters are studied. After eliminating the cause of the uncertainty of rock mass parameters, the spatial partition of the mass of the abutment rock mass is carried out, which provides the basis for the determination of the reasonable construction base. Through the study of the above system, the following conclusions are obtained: 1. the detailed data of structural surface investigation is given. Based on the engineering geological characteristics and significance of the structural plane, the structure surface of the Nu River pine tower dam site is classified and classified systematically, and the spatial combination pattern of the moderately gently tilting slope is mainly studied. The dip angle is characterized by the characteristics of "slow down and steep" and "gentle inside steepness", and its development density is generally on the table. Through the analysis of the genetic mechanism, it is believed that the mechanical model of the formation of the gentle slope outside the slope is caused by the stress concentration and stress adjustment of the bank slope during the valley cutting process. The Nu River Valley experienced the rapid downward cutting, relative stability, rapid downward cutting and phase, influenced by the intermittent rapid uplift of the Qinghai Tibet Plateau. It is the alternation process of stability ". It is the different degree of stress concentration and uneven stress adjustment produced in this process, so that there is a strong spatial effect on the physical and mechanical parameters of.2. rock mass with relative dense zone and relative sparse zone in the bank slope. Only by finding the boundary of rock with similar structure can the rock mass be established. A reasonable physical or numerical model. Considering that the shape and length of cracks are important parameters affecting the structural characteristics of complex fractured rock mass, based on the method of range test, this paper presents a method for dividing the statistical homogeneous area of rock mass structure into consideration of the similarity of fracture and trace length. Finally, the method is used to the right of the tower of the pine tower hydropower station. The rock mass statistical homogeneous area of the abutment rock mass is divided into.3. to investigate the fracture in the right bank abutment rock mass. On the premise of fine description, the crack opening, roughness, groundwater condition, weathering and alteration conditions are analyzed and analyzed, and the fracture state is obtained. The characteristics of spatial development are as follows: (1) the fracture of the rock mass in the right bank abutment is mainly closed, but the proportion of the closed fracture in the rock mass is less than the unloading adjustment section, and the proportion of the closed fracture in the rock mass is less than that of the original rock. (2) the fracture surface in the unloading section is more straight, and the fracture surface in the rock mass is undulating. The fracture surface morphology of the rock mass in the unloading adjustment section is between the two. (3) the fractured groundwater situation in the rock mass of the unloading section is mainly moist ~ soaked, and the fractured groundwater situation in the rock mass is mainly dry, and the fractured groundwater in the rock mass of the unloading adjustment section is between the two; (4) the weathering and alteration of the fracture in the unloading section rock mass. The degree is stronger than the unloading adjustment section, and the weathering and alteration of the rock mass in the rock mass is stronger than that in the original rock section.4., which is based on the law of fracture development in each statistical homogeneous area. A three-dimensional fracture network model is established for the rock mass in each homogeneous area, and the three dimensional connectivity of the fracture is calculated by the projection method. Finally, the medium dip fracture (bottom) is obtained. The spatial variation of the connectivity rate is: (1) in the direction of the horizontal depth (depth), the size of the three-dimensional connectivity is basically the trend of "big inside and small outside", and the inclination of the best ideal cross section corresponding to the maximum connectivity shows a trend of "slow inside steepness"; (2) the inclination of the best ideal cross section appears at different heights. There is also a size effect in the rock mass parameters in the same homogeneous region. Only to determine the size of the characterization unit body can provide reasonable parameters for the macroscopic mechanical calculation of the engineering rock mass. Considering that the three-dimensional connectivity of the fracture is determined by several parameters of the fracture in the rock mass, it can be used to reflect the mechanical properties of the rock mass. In this paper, based on the size effect of the fracture three-dimensional connectivity, a new method for determining the size of the body is proposed. Finally, the relationship between the size of the body and the diameter of the fracture, the spatial density and the shape of the unit is systematically studied. The.6. rock mass evaluation is helpful for the first time. In order to eliminate the uncertainty of rock mass parameters (space effect and size effect), the mechanical parameters of rock mass are taken into consideration of the spatial characteristics of complex rock mass structure. A new rock mass quality evaluation model is established by introducing multiple spatial indexes in the 3D network model of rock mass structure, and a new rock mass quality evaluation model is established, and the method is used for the rock mass quality evaluation. The spatial partition of rock mass in different homogeneous areas is studied.
【学位授予单位】：吉林大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TV223

【相似文献】