金沙江某水电站岸坡深部变形破裂成因分析
发布时间：2018-07-16 23:50
【摘要】：金沙江某水电站坝址区岸坡常规风化卸荷带以里的深部新鲜岩体内发育有一系列的变形破裂现象，与西南地区其他水电站岸坡已揭露的深部裂缝现象存在明显的差异，成为制约工程勘察、设计、施工和运营的重大工程地质问题。研究坝址区深部变形破裂的基本特征、揭示其成因机制，具有十分重要的理论价值和现实意义。 本文以坝址区岸坡深部变形破裂为研究对象，在查明深部变形破裂所处的地质环境背景及河谷演化模式的基础上，结合现场的地应力实测资料，通过对河谷应力场进行三维数值模拟反演，研究坝址区河谷应力场的演化特征，探讨深部变形破裂形成演化的宏观地应力背景。忠实于地质原型，详细分析深部变形破裂的现场地质描述，提取共性特征，进而将深部变形破裂分为三类。总结归纳深部变形破裂的发育分布规律和变形破坏特征，建立深部变形破裂的地质力学“概念模型”。在此基础上，以浅生时效改造理论为基础，采用地质过程机制分析方法，结合岩石力学、构造地质学等知识，初步揭示深部变形破裂的成因机制。本文主要取得的研究成果如下： （1）深入分析归纳深部变形破裂的地质描述，提取表观特征间的共性，将坝址区出露的深部变形破裂分为三类：微张型、中度松弛型和强烈松弛型。 （2）岸坡浅表部岩体在左岸倾NW向结构面发育，右岸倾SE向结构面发育，且均以中等倾角产出。岸坡浅表部结构面发育受河谷下切侧向卸荷回弹作用明显，平行于岸坡倾向坡外的结构面发育，结构面倾角与坡面倾角基本一致。深部岩体结构面除了具备浅部岩体结构面特征外，还发育有NE/NW和NE/SE向陡倾角结构面，形成一对陡倾角的共轭结构面体系。 （3）深部变形破裂除PD29、PD01、PD10均有出露。总体上高程越大，深部变形破裂发育程度越高。微张型深部变形破裂在左岸出露的平硐较右岸多，但两岸发育的数量相差不大，两岸发育数量随高程增高而增加。中度松弛型深部变形破裂在左岸10个平硐出露，在右岸只在2个平硐中出露，左岸总共68条，右岸发育10条，中高程最多，高程程最少。强烈松弛型深部变形破裂左岸在3个平硐内出露，发育20条；右岸在7个平硐中出露，发育48条，总体发育在高高程，低、中高程发育较少。两岸深部变形破裂集中发育的空间位置大致相同，主要集中在水平深度60-150m、垂直深度60-180m的空间范围内。 （4）两岸深部变形破裂总体上为NNE/NW方向，其中一组为中等倾角，另一组为陡倾角。其中，左岸优势方向为NNE/NW，大致与坡面平行，一组为中等倾角，另一组为陡倾角，83°倾角最为发育。右岸优势方向在NS/E~NNE/SE之间，以中陡倾角为主，大致平行与坡面。 （5）根据深部变形破裂的基本特征建立每类深部变形破裂的概念模型，结合坝址区的地应力演化特征，初步推断深部变形破裂形成的宏观机制为： 在NEE向最大主应力以及河谷下切岸坡岩体卸荷回弹变形的共同作用下，岸坡岩体能量剧烈释放，当释放的能量高于岸坡深部岩体中发育的NE向的两组共轭节理裂隙的强度时，节理裂隙赋存的深部微新岩体在近于轴向压力的作用下，发生继承性的张性破裂，，破裂面优势方向在最大主应力和河谷走向之间，共轭节理在两岸分别发育倾坡外的一组（左岸NE/NW发育，右岸NE/SE发育），其中： ①微张型：深部岩体在张破裂形成后，由于坝址区岸坡为山脊-冲沟相间地貌，而冲沟具有汇水的作用，汇聚的地表水沿着节理利裂隙深入坡体内。位于冲沟下方坡体内的深部变形破裂最易遭受下渗的地下水的风化侵蚀，故岩体风化锈染程度较大。分析表明，微张型深部变形破裂均位于冲沟下方的破体内。 根据格里菲斯裂纹扩展准则，坡体内NEE向的结构面与最大主应力方向近于平行或夹角很小，远小于裂纹的破裂角，故NEE向的结构面并不处于最有利于裂纹扩展的环境，所以微张型深部变形破裂的张开宽度很小。 ②中度松弛性：对于与最大主应力方向斜交的NE向节理裂隙，除了受到压致张破裂外，由于局部应力场及微地貌临空卸荷条件的差异，还会发生相对错动，产生剪切破坏。对于闭合较紧密或充填较密实岩块的结构面，充填的花岗岩岩块在剪切作用下破碎成“砂糖状”花岗岩岩屑，形成中度松弛型深部变形破裂。 根据格里菲斯裂纹扩展准则，坡体内NNE向的结构面以及四条仅EW向小断层与最大主应力方向夹角在30°左右，近似等于裂纹的破裂角，故NNE向的结构面处于最有利于裂纹扩展的方向，所以中度松弛型的张开宽度比微张型大。 ③强烈松弛型：断层或长达结构面附近岩体变形破坏程度更高，岩体块裂、碎裂化，结构面充填物松散，甚至局部架空，结构面受到挤压发生张性破坏后充填物大部分脱落，在剪切作用下结构面附近岩体进一步破坏脱落，形成强烈松弛型深部变形破裂。右岸高高程PD44、PD24所处的卸荷拉裂体最为发育。 （6）岸坡深部变形破裂是在河谷地貌形成演化过程中，伴随区域性剥蚀和河谷下切过程，岸坡构造应力场向自重应力场转化，深部节理裂隙优势方向与最大主应力以一定角度斜交时，在张剪应力环境下，产生的不同破坏程度的继生性的变形破裂。
[Abstract]:There are a series of deformation and rupture phenomena in the deep fresh rock mass in the slope of the dam site of a hydropower station in Jinsha River . There is a significant difference between the deep fractures exposed to the bank slope of other hydropower stations in Southwest China . It is a major engineering geological problem that restricts the investigation , design , construction and operation of the project . The basic characteristics of deep deformation and rupture in the dam site area are studied , the cause mechanism is revealed , and the important theoretical value and practical significance are disclosed .
Based on the analysis of the geological environment background and the river valley evolution model in the dam site area , based on the investigation of the geological environment background and the valley evolution model in the deep deformation fracture , the authors study the evolution characteristics of the stress field in the river valley area and discuss the macroscopic geostress background of the evolution of deep deformation rupture .
( 1 ) In - depth analysis of the geological description of deep deformation fracture , and extracting the commonness between apparent features , the deep deformation and rupture of the exposed deep deformation in the dam site area are divided into three types : microtension type , moderate relaxation type and intensive relaxation type .
( 2 ) The rock mass on the bank slope is developed on the left bank from the NW to the structural plane , and the right bank slope SE is developed on the structural plane . The structure surface developed by the lower cut side of the bank slope is obviously developed , and the inclination of the structural plane is basically the same as that of the slope surface .
( 3 ) Except PD29 , PD01 and PD10 in deep deformation , the higher the overall elevation , the higher the fracture development degree of deep deformation .
On the right bank , there are 48 out of seven flat chambers , 48 are developed , the overall development is at high elevation , low and medium elevation is less . The spatial position of the development of deep deformation and rupture of both sides is about the same , and is mainly concentrated in the space range of 60 - 150 m and vertical depth of 60 - 180m .
( 4 ) The fracture of deep deformation on both sides of the two sides is in the direction of NE / NW , one of which is medium dip and the other is steep .
( 5 ) Based on the basic features of deep deformation fracture , a conceptual model of deep deformation rupture is established . Combined with the geostress evolution characteristics of the dam site area , the macroscopic mechanism of deep deformation rupture is preliminarily deduced .
Under the joint action of the maximum principal stress and the unloading rebound deformation of the lower slope rock mass in the valley , the energy of the rock mass in the bank slope is strongly released . When the released energy is higher than the strength of the NE - directional two groups of conjugate joints developed in the deep rock mass in the bank slope , the deep micro - new rock mass with joint fissure is fractured , the dominant direction of the fracture surface is between the maximum main stress and the valley direction , and the conjugate joint is developed on the left bank NE / NW development and the right bank NE / SE respectively .
The results show that the deep deformation breakdown in the lower slope of the gully is the most vulnerable to the weathering erosion of the underground water . The analysis indicates that the deep deformation and rupture of the rock mass are located in the broken body under the gully .
According to the Griffiths crack propagation criterion , the structural plane in the direction of the slope body and the maximum principal stress direction are close to the parallel or included angle so as to be far smaller than the crack angle of the crack , so the circumferential structural plane is not in the environment which is favorable for crack propagation , so that the opening width of the micro - tension deep deformation fracture is small .
( 2 ) moderate relaxation : for NE - joints with oblique intersection with the maximum principal stress direction , in addition to being subjected to compression - induced rupture , relative error can occur due to the difference between local stress field and micro - geomorphic near - air unloading condition , and shear failure is generated .
According to the Griffiths crack propagation criterion , the structural plane in the longitudinal direction of the slope and four EW - trending small faults and the maximum principal stress direction are approximately equal to or less than 30 degrees , which is approximately equal to the crack angle of the crack , so that the structural plane in the trending direction is in the direction which is favorable for crack propagation , so that the opening width of the moderate relaxation type is larger than that of the microtension type .
( 3 ) The strong relaxation type : the deformation degree of the rock mass near the fault or the length of the structural plane is higher , the mass of the rock mass is cracked , fragmented , the structural plane filling is loose , and even the local overhead , the structural plane is subjected to the compressive deformation and the filling material mostly falls off , and the rock mass in the vicinity of the structural surface is further damaged and falls off under the shearing action , thereby forming a strong relaxation type deep deformation rupture .
( 6 ) The deep deformation and rupture of the bank slope is accompanied by regional erosion and valley cutting , along with the regional erosion and the valley cutting process , the stress field of the bank slope tectonic stress field is transformed to the dead weight , and the dominant direction of the deep joint fissure and the maximum principal stress are inclined at a certain angle .
【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
[Abstract]:There are a series of deformation and rupture phenomena in the deep fresh rock mass in the slope of the dam site of a hydropower station in Jinsha River . There is a significant difference between the deep fractures exposed to the bank slope of other hydropower stations in Southwest China . It is a major engineering geological problem that restricts the investigation , design , construction and operation of the project . The basic characteristics of deep deformation and rupture in the dam site area are studied , the cause mechanism is revealed , and the important theoretical value and practical significance are disclosed .
Based on the analysis of the geological environment background and the river valley evolution model in the dam site area , based on the investigation of the geological environment background and the valley evolution model in the deep deformation fracture , the authors study the evolution characteristics of the stress field in the river valley area and discuss the macroscopic geostress background of the evolution of deep deformation rupture .
( 1 ) In - depth analysis of the geological description of deep deformation fracture , and extracting the commonness between apparent features , the deep deformation and rupture of the exposed deep deformation in the dam site area are divided into three types : microtension type , moderate relaxation type and intensive relaxation type .
( 2 ) The rock mass on the bank slope is developed on the left bank from the NW to the structural plane , and the right bank slope SE is developed on the structural plane . The structure surface developed by the lower cut side of the bank slope is obviously developed , and the inclination of the structural plane is basically the same as that of the slope surface .
( 3 ) Except PD29 , PD01 and PD10 in deep deformation , the higher the overall elevation , the higher the fracture development degree of deep deformation .
On the right bank , there are 48 out of seven flat chambers , 48 are developed , the overall development is at high elevation , low and medium elevation is less . The spatial position of the development of deep deformation and rupture of both sides is about the same , and is mainly concentrated in the space range of 60 - 150 m and vertical depth of 60 - 180m .
( 4 ) The fracture of deep deformation on both sides of the two sides is in the direction of NE / NW , one of which is medium dip and the other is steep .
( 5 ) Based on the basic features of deep deformation fracture , a conceptual model of deep deformation rupture is established . Combined with the geostress evolution characteristics of the dam site area , the macroscopic mechanism of deep deformation rupture is preliminarily deduced .
Under the joint action of the maximum principal stress and the unloading rebound deformation of the lower slope rock mass in the valley , the energy of the rock mass in the bank slope is strongly released . When the released energy is higher than the strength of the NE - directional two groups of conjugate joints developed in the deep rock mass in the bank slope , the deep micro - new rock mass with joint fissure is fractured , the dominant direction of the fracture surface is between the maximum main stress and the valley direction , and the conjugate joint is developed on the left bank NE / NW development and the right bank NE / SE respectively .
The results show that the deep deformation breakdown in the lower slope of the gully is the most vulnerable to the weathering erosion of the underground water . The analysis indicates that the deep deformation and rupture of the rock mass are located in the broken body under the gully .
According to the Griffiths crack propagation criterion , the structural plane in the direction of the slope body and the maximum principal stress direction are close to the parallel or included angle so as to be far smaller than the crack angle of the crack , so the circumferential structural plane is not in the environment which is favorable for crack propagation , so that the opening width of the micro - tension deep deformation fracture is small .
( 2 ) moderate relaxation : for NE - joints with oblique intersection with the maximum principal stress direction , in addition to being subjected to compression - induced rupture , relative error can occur due to the difference between local stress field and micro - geomorphic near - air unloading condition , and shear failure is generated .
According to the Griffiths crack propagation criterion , the structural plane in the longitudinal direction of the slope and four EW - trending small faults and the maximum principal stress direction are approximately equal to or less than 30 degrees , which is approximately equal to the crack angle of the crack , so that the structural plane in the trending direction is in the direction which is favorable for crack propagation , so that the opening width of the moderate relaxation type is larger than that of the microtension type .
( 3 ) The strong relaxation type : the deformation degree of the rock mass near the fault or the length of the structural plane is higher , the mass of the rock mass is cracked , fragmented , the structural plane filling is loose , and even the local overhead , the structural plane is subjected to the compressive deformation and the filling material mostly falls off , and the rock mass in the vicinity of the structural surface is further damaged and falls off under the shearing action , thereby forming a strong relaxation type deep deformation rupture .
( 6 ) The deep deformation and rupture of the bank slope is accompanied by regional erosion and valley cutting , along with the regional erosion and the valley cutting process , the stress field of the bank slope tectonic stress field is transformed to the dead weight , and the dominant direction of the deep joint fissure and the maximum principal stress are inclined at a certain angle .
【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
【参考文献】
相关期刊论文 前10条
1 韩刚;赵其华;彭社琴;;白鹤滩水电站坝区岩体深部破裂特征及成因机制[J];吉林大学学报(地球科学版);2011年02期
2 严明;黄润秋;徐佩华;;某水电站坝前左岸高边坡深部破裂形成机制分析[J];成都理工大学学报(自然科学版);2005年06期
3 王瑜;赵其华;;某电站坝区左岸深部裂缝特征及成因机理浅析[J];长江科学院院报;2010年04期
4 王思敬;地球内外动力耦合作用与重大地质灾害的成因初探[J];工程地质学报;2002年02期
5 王兰生;李文纲;孙云志;;岩体卸荷与水电工程[J];工程地质学报;2008年02期
6 谭成轩;张鹏;郑汉淮;孙炜锋;王继明;孙叶;;雅砻江锦屏一级水电站坝址区实测地应力与重大工程地质问题分析[J];工程地质学报;2008年02期
7 李愿军;;深部裂缝带——一种新的地震构造样式[J];中国工程科学;2006年04期
8 李s
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