【作者】 柴波；

【导师】 殷坤龙；

【作者基本信息】 中国地质大学 ， 岩土工程， 2008， 博士

【摘要】 岩体是在漫长的地质历史时期内经历了多次反复的地质作用,经受过变形、破坏,形成了一定岩石成分和结构,并赋存于一定地质环境中的特殊结构体。“岩体结构控制论”认为岩体结构不仅能反映岩体的构造演化历史,同时控制着岩体的变形破坏特征,论文正是基于以上两点思想,开展了巴东新城区库岸斜坡岩体结构的系统研究。巴东县新城区是三峡库区地质条件最复杂的城区之一,发育有黄土坡滑坡、赵树岭滑坡、太矶头滑坡、童家坪滑坡等多处大型古滑坡。受地质灾害的制约,曾三次选址,两次搬迁。经过三期地质灾害及库岸防治工程,区内大部分地质灾害体的危险性已得到控制。但是,随着三峡水库的蓄水至175m,巴东新城区依然存在着一些困扰当地人民生命财产安全和国民经济可持续发展的重要环境地质和工程地质问题有待解决,如:“扇形斜坡是否由于深层滑动形成?斜坡内广泛发育的软弱带是否能构成类似瓦依昂型的滑坡?”。基于以上问题的提出,论文以巴东新城区白土坡和西壤坡两段库岸深300余米的监测剖面的地质勘探资料为基础,结合前人的研究成果,系统地分析了巴东新城区库岸斜坡的岩体结构特征。揭示了库岸斜坡的形成和改造过程以及期间所处的内、外动力地质环境;通过对深部岩体结构的系统研究,构建库岸斜坡的空间岩体结构模型,为预测蓄水后的库岸斜坡深层稳定性提供了可靠的依据;从斜坡岩体结构的组成角度解释已有复杂滑坡的成因机制,分析具不同结构类型滑坡的主要影响因素,为评价类似结构斜坡的稳定性提供了经验参考。通过论文的研究工作,阐明了巴东新城区库岸斜坡的演化过程和稳定性,对分析、防治和减轻地质灾害、保证三峡水库安全蓄水运行具有重要的现实意义和理论意义。论文取得了以下阶段性、创新性研究成果。（1）以谷德振对岩体结构面的5级分类方案为基础,系统总结并丰富了岩体结构面的获取和描述方法。提出了将现场实测、数字摄影和钻孔岩芯解译相结合的Ⅲ、Ⅳ结构面获取方法。该方法通过现场布置标尺校正数码相机的畸变系数;根据现场实测数据的离散值,利用结构面视倾角产状中心距解译产状信息;应用钻孔岩芯破碎程度表征深部岩体结构的完整性。采用超声波技术测试岩体的Ⅴ级微结构面,建立了岩块密度、饱水密度增加率、抗压强度和压实系数与纵波波速的非线性关系。（2）对具有统计意义的Ⅳ级结构面,采用聚类分析方法消除结构面产状分组中的主观性;测窗法获取实际迹长均值时,与测窗边界相交结构面的中心有部分位于测窗外,通过经验对迹线分布数量折减提高了真实迹长均值的精度。通过蒙特卡罗方法对结构面进行了三维网络模拟,并获得了空间岩体ROD等值线分布图。（3）汇总巴东新城区深部钻孔资料,结合野外调查,绘制了巴东新城区巴东组第三段（T₂b³）底板高程图;界定了城区内具有争议的几处主要断层的性质如下,大坪—白土坡前缘两条正断层切穿了T₂b³底板,赵树岭两侧断层为逆冲断层,毛狗梁子断层束在T₂b²地层内无大的垂向升降或平错,属于浅层断层。（4）巴东新城区库岸斜坡在沉积成岩时处于滨海相的复杂环境,T₂b³沉积过程经历了蒸发台地（潮上带）、局限台地（潮间带）、开阔台地（陆棚泻湖）、台地边缘浅滩、开阔台地（陆棚泻湖）、局限台地（潮间带）、开阔台地（陆棚泻湖）、台地边缘浅滩多次反复的海浸海退;软弱夹层形成于沉积环境相对动荡时期,主要分布在开阔台地（陆棚泻湖）和局限台地（潮间带）两种沉积相。巴东新城区经历了复杂的构造应力历史,城区不同部位构造应力作用强度和集中性不尽相同,应力集中带位于西壤坡前缘长江河谷、赵树岭、白土坡及黄土坡前缘地区。区内节理、劈理和层间滑动带普遍发育,为斜坡复杂变形提供了构造条件。受表生外动力改造影响,巴东新城区库岸在长江下切过程,形成的拉伸应力区主要集中在临近河床的陡坡段、坡体后部断层带或软硬岩接触带,及地形变化部位。地下水在岩体结构表生改造中充当了重要角色,由于泥灰质岩石兼具了灰岩溶蚀性和泥岩风化性两方面特征,地下水的改造作用首先沿结构面发生,其改造结果受初始结构面性质及规模的控制。通过岩体结构的演化过程反演了巴东新城区库岸斜坡的地质演化过程,解释了T₂b²和T₂b³界面是否存在明显滑动面的问题,认为二者接触段属于连续过渡,不具备滑动条件,滑动主要沿着接触面上、下一定范围内的软弱岩层接触面发生。（5）采用深部岩体结构完整性的分类方法,对白土坡和西壤坡两段库岸深部岩体的完整程度进行系统划分,分为优、良、中、差和极差五级,受两段库岸岩性和构造特征控制,白土坡岩体完整程度相对西壤坡略差,白土坡前缘断层上盘岩体相对下盘岩体差。（6）通过岩石试验能耗分析岩块的强度,采用峰值外荷做功和岩块破裂耗能表征岩块的软硬程度,采用峰前峰后破裂能比和破裂能耗散率表示岩块的脆、粘性程度。试验结果表明,岩块的软硬程度在垂向上分布不均,与岩石的沉积环境、矿物成分密切相关,岩石的矿物成分灰质高者的强度相对于粘土质高者要大。依据岩体完整程度和软弱带分布,对白土坡和西壤坡两段库岸进行强度分带,采用岩体地质强度参数GSI估算岩体强度参数,并划分了4个强度等级。（7）从构造、结构、分布、成因和强度几个方面,对巴东新城区库岸深部软弱带开展了系统研究。T₂b³岩层内发育13层贯通的软弱带,按照软弱带的物质、结构特征可分为富粘土质软弱夹层、碎裂岩软弱带、溶蚀改造软弱带及软岩软弱带四类。软弱带的成因主要受原岩沉积和构造作用的控制,破碎带形成后又经历了地下水的表生改造,灰质成分部分被溶蚀,粘土质含量相对提高,河流继续下切重新胶结即形成了现今的软弱带结构。采用电镜扫描（SEM）获得软弱带的微观结构,发现软弱带内普遍发育擦痕、矿物定向排列,反映了软弱带存在深部蠕滑的特征。从地质演化和尺度效应两个角度分析了软弱带的综合抗剪强度,认为软弱带形成后经历了河流下切引起的地下水变动改造,其发展方向可分为两种,其一是溶蚀软化,发生在地下水循环强烈时,其二是重固结强度再生,发生在地下水滞留或无地下水环境;含碎石软弱带强度类似含微裂隙岩体强度,具有明显的尺度效应,结合试验数据和巴东新城区滑坡滑带土强度数据,认为软弱带剪切摩擦角取25-30°较合理。（8）根据结构面的性质、密度、产状与斜坡的交切关系,将斜坡岩体结构划分为四大类、十二亚类。三峡库区库首至巴东段库岸斜坡岩体结构和滑坡的统计结果表明,变倾角同向岸坡是滑坡最发育的岩体结构,此类结构发育在构造作用的集中部位,滑面表现为圈椅状或波状起伏。在考虑滑坡侧向边界阻滑效应的基础上,结合直剪试验岩桥贯通理论,以T₂b²和T₂b³作为软硬岩代表,推导了同向坡结构岩层倾向和坡向夹角的上限值的求解过程,认为夹角上限值与岩性软硬程度有关,硬质岩上限值低于软质岩。（9）考虑到库岸斜坡岩体结构的尺度效应,提出了区域、城区、斜坡点三个层面的库岸斜坡岩体稳定性评价系统以巴东新城区作为区域、城区库岸斜坡岩体稳定性评价实例,提出基于岩体结构模糊识别和信息量模型的空间斜坡岩体稳定性评价方法。通过粗糙集获得模糊模式识别的指标权重,并应用模糊理论进行斜坡岩体结构识别;在岩体结构分类的基础上应用信息量模型进行库岸斜坡空间稳定性评价,将评价结果与现有滑坡灾害发育情况对比,验证了方法的合理性。以巴东新城区库岸发育主要的斜坡岩体结构为例,探讨了不同岩体结构斜坡点稳定性的评价方法。首先,对滑面具有两段结构和强度本构关系的顺层同向坡,即顺层主滑段具备应变软化特征、切层抗滑段具备弹脆性特征,采用尖点突变理论探讨了顺层滑坡的发生条件。顺层滑坡的稳定性和两段材料的刚度比及坡形有关,结合试验和经验数据,认为刚度比与滑面的正应力和剪切次数有关。当前缘卸载或后缘加载时,均导致刚度比下降,容易诱发斜坡突变;年内周期性的库水位升降和降雨均相当于在滑面上开展反复剪,导致滑面刚度比发生变化,进而解释了为什么滑坡发生通常经历多次的位移加速过程;其次,对于切层滑坡或楔体滑动,滑动面通常沿结构面贯通形成,提出遍布连通率的计算方法,获得了沿剪切面最小单位面积抗剪强度的概率分布模型;最后,基于白土坡库岸深部岩体结构完整性和强度分带,通过数值分析方法模拟了水库运营后渗流场和应力场的变化,基于FLAC所提供的强度折减法计算了不同工况下库岸斜坡的深层稳定性,认为库岸在未来水库运营中整体处于稳定状态,在强度折减的极限状态滑动面沿深部软弱带发生剪切贯通。论文紧紧围绕巴东新城区库岸斜坡300余米的岩芯开展研究工作,所获取的岩芯资料十分宝贵,不仅揭示了城区内主要易滑岩层T₂b³的地质演化历史和深部结构信息,而且对解释区内主要滑坡的成因具有指导意义。通过对巴东新城区岩体结构的研究,构建了一套系统的岩体结构评价模型和方法,所提出的岩体结构动态演化性和多尺度的评价模型对评价同类型的斜坡岩体结构具有一定的理论意义,所取得的研究成果对指导巴东新城区工程建设,预测水库蓄水后的库岸斜坡稳定性的发展趋势具有重要的现实意义。更多还原

【Abstract】 Rock mass,existing in a certain geological environment,is a special geological body with certain rock component and structure,and in the long geological history it has experienced repeated geological activities,frequent deformations and failures.Rock mass structure cybernetics proposes that rock mass structure not only reflects the tectonic evolution history, also controls its deformation-failure character.Based on the viewpoints mentioned above,the thesis makes a systematic research on rock mass structure of shoreline slope in New Badong Country,three Gorges reservoir.Due to its poor geological condition,there exist plenty of ancient landslides in the new Badong county,i.e.Huangtupo landslide,Zhaoshuling landslide etc.Although almost landslides have been controlled by geological disasters and its engineering treatment for three times,while with water storage level up to 175cm,still some environmental geology and engineering geology problems bothering residents in the New Badong Country needed to be solved,such as " whether fan-shaped slope is formed by deep sliding?" "if Vojoint landslide is formed by the weak and soft zones developed in shoreline slope slide?" Regarding to above-mentioned questions,the thesis analyzes structure of shoreline slope in New Badong Country based on both observation data of monitoring profile（300m deep）and others’ achievement;indicates the formation and evolution process of shoreline slope slide and internal and external geological enviroment during its development;sets up a spatial model of rock mass structure via systemetic research of its deep structure which provide a reliable basis for deep stability forecast of shoreline slope after water storage;explains the formation mechanism of complicated landslides existing in terms of rock mass structures of slopes;studys the main influence factors of different landslides to provide reference for evaluation of similar structural slopes’ stability.To conclude,this thesis illustrates evolution process and stability of the shoreline slope in New Badong County and has theoretial and pratical significance for analysis, reduction and prevention of geological disaster.Phased achievements included are as follows.（1）Based on Gu Dezhen’s classification of 5 grades on rock mass discontinuity,the thesis summarizes and perfects the acquisition and description method of discontinuity;proposes the acquisition approach ofⅢ、Ⅳdiscontinuity,combining field measurement,digital photography and rock core analysis together.The method has three innovations,firstly correcting distortion coefficient of digital camera by field scale.Secondly the strike-dip of discontinuous is interpreted by comparing the discrete degree with field measurement data.Finally the integrity degree of deep rock mass structure is represented by the RQD,quality coefficient and fractal dimension value of rock core.According to the ultrasonic detection data,the fifth degree discontinuity is described by the nonlinear relation of density,density increment from drying to saturation,compressive strength,compaction coefficient and longitudinal wave velocity of rock block.（2）Fuzzy cluster method（FCM）is applied to eliminat subjective uncertainty when dividing discontinuity group.The author improves precision of discontinuity’s mean trace length by empirical adjusting the intersected number of discontinuity and sample window.The contour map of spatial RQD of rock mass is drawn by simulating three-dimensional network of discontinuity.（3）By combining deep borehole with field investigation data,the bottom contour map of third Member of Triassic Badong Formation（T₂b³）is drawn,the character of disputed faults is defined.Two stripes of normal faults cut through the bottom of T₂b³ on the front of slope from Daping to Baitupo.The faults are thrust fault on both sides of Zhaoshuling landslide.The Maogouliangzi faults belong to shallow fault which haven’t long distantness vertical lifting or horizontal offset in the stratum of T₂b².（4）Reservoir shoreline slope in New Badong county was in the complex littoral facies environment in sedimentation time.T₂b³ sedimentation undergoes a repetitious marine transgression and regression process,which includes evaporate platform（supra-tidal belt）, restricted platform（inte-rtidal belt）,open platform（shelf lagoon）,platform edge shoal,open platform（shelf lagoon）,restricted platform（inter-tidal belt）,open platform（shelf lagoon）as well as platform edge shoal;weak intercalation,which is mainly distributed in open platform （shelf lagoon）and restricted platform（inter-tidal belt）,was formed in the period of relatively dynamic sedimentary environment.New Badong county undergoes a complex past of tectonic stress.For different areas,action strength and stress concentration are different.Especially Yangtze River valleys in front of Xirangpo Slope,Zhaoshuling Slope,Baitupo Slope as well as front of Huangtu Slope hold a concentrated tectonic stress.In this region,joint,cleavage and interlayer sliding belts develop widespreadly,which provides tectonic conditions of complex deformation of slope.Affected by super-genic transformation of external dynamic force,tension stress areas in the reservoir shoreline of New Badong county,formed in the process of Yangtze River cutting, focused on steep slope section near riverbed,fault zones in the end of the slope,contact zones of soft and hard rock as well as changing zones of terrain.Underground water plays an important role in the super-genie transformation of rock mass structure for two characteristics,i.e. dissolution of limestone and weathering of mudstone of mud-limestone,transformation action of underground water irstly occurs along structure plane,while its result is controlled by original structure plane property and scale.The geological evolution process of reservoir shoreline slope in New Badong county is reflected by that of rock mass structure,which explains whether obvious sliding plane exists in the interface between T₂b² and T₂b³.Yhe result shows that the interface between T₂b² and T₂b³ is continues transition without no sliding conditions,and the sliding mainly occurs in the interface of soft strata at the certain range of the interface between T₂b² and T₂b³.（5）The classification method of deep rock mass structural integrity is adopted to make the systemetic division of Baitupo Slope and Xirang Slope into five ranks,i.e.excellent,very good, good,poor and very poor.Controlled by reservoir shoreline litho-logy and structure features in these two slopes,the integrity degree of rock mass in Baitupo Slope is poorer than Xirangpo Slope,and the integrity of rock mass of upper block is poorer than footwall rock mass in the front of Baitupo Slope.（6）Rock block strength is analyzed by energy consumption in rock test,using the work of peak external load and the energy dissipation of rock block rupture to characterize soft and hard degree of rock block,use the fracture energy ratio between the Pre- and Post-peak and the dissipation rate of fracture energy to characterize the brittle and viscous degree of rock block. The results show that the soft and hard degree of rock block is uneven distribution in vertical direction,it is closely related to the sedimentary environment and mineral composition of the rock and the strength of the rock whose gray matter is higher in mineral composition is greater than the rock whose clayish fine is higher.According to the integrity degree of the rock and the distribution of weak and soft zone,the author carries on intensity zoning in the reservoir shoreline of Baitupo and Xirangpo,estimates strength parameter of rock mass via geological strength index（GSI）and divides it into four strength grades.（7）In terms of tectonic structure,distribution,genesis,strength etc.,the author carries on system research for reservoir shoreline deep weak and soft zone in New Badong City.13 strips transfixion weak and soft zone which develops in the T₂b³ strata can be divided into weak intercalation being rich in clayish fine,cataclasite weak and soft zone,corrosion transformation weak and soft zone and soft rock weak and soft zone according to the substance in weak and soft zone and structural characteristics.The genesis of weak and soft zone is most controlled by the deposition and tectonism of original rock.After the formation of fracture zone,and then, fracture zone is subjected to the supergene transformation of groundwater,gray matter composition is corroded,so the content of clayish fine is relative increasing,river continues down-cutting and recementing to form present weak and soft zone structure.With electron microscope scanning（SEM）,the author obtains the microstructure of weak and soft zone,and find that weak and soft zone widespread develop scratch and the minerals show directional alignment,all of that reflect the characteristics that weak and soft zone exists deep creep. Analysising the comprehensive shear strength of weak and soft zone from geological evolution and scale effect,the author thinks it experiences groundwater change transformation caused by river down-cutting after the formation of the weak and soft zone.Its development direction can be divided into two species,one hand is corrosion softening,which happens when the groundwater cycle becomes strong,strength recycled after repeat consolidation,which happens in the environment of groundwater retention or no groundwater.The strength of weak and soft zone which contains crushed stone is similar to rock mass strength which contains microfissure, and it has obvious scale effect.According to the test data and the strength data of landslide slip belt soil in Badong new urban,the author thinks it is more reasonable that the angle of shearing resistance in weak and soft zone takes 25-30°.（8）Based on the properties,density of structural plane and its intersected relations with slope,the rock mass structure of slope is divided into four classes,twelve subclasses.The statistical results of rock mass structure and landslides from head of the Three Gorges reservoir to Badong shoreline indicate that the variational inclination co-rotating shoreline slope is a kind of the most developmental rock structure.This kind of structure develops in the concentrated part of tectonism,the slip surface is chair-shape or wavy.Considering the resistance effect of the lateral boundary of slope,combing rock bridge failure theory of the direct shear test,represented with T₂b² and T₂b³,the solving process of upper limit value of angle between strata’s inclination and aspect of co-rotating slope is derived.It holds that the upper value of angle is relative with the degree of soft and hard,the hard rock’s upper value of angle is lower than the soft rock’s.（9）considering the scale effect of rock structure,the evaluation system of rock stability of shore slope is proposed which is three levels including region-urban-single slope.Using new city zone of Badong as the example of regional,urban rock stability evaluation of slope,the spatial rock structure evaluation method based on rock structure fuzzy recognition and information model is proposed.The index weight of fuzzy recognition is obtained from rough set,and the rock structure is recognized by fuzzy theory.Basing on the classification of rock structure,applying information model to evaluate spatial stability of slope,the comparison between evaluation results and present hazard is done,which verifies the rationality of the method.Using the main slope rock structure developed in shoreline of new city zone of Badong,the stability evaluation method of single slope which has different rock structure is discussed.Firstly, the consequent layer co-rotating slope whose slip surface has two kinds of structures and strength constitutive relations,that is main slip segment of consequent layer has the characteristics of strain softening,and resistance segment of incision layer is elastic brittle.Cusp catastrophe theory is used to discuss the occurrence condition of consequent layer slope.The stability of consequent layer slope is relative with stiffness ratio of the two material and slope shape,combing test and experience data,it holds that stiffness ratio is related with normal stress and times of shear of slip surface.When the front unloads or the back edge loads,the stiffness ratio will decrease,it is easy to induce slide.Periodical lifting of water level and rainfall annual is equivalent to repeated shear on slip surface,it leads to the change of stiffness ratio,that’s why the slide is always associated with many times displacement acceleration.Secondly,for incision layer or wedge slide,slip surface is always formed by transfixion of structural plane,proliferates connected rate is proposed,probability distribution model of minimum unit area shear strength is obtained.Finally,based on the deep rock structure and intensity zoning of Baitupo slope, using numerical analysis to simulate the change of seepage and stress field after the operation of reservoir.Based on strength reduction of FLAC,the deep stability under deferent condition are calculated,it holds that the shoreline is overall stabile during the operation of the reservoir, under limit state of strength reduction,the slip surface is shear transfixion along zone of weaknessThis thesis pays its priority on 300-meter core in New Badong county,the research data of rock core is very valuable,not only reveals the geological evolution history and deep structure information of T₂b³,the main easy-sliding stratum,but aslo it is significant to interpret the formation cause of main slides.And meanwhile a set of systematic evaluation models and methods are established via rock structure research in New Badong county.Dynamic evolution of rock structure and multi-scale evaluation model proposed in this thesis has theoretical significance for similar slope evaluation.The research results have important practical significance for engineering construction in New Badong county and stability prediction of shoreline slope after water storage.更多还原