影响巫峡横石溪马鞍子危岩体稳定性的因素分析

危岩是三峡库区重要地质灾害之一,影响危岩坡稳定性的因素有很多,但总体可归为起控制作用的内在因素和起诱发作用的外在因素两类。内因主要包括组成岸坡的地貌特征、岩土体性质、地质构造、岩土体结构等;外因包括地震、水的作用、风化、人类工程活动等。本文从岩性、岩体结构特征、水体作用、地震、人类工程活动等因素对巫峡横石溪马鞍子危岩体稳定性进行了分析研究,为今后野外高陡岩质岸坡、危岩的调查或稳定性评价提供参考。     

忠县地面石质文物的风化病害研究

忠县地面石质文物风化病害形式有：裂隙状风化、页片状风化、絮粉状风化、松胀状风化。其中以絮粉状风化对文物破坏最为严重。控制风化的主要因素是：岩性和岩体结构、气候和气象条件、人为的污染。现场简易强度测试数据表明，风化石材的力学强度明显下降。最后提出了三峡水库蓄水前，对石质文物搬迁和保护的建议。参加研究工作的还有王金华、陈超平、唐毅烈、邓修甫、卞大巍、黄明元等人。表１３处文物概况Ｔａｂｌｅ１ＳｕｒｖｅｙｏｆｔｈｅｔｈｒｅｅｓｔｏｎｅｃｕｌｔｕｒａｌｒｅｌｉｃｓｉｎＺｈｏｎｇｘｉａｎＣｏｕｎｔｙ表２石材的化学成分（％）Ｔａｂｌｅ２Ｃｈｅｍｉｃａｌｃｏｍｐｏｓｉｔｉｏｎｓｏｆｒｏｃｋｍａｔｅｒｉａｌｓ注：丁房阙石样已非新鲜岩石。表３石材岩块的主要物理力学性质指标Ｔａｂｌｅ３Ｍａｉｎｐｈｙｓｉｃａｌ－ｍｅｃｈａｎｉｃａｌｐａｒａｍｅｔｅｒｓｏｆｒｏｃｋｍａｔｅｒｉａｌｓ注：灰绿色砂岩试验成果取自三峡工程库区环境地质研究有关资料。２石质文物的风化病害分析受自然地质环境及人文环境的制约，３处石质文物的主要环境病害是风化病害。２．１风化病害形式［１］（１）裂隙状风化。这是一种典型的物理风化形式，见于无铭阙和临江岩摩崖造像。无     

Engineering geological characterisation of the rock masses at Tannur Dam site,South Jordan

This paper highlights the geomechanical characterisation of the rock masses exposed at the dam abutments and reservoir area at the Tannur Dam site, South Jordan. The right abutment rock masses are characterised by closely to widely spaced joints. The rock-mass qualities were assigned using the rock-mass rating (RMR) and Q-tunnelling index. Both systems assigned a poor quality for foundation rocks because of the presence of weak rocks. The rock masses constituting the dam abutments exhibit fair quality. The results of packer tests indicate that the hydraulic conductivity of the rock masses of Fuheis-Hummar-Shueib (FHS) and Wadi es Sir (A7) formations range from 10 to 150 Lugeon units (LU). The FHS was characterised by lower LU values compared with A7; this reflects the fracturing characteristics of A7. However, the A7 should be grouted especially the right abutment. However, the FHS needs less grouting because the spacing between joints seems to be tight. The estimated shear strength envelopes relevant to the rock masses of both abutments as well as the foundation rocks were quite similar and, therefore, present similar shear strength characteristics. The shear strength for jointed rock masses showed curvilinear failure planes with average cohesion values of 0.67 and 0.64 MPa and friction angles of 36.5 and 35.5° for dam abutments and the foundation area, respectively.     

四川名山白马沟危岩体稳定性评价与落石轨迹分析

危岩体是指由结构面切割形成的在一定诱发因素下失稳破坏的岩体,其作为常见的自然地质灾害之一,严重影响山区人类生命财产安全。对危岩体的勘查、稳定性评价、风险评价是地质灾害预防的研究难题。受人类工程活动影响,名山县新店镇白马沟内存在多处危岩体。通过对国内外研究文献的查阅分析并结合白马沟危岩体的分布特征、发育特征、崩塌落石运动特性进行分析与研究,初步总结出了白垩系上统灌口组(K2g)危岩体的形成、分布规律及成灾机理,并对该区4个危岩体利用Rockfall进行数值模拟计算,计算其运动速度及运动轨迹,计算岩石弹跳高度及距离等。为此类工程地质条件下的的危岩体稳定性评价及运动轨迹的分析提供参考,同时对于崩塌危岩体灾害预防与减灾技术研究有积极意义。     

四川省汶川县城区某斜坡危岩体破坏模式及治理

危岩体是西南地区威胁交通和居民区安全的重要隐患。特别是“5．12”地震造成了原危岩体的崩塌,同时又形成了大量新的危岩体。汶川县城区某斜坡危岩体可归纳为三种破坏模式：拉裂-滑移式、整体剪切错落式和弯折-拉裂-倾倒式。危岩体失稳后,落石将会以弹跳、滚动和滑动方式沿坡体下落。运用能量守恒定律和运动学规律来确定落石的动能、落距和弹跳高度,采取GPS2型主动防护网、RX-075型被动防护网及落石槽相结合的措施,确保213国道和居民区的安全。     

三峡水库碳酸盐岩区岩溶作用与斜坡破坏

三峡水库峡谷区矗立着大量岩溶不稳定库岸,危及长江黄金水道安全。采用野外勘查和力学分析,对三峡库区碳酸盐岩区岩溶作用与斜坡破坏关系进行深入研究。野外勘查发现,三峡库区碳酸盐岩库岸存在许多与溶洞、溶隙、溶蚀带、溶槽、溶沟等表层岩溶作用有关的斜坡不稳定现象。巫峡段库岸内共发育岩溶地质灾害及隐患点186处,其中滑坡隐患点37处,大型以上危岩体6个。岩体力学分析表明:强降雨、蓄水和岩体劣化会因为有效应力减少、强度下降而造成破裂的节理/裂隙逐渐扩大。同时,水位变动带岩体劣化的裂缝扩展速率比三峡的平均溶蚀率高出约1 300倍,极大地加快了已经进入屈服状态的不稳定岩体的演化进程。溶蚀作用是岩溶岸坡中最基本的作用,库水长期波动加快了岩溶岸坡演化。本次研究将为三峡库区峡谷段不稳定库岸识别和防灾减灾提供技术支撑。      

太白岩体南缘铜(钼)矿化地质特征及找矿标志

在太白岩体南缘发现了铜(钼)矿,圈出铜矿体2个,铜矿化体1个,钼矿化体5个。铜矿体长度245~445 m,平均厚度2.03~2.81 m,平均Cu品位1.57%~1.67%;钼矿化体长度50 m,厚度2.03~2.81 m,Mo品位0.01%~0.54%。铜钼矿化受岩体岩石、构造及蚀变带的三重控制。总结出了岩体、构造、围岩蚀变、氧化物及硫化物露头是寻找铜钼矿的重要标志。对矿区矿石中辉钼矿采用Re-Os法同位素年龄测试,获得模式年龄119.3~123.7 Ma数据,说明本区铜钼矿化形成于燕山晚期。依据矿体与含矿岩体的关系、赋存状态、矿物组分及矿石的结构构造等因素,结合区域上铜钼矿化形成规律,初步认为该矿成因类型可能为与区域性花岗斑岩活动有关的热液型。这一结论对在本区寻找与花岗斑岩活动有关的热液型铜钼矿有着重要的现实意义。     

基于倾斜摄影的高位危岩特征获取和稳定性评价

观音山危岩带对拟建恩广高速万开段庙垭隧道、苎溪河特大桥和临近居民构成安全威胁,急需调查治理,但因危岩地处高位,传统调查、评价手段难以实施。通过地质调查、钻孔取样和室内试验获取基础地质信息;利用倾斜摄影对危岩进行识别、几何特征获取和边界条件分析;以赤平投影法和刚体极限平衡法分别进行危岩带、危岩体的稳定性分析;对不稳定危岩单体利用Rocfall软件进行运动学模拟。结果表明:陡崖发育6处主要危岩单体,体积400～5000 m3不等;岩体受2组节理面切割和结构面组合控制,整体稳定性较差,易发生坠落式和倾倒式破坏;其中W3、W6危岩体在暴雨工况下处于不稳定状态,对拟建工程形成滚动冲击,动能为5～12 kJ不等。研究结果可以为观音山危岩治理措施的选型、规模提供设计参数,为高位危岩的调查防治提供参考,对利用航测手段提高传统地质调查效率和精度做出了新思考。     

吉林省红旗岭矿区7号岩体群地质特征及对地质找矿的指导意义

红旗岭矿区的南东部存在7、32、33号三个岩体,一般统称为7号岩体群。7号岩体是矿区发现含铜、镍矿最大的岩体,32与33号岩体分布在7号岩体的北西部。通过对这三个岩体的地质特征进行分析,利用3Dmine软件建模技术,对三个岩体、岩相、矿体建立三维模型。对模型进行观察、分析,结合成岩成矿地质理论,发现三个岩体是由来自7号岩体的南东部深部岩浆源生成的,岩浆由7号岩体的南东部深部向北西方向侵入,地质历史上三个岩体是一个大岩体,只是经过长期的风化剥蚀和地质构造改造形成目前的3个岩体,显示7号岩体的南东部深部具有找矿潜力。     

震裂山体崩塌形成特征及运动学三维模拟——以汶川县三官庙村崩塌为例

三官庙村震裂山体位于汶川强震区,又于2018年7月20日和2019年8月22日发生了两次震后崩塌灾害,严重威胁坡脚居民生命财产安全.通过对震裂山体危岩现场地质调查、无人机航测和室内三维数值模拟,阐述了震裂山体-崩塌发生的成因机理和动力学过程,并对潜在危岩区的危险性进行了分析评价.研究结果认为,此类崩塌形成过程可划分为3...     

Reinforcing a Dangerous Rock Mass Using the Flexible Network Method

Because the main failure type of a dangerous rock mass is collapse, the treatment of such a mass should focus on controlling collapse failure. When treating dangerous rock masses, disturbing the mass （e. g. by blasting） needs to be avoided, as this new damage could cause collapse. So the self-bearing capacity of the mountain mass must be used to treat the dangerous rock mass. This article is based on a practical example of the control of a dangerous rock mass at Banyan Mountain, Huangshi, Hubei Province. On the basis of an analysis of damage mechanism and the stability of the dangerous rock mass, a flexible network reinforcement method was designed to prevent the collapse of the rock mass. The deformations of section Ⅱ w of the dangerous rock mass before and after the flexible network reinforcement were calculated using the two-dimensional finite element method. The results show that the maximum deformation reduced by 55 % after the application of the flexible network reinforcement, from 45.99 to 20.75 ram, which demonstrates that the flexible network method is effective, and can provide some scientific basis for the treatment of dangerous rock masses.     

金沙江干流水电工程区岸坡失稳危险性预测及防治对策

笔者通过调查研究和综合分析金沙江干流水电工程区岸坡地质背景和岩体力学环境条件，定性分析与定量评价相结合，采用与三峡工程库区岸坡失稳危险性评价相类比的方法，针对崩滑体失稳按总体积的1／8和1／11入江方量进行了计算和按美国土木工程学会涌浪图解计算法计算了入水点及在向家坝坝址、溪洛渡坝址和邻近城镇的涌浪高度，并围绕大坝施工安全、库区周边城镇安全，水库运营安全等方面对岸坡失稳的危险性进行了评价预测，提出了岸坡失稳的防治对策。评价结果表明，向家坝库区和溪洛渡库区土质岸坡坍塌及崩滑体入江和涌浪不会影响水库的正常运行及长期效益。     

四川威远县黄荆沟镇垮岩山危岩成因及防治

四川省威远县黄荆沟镇垮岩山危岩，受恶劣的地质环境条件及地表水入渗的影响，发育形成了最宽达120cm，延伸数十米的宽大裂缝，岩石变形破坏迹象明显，严重威胁到岩下的住户及威煤中学师生的生命财产安全。文章对垮岩山危岩发育特征及形成机制进行系统分析和定性评价，得出了危岩体在饱水情况下处于欠稳定状态，在地震情况下处于不稳定状态的结论。针对危岩特征及成因机制分析，采用预应力锚索锚固，辅以清危、排水的综合治理方案，具有技术可行、经济合理的特点。经过1a多时间的考验，经监测证实治理效果明显，为今后类似的危岩治理起到参考作用。     

A numerical study of flexural buckling of foliated rock slopes

The occurrence of foliated rock masses is common in mining environment. Methods employing continuum approximation in describing the deformation of such rock masses possess a clear advantage over methods where each rock layer and each inter‐layer interface (joint) is explicitly modelled. In devising such a continuum model it is imperative that moment (couple) stresses and internal rotations associated with the bending of the rock layers be properly incorporated in the model formulation. Such an approach will lead to a Cosserat‐type theory. In the present model, the behaviour of the intact rock layer is assumed to be linearly elastic and the joints are assumed to be elastic–perfectly plastic. Condition of slip at the interfaces are determined by a Mohr–Coulomb criterion with tension cut off at zero normal stress. The theory is valid for large deformations. The model is incorporated into the finite element program AFENA and validated against an analytical solution of elementary buckling problems of a layered medium under gravity loading. A design chart suitable for assessing the stability of slopes in foliated rock masses against flexural buckling failure has been developed. The design chart is easy to use and provides a quick estimate of critical loading factors for slopes in foliated rock masses. It is shown that the model based on Euler's buckling theory as proposed by Cavers (Rock Mechanics and Rock Engineering 1981; 14 :87–104) substantially overestimates the critical heights for a vertical slope and underestimates the same for sub‐vertical slopes. Copyright © 2001 John Wiley & Sons, Ltd.     

链子崖危岩体的稳定性研究—中科院武汉岩土力学所历年工作概述

本文介绍我所历年来对链子崖危岩体开展的裂缝相对位移监测、力学试验和稳定性评价等研究情况。对链子崖危岩体裂缝相对位移的长期监测提出了测试原理和方法,制定了实施方案,分析了观测结果,给出了相应的结论。简述了危岩区各层岩土介质力学试验的原理、方法和获得的各项力学指标。根据所获得的资料,对链子崖危岩体和猴子岭斜坡体的稳定性作了评价。     

岩体裂隙受内压力的弹塑性分析

岩体裂隙内常充满具有压力的水或软弱填充物,裂隙受内压荷载扩展破坏是岩土工程关心的问题。将该问题等效为裂隙面受一对I型拉力作用的弹塑性断裂力学问题,采用裂隙线附近分析方法,从平衡方程和岩桥材料的破坏准则出发求解裂隙线附近的塑性应力场,将该应力场与弹性应力场在其弹塑性边界上进行匹配,得出裂隙内的压力大小与裂隙扩展长度之间的关系,以及岩桥断裂时的最大承载力。     

链子崖T_（11）—T_（12）缝段危岩体开裂变形机制

文章全面描述了链子崖Ｔ（１１）—Ｔ（１２）缝段危岩体的开裂形变特征，探讨了危岩体形成的影响因素，如重力、煤层采空区、降雨、水库蓄水、勘探掘进和地震等，指出其破坏机理是重力主导下的不对称的压力拱与悬臂梁（板）弯矩的联合作用。危岩体可以分成具有不同稳定程度的若干块体，治理工程也应针对它们的不同特点而设计。     

Influence of tectonic structures on the Hope Slide, British Columbia, Canada

The Hope Slide, which occurred on January 9, 1965, involved an estimated 47-Mm³ of meta-volcanics and intrusive rocks. Previous workers reported the presence of tectonic structures (faults and shear zones) along the failure surface at the Hope Slide. These tectonic features were investigated in detail to assess their effects on rock-mass quality and the related implications for slope stability. This paper integrates basic field and laboratory concepts from structural and engineering geology. Subdividing the failure area into structural domains allowed distinct discontinuity sets to be associated with specific tectonic structures. The Geological Strength Index (GSI) was used to estimate the rock-mass damage related to the tectonic structures. Low GSI values were seen to outline tectonic damage zones. Point-load tests were used to characterise the compressive strength of rocks adjacent to the tectonic structures. Strength anisotropy, tentatively attributed to damage caused by a large shear zone, was observed in greenstone samples. Seepage zones along the failure surface were observed preferentially along shallow discontinuities that dipped downslope and in rock masses of good quality (GSI > 40). An alternative morphology of the slope failure is proposed by distinguishing between the extent of the surficial damage due to the rock-slope failure and the zone of failed material (depletion zone). For the first time, a kinematic mechanism for the Hope Slide is proposed, based on a preliminary 3-dimensional block model. A pre-1965 DEM was produced from estimates of material lost and gained as reported by previous workers. The pre-1965 DEM revealed that the tectonic structures recognised during fieldwork bounded the material that failed in the 1965 event.     

2017年8月28日贵州纳雍县张家湾镇普洒村崩塌特征与成因机理研究

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塔子山危岩治理工程的数值模拟研究

本文以四川省南部县塔子山崩塌危岩体为例，在分析其变形破坏机制的基础上，提出3种治理方案，并通过数值模拟来确定最优化设计方案。