Structural mechanism and construction method of mud and water inrush in Xiangyun tunnel of Guangtong-Dali railway

Mud and water inrush in tunnel is a common problem in the construction process. Nowadays, the research and classification on this are mostly focused on karst situations. According to the characteristics of the surrounding rock and damage forms of the tunnel in the studied area, the author analyzed the geological and structural characteristics of mud and water inrush in tunnel and obtained their construction type. Meanwhile, the advanced water detection under the complex geological conditions was studied by using induced polarization method, transient electromagnetic method and three-dimensional seismic method, it can be concluded that the water-rich fracture zone exists within the detection range with a risk of large mud and water inrush disaster. The concrete construction treatment measures are put forward:①cement-water glass binary slurry is selected as the material for ground and hole grouting, its advantage is that the gel time can be controlled, and it has certain grout ability in the strata with large permeability coeffcient, which is conducive to excavate construction immediately after grouting.②applying the mature retrograde grouting construction can reduce grouting time and improve the excavation efficiency.

A state‑of‑the‑art review on rock seepage mechanism of water inrush disaster in coal mines

Water inrush is one of the most dangerous disasters in coal mining.Due to the large-scale mining and complicated hydrogeological conditions,thousands of deaths and huge economic losses have been caused by water inrush disasters in China.There are two main factors determining the occurrence of water inrush:water source and water-conducting pathway.Research on the formation mechanism of the water-conducting pathway is the main direction to prevent and control the water inrush,and the seepage mechanism of rock mass during the formation of the water-conducting pathway is the key for the research on the water inrush mechanism.This paper provides a state-of-the-art review of seepage mechanisms during water inrush from three aspects,i.e.,mechanisms of stress-seepage coupling,fow regime transformation and rock erosion.Through numerical methods and experimental analysis,the evolution law of stress and seepage felds in the process of water inrush is fully studied;the fuid movement characteristics under diferent fow regimes are clearly summarized;the law of particle initiation and migration in the process of water inrush is explored,and the efect of rock erosion on hydraulic and mechanical properties of the rock media is also studied.Finally,some limitations of current research are analyzed,and the suggestions for future research on water inrush are proposed in this review.

Formation mechanisms of water inrush and mud burst in a migmatite tunnel：a case study in China

This paper presents a case study of water inrush and mud burst occurring in a migmatite tunnel to study its formation mechanisms. The geological investigation and mineralogical analysis showed that water inrush and mud burst in the migmatite was closely related to the component of the host rock. High content of soluble minerals,e.g.,calcite and dolomite,would make the migmatite rock prone to be fragmentized,isintegrated and eventually form different sorts of connected or semi-connected veins. The field exploration revealed most cavities in the magmatite tunnel were eroded by groundwater and formed large interconnected networks. The two faults and the dike in the magmatite tunnel became the preferred paths and provided great convenience for plenty of precipitation and mud slurry. Due to high water pressure and blast disturbance,the cavities can soon connect each other as well as all sorts of veins,forming a complex ground channel for water inrush and mud burst. To estimate the potential occurrenceof water inrush and mud burst,the water bursting coefficient was employed. The results showed the water bursting coefficient of the magmatite tunnel was much bigger than the threshold values and it can be used to explain the accident of water inrush and mud burst occurring in the magmatite tunnel.

Study on Mechanism of Water Inrush of Karst Tunnels

Water inrush,which is one of the challenging issues and hot topics in the tunneling industry,is very easy to occur during the construction of karst tunnels.The mechanism of water inrush of karst tunnels is discussed and analyzed in the paper:the water inrush of karst tunnels is generally divided into three steps,i.e.,the forming of the hazard source,the forming of the water inrush passage and the failure of the anti-inrush rock mass.The failure of the anti-inrush rock mass of karst tunnels are classified into 5 types,i.e.,the integral tensile-shear failure,the hydraulic fracturing,the infiltration induced sliding of the filling medium,the loss of key blocks and the comprehensive water inrush mode.The failure mechanism is studied on basis of typical cases and by means of numerical simulation or theoretical analysis.Conclusion is drawn that most of the water inrushes in actual tunneling are comprehensive water inrushes,which are the comprehensive results of the interrelation and interaction of various water inrush types,and that different types of water inrushes have related continuity and progressive evolution relationships under certain conditions.

Mechanical model of water inrush from coal seam floor based on triaxial seepage experiments

In order to study the mechanism of confined water inrush from coal seam floor,the main influences on permeability in the process of triaxial seepage experiments were analyzed with methods such as laboratory experiments,theoretical analysis and mechanical model calculation.The crack extension rule and the ultimate destruction form of the rock specimens were obtained.The mechanism of water inrush was explained reasonably from mechanical point of view.The practical criterion of water inrush was put forward.The results show that the rock permeability "mutation" phenomenon reflects the differences of stress state and cracks extension rate when the rock internal crack begins to extend in large-scale.The rock ultimate destruction form is related to the rock lithology and the angle between crack and principal stress.The necessary condition of floor water inrush is that the mining pressure leads to the extension and transfixion of the crack.The sufficient condition of floor water inrush is that the confined water’s expansionary stress in normal direction and shear stress in tangential direction must be larger than the internal stress in the crack.With the two conditions satisfied at the same time,the floor water inrush accident will occur.

基于流-固-损伤全耦合模型的裂隙型岩溶突涌水数值模拟

岩溶地区隧道建设频遇突涌水灾害,裂隙型突涌水勘察与预测难度极大、致灾风险高。为揭示裂隙型岩溶突涌水机理与明确前兆信息,基于流-固-损伤耦合模型对裂隙型岩溶突涌水致灾机理与临界条件展开研究。通过公式推演与多场耦合数值分析得到以下结论:建立了完整的流-固-损伤耦合裂隙型岩溶突涌水致灾机理数学模型,并论证其可行性与合理性;分析了不同溶腔水压工况下,隧道拱顶围岩位移演化规律。结果表明,裂隙型岩溶突涌水与富水溶腔水压高度相关;分析了临界突水条件下围岩特性,提出了缓慢增长段-快速增长段-位移失控段的三阶段裂隙型岩溶突涌水围岩位移演化规律。

Analysis of the Mechanism of Water Inrush Geohazards in Deep-Buried Tunnels under the Complex Geological Environment of Karst Cave-Fractured Zone

To study the mechanism and evolution process of water inrush geohazards under the complex geological environment of the karst cave-fractured zone,a large-scale physical threedimensional(3 D)model test was first performed.Then the conceptual model for the evolution process of water inrush geohazards and the simplified theoretical model for the critical hydraulic pressure were both established based on the main characteristics of the water inrush geohazard in the engineering background and that in the model test.A new method was developed for modeling the geological environment of the karst cave-structural plane,and two formulae describing the critical water pressure of water inrush geohazards under two failure models of tensile-shear fracture failure and compressionshear fracture failure were also deduced based on fracture mechanics.The results showed that:(1)the evolution process of the water inrush geohazard can be divided into four stages,which include the initial balance,the propagation of original cracks,the formation of the dominant water inrush channel,and the instability of the waterproof rock mass;(2)the suddenness of water inrush geohazards becomes stronger with the increase of the hydraulic pressure;(3)the calculated critical hydraulic pressure of water inrush geohazards is similar to the measured critical hydraulic pressure in the model test,which validated the accuracies of the theoretical model,and the failure model of water inrush geohazards in this research is compression-shear fracture failure.

基于应力-渗流-损伤耦合效应的断层活化突水机制研究

基于大量煤矿断层突水案例的系统调查分析和归类统计,研究充填型断层滞后突水的灾变演化机制,分析采动条件下断层形态产状、充填性、导水性的变化及其对断层活化突水通道形成过程的影响。以承压水下开采的充填断层为例,分析充填介质距含水层远近的弹性区和应变软化区的力学特性和渗流特征,将水致弱函数引入充填介质的剪应力和变形的本构关系中,建立断层充填结构滑移突水的燕尾突变模型,由系统势能函数的分叉集导出突水灾变演化路径的主控因素;对于承压水上开采的充填型断层,分析充填介质失效过程的渗流损伤特征。考虑充填介质的压剪和拉剪双重破坏准则,引入适合描述充填介质损伤前后阶段的应力-渗流-损伤耦合方程,采用有限元数值仿真真实再现采动应力扰动和高压承压水双重作用下底板采动裂隙演化、断层介质活化直至突水通道形成的灾变演化过程。通过对不同断距和倾角的断层突水过程的仿真分析,揭示突水通道形成过程中岩体应力场、渗流场以及损伤场的耦合效应,实现对不同突水通道形成轨迹的路径记录和准确定位,归纳出断层活化突水的4种典型破裂通道类型。研究结论对我国煤矿突水机制与灾害防治的认识具有一定的指导和借鉴意义。

基于“情景-应对”的矿井水灾事故应急决策机制

为解决矿井水灾事故应急快速反应、高效决策的现场需求,针对矿井水灾事故的不确定性、复杂性和紧迫性等特点,运用多案例分析法,解析了11起典型矿井水灾事故,提出了判别"情景"和事故"情景"两个关键概念,定义了集合{突水水源,突水通道,采掘方式,出水量,淹没范围,生存空间}为矿井水灾事故的情景,并运用AHP分析法计算了6个情景要素各自的权重。确立了"情景–应对"应用在矿井水灾应急决策领域的实现途径,详细阐述了构建情景库、案例库、对策库的方法以及"情景–应对"型矿井水灾应急决策方案的生成过程,并提出了以"黄金72小时""8天8夜"为时间节点的多阶段矿井水灾事故应急决策机制,案例推演应用表明,该应急决策机制不仅规范了事故应急流程,而且实现了精准、快速、高效的目标。

特厚煤层分层综放开采断层-离层耦合溃水机理

为了研究在复杂条件下断层-离层耦合溃水的机理及制定相应的防治水措施,在分析了老虎台井田地质、水文地质和开采条件的基础上,结合水害事故,采用数值模拟和相似材料模拟两种方法,对特厚煤层分层综放开采工作面"两带"发育高度、断层和离层空间形成特征进行了定量化研究,工作面回采后的冒采比和裂采比分别为4. 98～5. 42和7. 10～7. 30;断层空间形态和大小主要受到断层落差和与工作面距离影响;离层空间主要形成于不同岩性接触面附近。基于工作面顶板断层和离层空间形成、充水和溃水过程分析,揭示了断层-离层耦合溃水机理:上分层工作面回采导致覆岩中产生断层和离层空间,在接受含水层的持续补给后形成断层和离层水体,下分层工作面回采产生的垮落带波及至水体后发生溃水事故,与以往断层水害和离层水害相比,具有以下特点:断层和离层同时作为水害事故的充水水源和导水通道;垮落带是导致水害发生的主要因素;水害的孕育和发生分别在不同的工作面。针对水害特点提出了相应的防治水方案,首先对研究区进行水害威胁程度分区,受水害威胁轻及较轻区域的煤炭资源可以正常回采,受水害威胁较重及重区域的煤炭资源必须采取以下措施方可回采:注浆充填已形成的断层和离层空间,疏放已形成的断层和离层水体,减少工作面回采对覆岩中断层和离层水体的扰动。根据典型工作面的安全回采,初步验证了溃水机理的正确性和防治水方案的可靠性,下一步将根据井上、下工程验证,补充和完善防治水措施。

水-力耦合和隔离状态下孔道砂岩力学特性的对比

岩石的水力学特性与矿山突水灾害密切相关,为揭示不同的水岩力学相互作用,对比研究在水-力耦合与隔离2种不同力学状态下孔道砂岩力学特性的差异性。采用MTS815岩石力学试验系统,进行不同围压和孔压下孔道砂岩的常规三轴压缩试验。整个试验围压σ3分成10,20,30 MPa共3个系列,每个系列围压试验中,孔压P设为4个级别,分别是围压σ3的20%,40%,60%和80%。对水-力耦合下的岩石试件用热缩管进行包裹,对水-力隔离下的岩石试件加装隔水装置,在三轴静水压力状态(σ1=σ2=σ3)下采用0.005 mm/s的加载率对试件进行轴向加载,直到试件破坏。结果表明:水-力耦合状态下,孔道砂岩的峰值偏应力强度、扩容起始偏应力、残余偏应力强度和变形模量与围压呈正相关关系,与孔压呈负相关关系,而泊松比的关系则正好相反,试件呈现出明显的单一剪切面破裂,破裂角分布在53°~69°变化;水-力隔离状态下孔道砂岩峰值偏应力强度、扩容起始偏应力和残余偏应力强度均与围压和孔压在总体上呈正相关趋势,水-力隔离状态下试件破裂角变化不明显;在一定的围压与孔压下,处于水-力耦合下试件峰值偏应力强度和变形模量在总体上低于水-力隔离状态下的相应量值,而泊松比的关系则正好相反,随孔压的增加,2种力学状态下的岩石力学特性差异越大。水-力隔离状态内孔壁施加适量应力可以明显提高试件的三轴承载力。

采动应力-承压水耦合下煤层底板突水机理研究

煤矿开采过程中,煤层底板受采动应力及承压水影响会发生变形失稳破坏。为揭示开采扰动承压水耦合下煤层底板突水机理,基于离散元及有限元建立了开采扰动承压水耦合力学模型,分析了开采扰动承压水耦合作用下煤层底板变形及应力分布特征,通过工程应用验证了力学模型的准确性。结果表明:煤层底板突水是开采扰动承压水耦合相互作用问题,应采用应力渗流耦合手段进行解决;水的流量对渗透系数影响不大,随着流量的增加渗透系数略有增加,此外,渗透系数与轴向应力之间为非线性关系,因此可以采用指数函数来描述其非线性关系。

Analysis on the Characteristics and Laws of Tunnel Hydraulic Inrush in Karst Area

As highways are extended to deep mountains,high altitudes,and special geological conditions,tunnel construction becomes more and more challenging,especially the construction of tunnels in karst areas.Due to the particularity of the regional geological structure,karst is well developed in the southwest of our country,especially at areas where the problem of tunnel water inrush in karst areas is more prominent.To further ensure the safe construction and operation of tunnels,the characteristics of tunnels in karst areas is analyzed in this article.

木瓜矿10-103工作面陷落柱区域突水机理及危险性评价

为评价10-103工作面X11陷落柱突水危险性,通过分析岩溶陷落柱突水机理,结合陷落柱的赋存特征确定采用模糊评判法进行突水危险性分析。根据陷落柱特征选取五项主要影响因素,采用层次分析法确定各项因素的权重值,通过模糊评价步骤得出X11陷落柱具有极大的突水危险性,工作面回采推进至X11陷落柱区域前需采取有效的疏水降水措施。

隧道突涌水灾害缩尺物理模型试验研究综述

随着我国经济的快速发展,隧道工程建设越来越多地面临着大埋深、高地应力、高地温、高渗透压力等复杂地质环境,运用物理模型试验开展复杂环境下隧道突涌水灾变机理与安全防控研究已成为岩石力学的热点问题。结合近年来国内外针对隧道突涌水灾变缩尺物理模型试验开展的研究工作,重点对该类物理模型的流固耦合相似理论、相似材料研制、渗透压加载方法等内容进行了系统梳理,并对下一步的可能发展方向进行展望。参考部分文献和突水典型案例后,总结了流固耦合相似准则和高地应力下的相似准则、相似材料选用方案及材料配比、试验中的水压加载方案,认为未来关注的重点包括考虑温度场的物理模型试验相似准则的研究和涌水涌泥与突水突泥间渐变过程的研究2个方面。

煤矿“Y”型断层分支底板断裂力学判据及模拟研究

【目的】断层分支作为主断层的一部分普遍存在,不易引起人们重视,但断层分支是引起突水的主要因素之一。【方法】以安徽刘庄煤矿为工程地质背景,在考虑Mohr-Coulomb准则岩体压剪断裂判据基础上,建立断层分支渗流与应力双重影响下的断裂力学灾变模型,分析得出断层分支发生劈裂破坏时的临界水压及断层分支到底板破碎区最小安全距离,研究断层倾角、最小主应力、主断层长度和渗透水压对临界水压及最小安全距离的影响规律和主控影响因素,并模拟分析断层分支在采动影响下塑性区及渗流场的演化特征,开展现场压水试验的验证工作。【结果和结论】结果表明:(1)断层分支倾角越大越易发生突水;最小主应力越大,断层分支裂隙越不容易发生扩展;(2)当主断层倾角为60°且断层分支与主断层夹角为60°时,模拟分析结果显示在工作面推进至断层分支正上方位置时,断层导升通道整体活化贯通;当工作面推过断层分支正上方10 m后,断层分支尖端裂隙与工作面底板破坏带贯通并引起底板突水;(3)通过现场压水试验验证了理论计算的正确性,证实断层分支会造成底板裂隙提前与断层相互贯通,引起工作面出水。研究结果可为煤矿采场底板含此类断层分支时的防水煤柱留设提供一定参考。

岩溶地层地铁车站深基坑渗漏灾害成因分析

[目的]富水岩溶深基坑施工开挖常发生基坑侧壁或底部突涌灾害问题,应针对富水溶洞地层深基坑开挖时的渗流稳定性进行深入研究。[方法]依托佛山地铁3号线中山公园站深基坑开挖工程,对深基坑渗流特性及坑底涌水机理进行深入研究,建立了基坑-土体-溶洞三维数值模型,采用等效渗透系数法对岩溶-地层渗流场进行耦合模拟。[结果及结论]通过仿真模拟分析,获得了不均匀地层中岩溶区富水程度对基坑渗流场及涌水量的影响规律,阐明了基坑底部土体竖向平均水力坡降演变特性,揭示了该地岩溶区基坑底部突涌水机理,研究结果可为富水岩溶地区深基坑工程的设计与施工提供参考。

我国不同类别煤层顶板水害致灾机理与防控路径

我国是世界上成煤和赋存条件最复杂的国家,煤层顶板水文地质条件的多样性和复杂性,采动覆岩裂隙场与渗流场耦合的相互性和时变性以及煤层顶板突水的独特性和危害性,造成顶板水害是我国尤其是西部煤矿区的主要矿井灾害之一。为了更好地认识顶板水害和推广现有技术和探索新技术防控此类矿井灾害,在全面分析近年来我国煤层顶板水害事故规律与顶板充水含水层的赋存条件、突水模式、动力特征、力学行为等基础上,系统划分了顶板水害的类型、特征、主要类别的致灾机理及梳理了现有顶板水害的防治技术,并展望了未来顶板水害防治领域的发展方向。研究发现:①顶板水害主体架构包括巨厚基岩含水层涌(淋)水、薄基岩弱胶结层水-砂耦合溃涌、离层空间蓄水储能突水、天窗补给型突水、围岩烧变增透致突等5种类别,集中分布于秦岭—淮河沿线以北地区,陕、蒙、宁是顶板水害主要聚集地。②采动诱发巨厚基岩含水层下覆岩原生裂隙互馈-贯通发育“Z”型离层空间,导致采场出现大面积涌(淋)水现象;基于复合关键层破断力学条件,阐明了薄基岩弱胶结层水-砂耦合溃涌致灾的动力源;构建了离层失稳突水临界判别准则,将离层突水划分为静载扰动、“动+静”载复合扰动、复合煤层开采重复扰动3种模式;红土隔水层缺失及红土薄弱区采动劣化损伤是产生天窗越流补给的主要根源;围岩烧变增透,孔隙度增大,接受临近水源补水后形成新的含水结构体,在采动诱发下烧变岩水涌入采场发生水害事故。③梳理了当前煤层顶板水害“探-放-治”三位一体的解危防控技术体系,提出了井上下共轭联动、钻-采(掘)高位协同地质勘探系统,以防治水“三区”划分为导向的地质保障工作,“煤-水-生态”多目标齐抓共管的绿色开采和防治水理念,以及数智化、透明化矿山水文地质灾害信息维护系统等未来发展方向。

基于层间截流封堵技术的矿井滞后突水治理

结合临汾市某矿突水治理实例,在分析构造、底板扰动破坏、隐伏导水通道基础上,进一步研究了残余有效隔水层在底板水压、两侧煤柱以及采空区中部顶板垮落压实综合作用下二次破坏的形式,确定此次突水是在底板扰动破坏和底板隐伏导水构造基础上,残余有效隔水层受底板水压向上牵引应力和煤柱支撑影响发生二次破坏形成导水通道造成的。并据此提出层间截流封堵治理方案,以110 m水平进尺快速揭露导水通道,注浆15500 t,突水量降低94%,水位抬升14.725 m,成功堵水。可为类似矿井水害治理提供有益借鉴。

大变幅加卸载下特厚煤层底板断层突水机理模拟研究

特厚煤层采场空间大、扰动范围广,强烈大变幅荷载易导致底板断层破裂加剧并诱发水害。数值模拟是揭示特厚煤层底板断层活化与突水机理的重要方法,准确反映大变幅加卸载下岩体破裂与裂隙水耦合特征是其合理性的关键。构建损伤变量与塑性应变、应力之间的相关关系,得到完整岩块的拉、加压卸载损伤演化方程;以平方拉剪应力与Benzeggagh-Kenane为初始、完全断裂准则,建立塑性位移与强度劣化关系,建立加卸载韧性断裂本构关系;基于实验数据建立贯通裂隙加卸载剪切本构关系。以基本方程与状态方程为基础,结合浸没边界方法,形成裂隙岩体水力学模拟理论。由此编制流体动力学-有限离散元CFD-FDEM耦合程序,模拟研究特厚煤层底板断层活化突水过程。结果表明:CFD-FDEM耦合程序可数值实现特厚煤层底板断层从(准)连续体到离散体转化,以及断层带裂隙水运移过程。底板断层采动破坏包络线呈W形,最深位于断层及其上盘(48.6m),最浅位于断层下盘(23m)。特厚煤层采场底板断层及其上盘受到较大超前集中应力,而后在采空区内大幅卸载,导致该位置出现显著二次破坏,并形成主要导水通道。研究成果为特厚煤层工作面底板断层水害防治提供理论支撑。