Catastrophe theory-based risk evaluation model for water and mud inrush and its application in karst tunnels

This paper presents a risk evaluation model of water and mud inrush for tunnel excavation in karst areas.The factors affecting the probabilities of water and mud inrush in karst tunnels are investigated to define the dangerousness of this geological disaster.The losses that are caused by water and mud inrush are taken into consideration to account for its harmfulness.Then a risk evaluation model based on the dangerousness-harmfulness evaluation indicator system is constructed,which is more convincing in comparison with the traditional methods.The catastrophe theory is used to evaluate the risk level of water and mud inrush and it has great advantage in handling problems involving discontinuous catastrophe processes.To validate the proposed approach,the Qiyueshan tunnel of Yichang-Wanzhou Railway is taken as an example in which four target segments are evaluated using the risk evaluation model.Finally,the evaluation results are compared with the excavation data,which shows that the risk levels predicted by the proposed approach are in good agreements with that observed in engineering.In conclusion,the catastrophe theory-based risk evaluation model is an efficient and effective approach for water and mud inrush in karst tunnels.

Prevention and treatment technologies of railway tunnel water inrush and mud gushing in China

Water inrush and mud gushing are one of the biggest hazards in tunnel construction. Unfavorable geological sections can be observed in almost all railway tunnels under construction or to be constructed, and vary in extent. Furthermore, due to the different heights of mountains and the lengths of tunnels, the locations of the unfavorable geological sections cannot be fully determined before construction, which increases the risk of water inrush and mud gushing. Based on numerous cases of water inrush and mud gushing in railway tunnels, the paper tries to classify water inrush and mud gushing in railway tunnels in view of the conditions of the surrounding rocks and meteorological factors associated with tunnel excavation. In addition, the causes of water inrush and mud gushing in combination of macroand micromechanisms are summarized, and site-specifc treatment method is put forward. The treatment methods include choosing a method of advance geological forecast according to risk degrees of different sections in the tunnel, determining the items of predictions, and choosing the appropriate methods, i.e. draining-oriented method, blocking-oriented method or draining-and-blocking method. The treatment technologies of railway water inrush and mud gushing are also summarized, including energy relief and pressure relief technology, advance grouting technology, and advance jet grouting technology associated with their key technical features and applicable conditions. The results in terms of treatment methods can provide reference to the prevention and treatment of tunnel water inrush and mud gushing.

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.

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.

Treatment Design and Construction Strategy for Tunnel Mud and Water Inrush Disaster

With the rapid development of the transportation industry in China,the number and scale of tunnel construction are increasing.Tunneling through fault zones and other complex geological environments is becoming more and more common.In the construction of highway tunnels,due to the special geographical environment and complex geological conditions,mud and water inrush often occur in the tunnel.Water inrush disasters pose a major risk to the construction of highway tunnels and affect the normal construction of highway tunnels.This paper combines the engineering background of the tunnel mud and water inrush accidents,carries out evaluation on the accident treatment measures and the treatment efficiency,and summarizes the main concerns in the construction process and the technical guidelines for dealing with the tunnel mud and water inrush.

陕西省煤矿典型水灾隐患特征及治理技术

陕西省煤炭资源丰富,2022年煤炭产量达7.46亿t,是我国主要产煤省份之一。由于全省煤矿区地质及水文地质条件差异明显,煤矿水灾类型多样,随着近年煤炭开采强度的增大,水灾事故时有发生,防治水形势较为严峻。以煤炭赋存条件为基础,系统总结区域水文地质结构特征,界定典型水灾类型及各类水灾影响区域分布,论述典型水灾的形成机理及特征,并提出了相应的防控技术。研究表明:(1)陕西省主要煤炭产区分为陕北、黄陇、渭北三大区,陕北侏罗纪煤田主要有顶板松散沙层水灾隐患、厚层砂岩水灾隐患、溃水溃沙灾害,局部区域分布有烧变岩对煤矿造成水灾隐患;黄陇煤田主要受顶板巨厚砂岩水灾隐患、离层溃水隐患、泥砂溃涌灾害隐患威胁;陕北石炭—二叠纪煤田和渭北煤田,主要受到煤层底板奥陶系灰岩水灾隐患威胁。(2)陕北侏罗系煤田顶板水灾隐患主要为顶板含水层受开采导水裂隙带扰动形成,导水裂隙波及砂岩含水层或松散沙层可形成持续大流量涌水,部分区域充水强度较大,在短时间水量较大超过排水系统能力时造成顶板水灾,在薄基岩区域垮落带直接导通松散沙层时可转变为溃水溃沙灾害,导水裂隙带影响到烧变岩富水区域时可形成瞬时水量大且持续的烧变岩水灾;黄陇煤田顶板巨厚砂岩含水层受采动导水裂隙带波及形成高强度持续涌水并可能形成顶板水灾,当含水层下部隔水层厚度较大时,可能形成离层溃水灾害,当近煤层顶板岩层松软遇水易崩解时可转变为泥砂溃涌灾害;陕北石炭—二叠纪煤田和渭北煤田,煤层开采底板扰动破坏带或断层等构造导通奥陶系灰岩含水层时,会引发极为严重的底板突水灾害,该类灾害具突发性强、瞬时水量大的特征。(3)各区域的顶板水灾隐患治理技术主要包括钻孔疏泄、注浆治理、开采参数控制等,底板水灾隐患治理技术主要包括区域注浆加固及封堵等;烧变岩水灾隐患主要采取帷幕注浆与钻孔探放有机结合的防治技术。

地下隧洞突水突泥演化过程模拟分析方法

在富水、高压、不良地质条件下,如何评估施工过程中的突水突泥破坏风险等级,是地下隧洞施工设计的难题。正确分析地下隧洞开挖应力与渗流耦合互馈作用,是合理模拟地下隧洞施工开挖突水突泥演化过程的关键。首先,根据开挖荷载释放过程中的围岩损伤演化机理,提出了根据不同变形阶段围岩损伤特性计算相应围岩损伤系数的方法,并分析其对渗透系数的影响。然后,根据围岩破坏特性和突水破坏机理,提出了围岩临界突水系数的计算方法,并根据围岩损伤破坏和渗透破坏程度,将突水突泥破坏划分成4个风险等级,为地下隧洞施工开挖突水突泥破坏风险评估提供了依据。最后,根据渗流变化与应力损伤互馈耦合作用原理,提出了变损伤刚度、开挖荷载加权分级以及渗流荷载迭代施加的耦合计算方法,模拟了地下隧洞施工开挖突水突泥演化发展过程。将该方法运用于工程实际,证明了所提理论和分析方法的合理性,为地下隧洞开挖突水突泥演化判别提供了一个可行的分析思路。

王家寨隧道第三系半成岩富水段涌水突泥机制及风险评估

为探究隧道穿越第三系半成岩富水段时引发的涌水突泥、冒顶等地质灾害机制,依托云南临清高速公路王家寨隧道,通过室内力学试验和模糊层次分析法,对第三系半成岩力学特性、作用机制及涌水突泥灾害风险进行分析。研究表明:1)王家寨隧道第三系半成岩遇水软化特性明显,随着含水率增加其黏聚力先增后减,内摩擦角不断减小,含水率为18%时黏聚力与内摩擦角分别为12.53 k Pa和7.35°,围岩逐渐失稳。2)软弱的第三系半成岩、高地下水量及隧道开挖扰动为王家寨隧道第三系半成岩富水段发生涌水突泥灾害的主要影响因素。3)王家寨隧道第三系半成岩段可按工程地质条件、水文地质条件划分为A、B、C、D 4段,各段涌水突泥灾害风险由大到小排序为B段=C段>A段>D段,其中评估的A段涌泥量与实际涌泥量较为吻合。

自重湿陷性黄土场地地裂缝地铁暗挖隧道涌泥灾害处理与风险控制

[目的]黄土饱和湿陷可能出现地下空洞。暗挖隧道穿过自重湿陷性黄土场地地裂缝设防段时,若遇到地下空洞,易引发涌泥灾害,需采取有效的处理措施,以控制施工风险。[方法]以我国某穿越地裂缝的浅埋暗挖法地铁隧道为例,介绍了该工程的概况及地质情况,以及发生涌泥灾害的概要。地质勘探查明地铁右线隧道上方地裂缝破碎带存在黄土空洞,根据该空洞的地层特性及涌泥风险特征,采取了挂网喷射混凝土、小导管注浆固结、型钢及支撑加固、注浆回填空洞等施工措施。在此基础上,进一步阐述了隧道涌泥体清理、隧道二次开挖过程的风险控制措施。[结果及结论]案例工程涌泥灾害的处理措施,以及隧道涌泥体清理、隧道二次开挖过程的风险控制措施是可行、安全的。措施实施后,快速控制了险情,确保了周边建筑物安全。

深埋隧洞穿高压富水断层涌水突泥分析与处置技术

针对隧洞穿越高压富水断层涌水突泥破坏性强、可灌性差的难题,以滇中引水工程香炉山隧洞过大栗树断裂次级断层涌水突泥灾害治理为例,通过分析隧洞涌水突泥洞段的地质特征、灾害过程与成因,提出了超前钻探、超前灌浆、超前泄压、超前支护组合处置对策。针对隧洞下半断面围岩碎粉含量高、阻止浆液扩散导致注浆效果不佳的问题,提出了置换式注浆加固技术,即注浆孔分A孔、B孔,通过A孔注浆,B孔泄压并冲出岩粉的方式进行注浆,以利于岩粉排出和浆液扩散,成功解决了香炉山隧洞DLI3+681.5涌水突泥灾害治理技术难题。研究成果对类似地质条件下隧洞涌水突泥灾害治理提供参考。

复杂地质条件下岩溶台地隧道灾变风险评估:以安平隧道为例

复式向斜岩溶台地地质条件复杂,隧道穿越时,多发生突水涌泥等地质灾害。以安平隧道为例,在隧道线路设计初期,从地质角度出发,分析隧道线路范围内存在的5个主要地质问题及可能发生的地质灾变风险,并逐一对其进行评估和评价;采用宜避不宜扰的地质选线理念,根据评价结果选择路线绕避方案和确定平纵设计指标。研究成果对类似复杂地质条件下的岩溶台地隧道地质选线和路线设计具有一定的借鉴意义。

隧洞突涌松散介质注浆加固技术与效果评价

为解决滇中引水工程中狮子山隧洞施工中遇到的突泥、突水问题,采用帷幕预注浆技术进行地层加固处治。针对2处地质构造和突涌介质堆积体不同的工程特性,提出了岩石碎屑高压喷射灌浆加固技术和泥质介质渗透性注浆加固技术,并对岩石碎屑高压喷射注浆与泥质介质注浆加固机理、帷幕注浆设计方案、施工工艺和技术、注浆效果综合评价方法进行了深入研究论证。应用结果表明,隧洞突涌体纵向加固范围为30m,径向加固范围为轮廓线以外5m,注浆加固形成了稳定的复合承载帷幕体,确保了该隧洞突涌灾害处治科学可靠,实现了突涌洞段安全掘进。

不同位置承压溶洞对隧道施工影响研究

承压溶洞作为典型不良地质条件,在隧道近接其施工时,容易因为地层渗流的增加及塑性区的发展,产生突水突泥灾害,威胁到隧道施工安全。以金岩隧道工程为例,采用数值模拟手段,研究了近接不同位置(拱顶、边墙、拱底)承压溶洞时,地层与隧道结构的位移与渗流特点。结果表明:溶洞位于拱顶、边墙、拱底的地表最大沉降分别为3.10 cm、3.00 cm、2.93 cm。说明当拱顶存在溶洞时,地表变形最为危险,而拱底溶洞对隧道施工产生的地层扰动影响最小;随着向掌子面的靠近,地层渗流速度逐渐提高,且在临近掌子面时流速呈现陡增形态。3种工况中流速极值分别为0.026 cm/s、0.027 cm/s、0.030 cm/s,拱底流速最大,这是因为拱底溶洞埋深最大,溶洞压力水头最大所导致。当承压溶洞临近隧道边墙时,地层塑性区向溶洞贯通,再结合地层渗流分布,可见此工况最容易发生突水突泥灾害。

富水地层破碎围岩浅埋隧道突水涌泥段大变形处置措施

松散围岩隧道施工中发生突水涌泥危险性极大,处理不慎容易发生二次事故,造成较大的人员财产损失。以牛拦岗隧道左线Z2K219+077及右线K219+081的突水涌泥段的大变形事故为背景,深入分析了项目施工过程中的各种危险因素以及事故的产生原因,并以此提出了一种洞内拱顶环向一圈帷幕注浆加固围岩,并用临时止浆墙来稳定掌子面的方法来抑制突水涌泥以及拱顶大变形现象。根据现场的实际监控量测数据,验证了该方法能有效抑制隧道施工过程中的拱顶沉降速率,对于处置突水涌泥段的大变形问题有实际的可行性。

综合超前地质预报技术在格莱村隧道中的应用

随着我国西南地区岩溶隧道建设数量的逐年增加,隧道施工过程中经常遇见坍塌掉块、突水涌泥等病害,给隧道施工造成了较大的困扰。因此,利用地质调查法、地质雷达法、地震波反射法、超前钻探法、综合预报法相结合的综合超前地质预报技术,对格莱村隧道掌子面前方及洞周影响范围内的工程地质特性和水文地质条件进行勘探,以确保岩溶隧道施工安全。结果表明:格莱村隧道综合超前地质预报效果良好,充分发挥了各超前地质预报方法的优势,提高了超前地质预报的精准度,有效预防了坍塌、掉块、突水、突泥等地质灾害的发生,降低了岩溶隧道的施工风险。

隧道竖向垂直发育充填溶腔突泥处治施工技术研究

文章以新建郑万高铁高家坪隧道竖向垂直发育淤泥质充填喀斯特突泥处治实践为依托,采用地表调查、隧顶底超前探测、理论分析与工程应用等手段,研究揭示了隧道喀斯特突泥致灾机制,提出了“因地制宜、分区处理”的总体处治原则,构建了以突泥分阶段加固+清理、隧顶超前大管棚+钢筋混凝土护拱加强支护、隧底钢筋混凝土拱桥跨越为主的综合处治技术体系,成功解决了该隧道突泥处治技术难题。相关研究成果可为类似条件隧道突泥处治提供借鉴和指导。

山岭隧道富水破碎带突泥涌水处治技术研究

某高速公路高海拔山岭隧道穿越活动断层富水破碎带施工过程中,多次发生大面积突泥涌水。为安全有效处治并通过断层破碎带,结合既往施工技术经验,因地制宜,总结出“探、泄、固、挖”的总体思路,实施“帷幕注浆+水平旋喷桩+超前中管棚+微台阶法开挖”的科学注浆开挖方式,取得了较好处治效果。文章研究内容可为类似隧道灾害处治提供经验。

示踪实验在湾潭隧道涌水突泥判别中的应用

以宜来高速湾潭隧道为研究对象,通过现场调查、地下水示踪实验、地下水流量监测,以及采用大气降雨入渗法计算隧道的平均涌水量和丰水期涌水量,同时采用RFPA渗流软件对隧道涌突水的可能性进行判别。现场调查及示踪试验结果显示湾潭隧道岩溶管道为多支,混合型岩溶管道,水文地质条件复杂,丰水期涌水量约为平均隧道涌水量的4.6倍。数值模拟结果表明,隧道涌水突泥破坏要历经裂隙萌生、裂隙扩展、裂隙进一步扩展、贯通破坏阶段。同时当岩溶管道处的过水流量达到初始值(37248m^( 3)/d)约2.7~3.5倍之间时便可出现涌水突泥破坏,也即出水口2流量达到10000~13000m^( 3)/d时,湾潭隧道具有极高的涌水突泥风险。

基于区间数理论的岩溶隧道突水突泥灾害危险评估模型研究

为进一步研究岩溶区隧道突泥涌水灾害分析评价的不确定性和模糊性问题,基于区间数理论、模糊综合评价法以及层次分析法建立岩溶隧道突水突泥灾害危险评估新模型,并从地层岩性条件、地质构造条件、不良地质条件、地形地貌条件、隧道与地下水的位置关系和地下水循环运移条件等影响突水突泥灾害的关键因素出发,建立含有6个一级指标、13个二级指标的评价体系,以期统一刻画区间形式的岩溶隧道突水突泥评价指标的确定性和不确定性,为岩溶区隧道突水突泥区间段落灾害预防与整体评价提供更加实用的解决途径。典型案例对比和实例应用结果表明,该模型评估的岩溶区隧道突水突泥危险等级与案例揭示情况较为吻合,其方法的合理性与实用性得到了验证,计算所得的危险等级较为合理。

隧道涌水突泥风险分级方法及工程应用

隧道涌水突泥具有突发性和严重的破坏性,给隧道施工人员的生命安全造成严重的威胁。为了提高技术人员对涌水突泥的风险管控水平,实现涌水突泥风险的分级管理,通过对隧道通水突泥机理及其影响因素的分析,提出了隧道涌水突泥风险的分级方法。研究结果表明,隧道涌水突泥的风险等级取决于涌水突泥发生的概率等级以及涌水突泥发生后造成的后果等级两个因素;涌水突泥的概率等级取决于地下水水压、水量、围岩破碎及软弱程度、隧道设计施工管理水平等因素。