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.

Application of SVM in Analyzing the Headstream of Gushing Water in Coal Mine

To recognize the presence of the headstream of gushing water in coal mines, the SVM (Support Vector Ma- chine) was proposed to analyze the gushing water based on hydrogeochemical methods. First, the SVM model for head- stream analysis was trained on the water sample of available headstreams, and then we used this to predict the unknown samples, which were validated in practice by comparing the predicted results with the actual results. The experimental results show that the SVM is a feasible method to differentiate between two headstreams and the H-SVMs (Hierachical SVMs) is a preferable way to deal with the problem of multi-headstreams. Compared with other methods, the SVM is based on a strict mathematical theory with a simple structure and good generalization properties. As well, the support vector W in the decision function can describe the weights of the recognition factors of water samples, which is very important for the analysis of headstreams of gushing water in coal mines.

Numerical simulation of groundwater under complex karst conditions and the prediction of roadway gushing in a coal mine:a case study in the Guang'an Longtan Reservoir in Sichuan Province, China

Numerical simulation of groundwater in karst areas has long been restricted by the difficulty of generalizing the hydrogeological conditions of reservoirs and of determining the relevant parameters due to the anisotropy and discontinuity of the karst water-bearing media in these areas. In this study, we used the Guang'an Longtan Coal mine in Sichuan as an example, and generalized the complex hydrogeological conditions in the reservoir area. A finite element numerical flow model was used to simulate current and future scenarios of roadway gushing at the bottom of the coal mine at pile number 1 + 700 m. The results show that the roadway section corresponding to valleys has a gushing quantity of 4323.8–4551.25 m^3/d before impoundment. Modeled water inflow after impoundment increased to 1.6 times the water inflow before impoundment, which threatens the impoundment as well as the roadway's normal operation. Therefore, roadway processing measures are needed to guarantee the safety of the impoundment and of the mining operation.

Physico-Chemical Characteristics of Gushing Water Aquifers in the Coastal Sedimentary Basin of Benin (West Africa)

The coastal sedimentary basin in southern Benin consists of monoclinal layers divided into two plateau zones (North and South) which are separated by a longitudinal depression ESE-WNW. The valleys of the main N-S-oriented rivers (Ouémé, Couffo and Mono) set the bondaries of the different plateau of the BSC (Coastal Sedimentary Basin). The present study, based on geology, hydrochemistry, temperature and log data available on boreholes, makes a physico-chemical characterization of the waters of the gushing aquifers of the coastal sedimentary basin of Benin. The gushing water boreholes are shared between the valleys of the main rivers of the BSC. Some of these boreholes are thermal with a water temperature between 38 and 69 degrees Celsius. The hydrogeological correlations established in the BSC in accordance to the North- South direction in the valleys of the main streams (Couffo and Ouémé) reveal that the captured aquifers are sands, marls and limestones that respond either in major discordance (northern zone) or above the sedimentation gaps (southern zone). Chemical analyses have shown that gushing thermal waters are mineralized in the south with a neutral to basic pH and are highly concentrated with bicarbonate, calcium and magnesium ions. In the North, on the other hand, thermal waters are acidic with a pH ranging from 4.8 to 5.9. The acidic nature of the northern waters is influenced by the crystalline base while the southern neutral to basic waters are influenced by the lithological nature (limestone and marl) of the aquifer. The random distribution of thermal water boreholes in the valleys of the main BSC streams is believed to be related to tectonic events.

Detection technology and application of electromagnetic method for hidden danger of water gushing at coal face

The principles,methods,technologies and application effects of several electromagneticmethods for the detection of the hidden danger of water gushing at the coalface were introduced.Also,emphasis was laid on expounding the methods,principles andeffects of down-hole detections by electric transmission tomography and transient electromagneticmethod.The potential of point power supplied in the underground homogeneoussemi-space,as well as the response to a low-resistivity abnormal body in file hemogeneoussemi-space,was simulated by adopting 3-D finite element method to interpretthe basic theory of the electric transmission tomography.The results of actual measurementshow that the mine electromagnetic method is sensitive to water-bearinglow-resistivity bodies and can play a unique role in detecting the hidden danger of watergushing at the coal face.

岩溶凹陷式露天矿山大流量涌水治理技术

我国岩溶地质分布广泛,岩溶突涌水已成为石灰石矿山安全生产的巨大灾害与挑战。以广西某岩溶凹陷式露天矿山大流量涌水为研究对象,针对该矿山地质条件复杂、集中涌水量大、流速高等特点,利用岩溶发育特征、资料分析与地球物理探查等方法初步圈定矿山径流带区域;进一步通过钻探、跨孔CT和示踪联通试验等精准查找到矿山Y01特大涌水点岩溶管道的具体位置,在此基础上研究并实施了矿山涌水治理技术与工艺。研究表明:(1)针对复杂岩溶凹陷式露天矿山大流量、高流速的涌水特征,提出并实施了“非连续帷幕截流+关键通道探查与封堵+止浆垫控流降速”的岩溶矿山涌水综合治理体系。依据岩溶发育的不均匀性,提出了非连续帷幕封堵裂隙型涌水区域的思想;对大流量岩溶管道型集中涌水设计采用止浆垫控流装置,通过控流能有效降低关键过水通道内水流速度,为注浆材料的有效留存沉积和工程的成功封堵提供了重要条件。(2)关键孔联合注浆工艺是岩溶管道型涌水成功封堵的保证,关键孔是指直接揭露岩溶涌水管道或与涌水管道联通性极强并对注浆堵水起主要作用的钻孔。针对矿山Y01岩溶管道型特大涌水精准查找到2个关键孔,均在矿坑南部:一个是距涌水点直线距离约50 m的近距离钻孔(以下简称“近孔”),另一个是距涌水点直线距离约150 m的远距离钻孔(以下简称“远孔”)。现场采用近孔、远孔2个关键孔联合注浆工艺:近孔以粗骨料和自主研发的可控凝结新型材料进行注浆,远孔仅注水泥浆液;近孔粗骨料和新型材料既能降低管道内的水流速度为远孔浆液起到更好的留存沉积作用,又能作为封堵材料起到增强的功能,远孔因其离涌水点距离长、辐射范围广、浆液扩散充分而能确保封堵长度和效果。近孔、远孔协同配合同步注浆是封堵管道型大流量涌水的有效组合工艺。(3)涌水口止浆垫控流降速装置的合理有效调控,配合关键孔联合注浆工艺的同步实施,进一步确保了注浆浆液的有效快速留存和沉积,是岩溶地区封堵管道型大流量涌水的创新性技术和方法。项目实施后,彻底封堵矿坑内集中涌水量达7.12万m^(3)/d的Y01特大涌水点,实现总减水量8.43万m3/d(含非连续帷幕注浆封堵),保证了矿山的正常安全开采,大幅降低了抽排水费用,同时保护了周边环境和地下水资源,具有显著的经济效益和社会效益。研究成果可为我国矿山涌水灾害治理提供理论价值和经验借鉴。

骨架颗粒组成对散粒土管涌规律影响的试验研究

利用改进的渗透装置试验研究了细颗粒(0.075~1 mm)含量相同时骨架颗粒组成含量不同对散粒土的管涌发生临界条件以及颗粒侵蚀流失规律的影响,结果表明:不同颗粒级配的试样在管涌发生前,水力梯度与渗流速度呈线性关系,基本符合达西定律;骨架颗粒1~2、2~3、3~5 mm 3个粒径段对管涌发展起到了阻碍作用,其中1~2 mm粒径段颗粒对管涌孔隙的堵塞作用强于另外两个粒径段颗粒;对于不同级配的骨架颗粒,其不均匀系数越大,试样的下限临界水力梯度值就越大,细颗粒越不易起动,发生管涌的时间越晚,而不同级配的骨架颗粒对试样的上限临界水力梯度影响较小。

富水区隧道穿越断层破碎带施工应急预案研究

为降低富水区公路隧道穿越断层破碎带施工中涌水、塌方等突发事件的危害,保证施工人员的安全,该文依托古兜山隧道实体工程,建立富水区隧道施工中突发事件应急预案体系。对富水区公路隧道穿越断层破碎带施工过程中可能的突发事件进行分类,建立富水区隧道突发事件应急预案。研究表明,富水区隧道施工过程中发生涌水事故时,应及时疏通横通道,布设抽水泵将涌水抽出洞外,减少洞内水流量;出现坍塌事件时,应当及时处理伤亡人员,并及时运走废土;发生爆炸事故时,应迅速灭火及时疏散工作人员,救治伤员,清理现场,避免造成二次伤害;发生大型机械设备故障情况后,要及时处理伤亡人员,并尽快判断其位置和损伤范围,及时开展救援,转移机械设备,抢修故障机械。

安定组地层渗透性变化下的覆岩白垩系含水层涌水规律研究

为了研究呼吉尔特矿区某深埋矿井煤层开采对地下含水层的影响,采用地下水三维数值模型对大采高深埋煤层开采过程中地下水流场的变化进行模拟研究。模拟结果显示,煤层开采对顶板白垩系含水层及侏罗系直罗组含水层流场均产生较大影响,工作面开采过程中安定组地层渗透系数发生改变,使其隔水性能产生变化,上覆白垩系含水层参与井下涌水程度随之改变,导致工作面涌水量呈阶梯状变化趋势。由于白垩系含水层富水性强于直罗组含水层,白垩系含水层依然是工作面的主要涌水来源,其贡献度达到70.4%。该结果可为呼吉尔特矿区深部大采高煤层的防治水重点提供依据。

富水白云岩斜井注浆堵水技术应用研究

针对昆阳磷矿二矿胶带斜井开拓过程中遇到的水害问题,运用地质雷达和探水孔对巷道围岩的富水情况进行超前探测,查明了巷道围岩的破碎程度和富水特征,根据富水性探测结果,针对性地制订注浆堵水方案,由于巷道围岩属于节理裂隙发育的硬质岩,弱富水破碎带设计采用水泥注浆,强富水破碎带设计采用马丽散E化学注浆。在现场开展注浆试验,通过对比注浆前后的单孔涌水量和区段涌水量来评估注浆堵水效果,试验结果表明:化学浆液渗透性好,凝固时间短,平均堵水效率为76.6%,水泥-水玻璃浆液则为70.5%;通过对工作面分区段预注浆,能有效封堵涌水通道,改善工作环境和围岩条件,优化支护设计,每米支护成本降低了20%。研究成果可为类似地质条件下的巷道水害治理提供参考。

富水粉细砂隧道失稳破坏特征分析及增稳固结技术研究

桃树坪隧道穿越富水粉细砂地层,施工过程中极易出现大变形、涌水涌砂和坍塌等一系列破坏特征。通过对隧道失稳破坏的分析,总结了隧道在富水粉细砂条件下失稳破坏的特征,分析了破坏特征发生的机制,认为隧道的破坏主要由围岩岩性和地下水造成;由隧道破坏机理提出了增稳固结措施,通过超前降水、超前小导管注高分子化学浆对掌子面前方砂层进行预先固结,提高钢架整体刚度,通过对扰动砂层进行灌浆和回填等措施进行固结,围岩的自承能力得到提高。从处理后围岩的情况、涌水量和监测情况分析发现,增稳固结技术能从根本上提高围岩的自承能力,抑制发生失稳破坏,为隧道在富水粉细砂地层中的施工提供借鉴。

碎软煤层定向钻孔防瓦斯套铣打捞技术

针对碎软煤层定向钻孔套铣打捞,孔壁失稳塌孔造成瓦斯异常涌出的技术难题,提出了碎软煤层定向钻孔防瓦斯套铣打捞技术。在现有套铣打捞技术基础上,分析了碎软煤层套铣打捞孔内瓦斯异常涌出原因、涌出通道和涌出量,优化了套铣打捞钻具内抽采瓦斯管路系统,将套铣打捞过程中打捞钻具内积聚瓦斯进行抽采并卸压;开发了套铣打捞孔口密闭抽瓦斯系统和套铣打捞加杆防瓦斯装置,实现套铣打捞全程负压抽采、密闭排渣和密封加杆。利用该技术成功处理1起孔深362 m的碎软煤层定向钻孔卡钻事故,事故处理中通过打捞钻具内抽采瓦斯管路系统,实现了打捞钻具内积聚瓦斯的抽采和卸压,通过孔口密闭抽瓦斯系统和加杆防瓦斯装置,实现了孔口和打捞钻杆末端口涌出瓦斯的密闭抽采,整个打捞过程中未发生瓦斯超限事故。

玉磨铁路新平隧道突涌致灾机理及措施响应研究

为查明玉磨铁路新平隧道突涌的致灾机制,结合隧道现场灾害特征,基于地形地貌、地层岩性、地质构造、水文地质、气候条件、施工措施等因素,探讨了突涌的致灾机理,归纳总结了隧道突涌的致灾类型,提出了相应的灾害防控措施。软岩隧道强度低、变形大,设计围岩级别与揭示不匹配等因素对隧道灾变的发生至关重要,特殊的构造环境及地下水等因素助推了灾变的发生;依据致灾成因,将该隧道致灾类型分为:构造-岩性-富水-施工措施,构造-岩性-弱水-施工措施,岩性-富水-施工措施等3种类型,并提出了相应的防治措施;施工过程中,需明确可能致灾的几类因素,加强超前地质预报、监控量测、开挖揭示比对等工作,掌控灾害源的发展及规模,动态调整隧道致灾的类型,针对性地采取防控措施,确保隧道施工安全。

博乐盆地石炭系地层“涌水携气”现象与页岩气成藏模式探讨

为了搞清博乐盆地石炭系地层“涌水携气”现象与页岩气成藏模式,根据录井数据分析和现场岩芯观察,结合盆地构造演化特征、烃源岩地化特征、含气性特征、地层压力特征对该现象成因进行了分析,进而对博乐盆地页岩气气藏聚集模式进行了探讨,研究认为在博乐盆地页岩气具有裂缝型和原地型2种成藏模式,其中裂缝型成藏的页岩气主要来源于有机质含量较高的烃源岩生烃,通过开启性断层和裂隙的沟通运移而来,而自身TOC含量一般较低,气藏中以游离气为主,“涌水携气”现象是裂缝型气藏的具体表现。原地型成藏是在盆地中心附近由于烃源岩本身具有较好的生烃条件,生成的页岩气未发生明显运移在原地自生自储,TOC含量控制气藏分布与规模。综合分析2种模式来看,裂缝型气藏模式具有成本低、勘探难度较小,易于实施等优势,是博乐盆地页岩气下一步勘探寻找的方向。

小纪汗煤矿井下涌水余热资源回收利用研究

针对小纪汗煤矿目前供热方案绿色环保性不足的问题,提出利用热泵技术,对小纪汗煤矿地下涌水余热及空压机余热进行回收利用,实现资源的循环。对构建的供热改造方案进行应用效果分析,结果显示,该方案全年运行费用为922.7万元,供热调节率10%~100%,热效率为330%~450%,不仅能够提高供热效率和绿色环保性,还能降低运行费用,简化人员配置,有利于矿区的可持续发展,提高经济效益。

高黎贡山某公路隧道施工对地下水及地表植被的影响研究

横断山南段高黎贡山国家级自然保护区水文地质条件复杂,为研究此区域某公路隧道掘进对地下水环境和地表植被的影响,在隧址区工程地质勘察和自然植被垂直分布、植物多样性调查的基础上,采用地下水动力学法计算出隧道施工地下水影响半径、最大和正常涌水量,据此分析隧道涌水造成的漏失对地下水环境、高黎贡山自然保护区植被生长及植物多样性的影响。结果表明:1)隧道施工对隧址区局部和个别泉点水量减小的风险较大,间接影响其补水区域地表植被生长,但不会引起大范围区域地下水位下降;2)通过类比分析得出隧道施工不会影响到顶部地表浅层包气带,对顶部植被优势群系非耗水植物影响小。根据研究结果提出了隧道涌水预判、封堵、利用及生态监测等环境保护措施建议,可作为隧道施工过程中地下水和生态环境保护的依据。

复杂地质盾构始发工作井围护结构施工关键技术

深圳至惠州城际大鹏支线的坪山至燕子湖区段,地质复杂,工程难点包括基坑涌水砂、深坑挖掘、土层稳定性及岩层影响。面对挑战,提出相关措施包括质量与防水控制、挖掘效率优化、稳定性监测及支护,以及提升岩层挖掘安全性,确保施工安全高效,顺利完成。

管棚法支护在富水层沙土地质深基坑支护工程中的应用

结合某建筑工程,针对其存在突涌、流沙以及地下构筑物及周边建筑物变形较大的问题,采用管棚法对深基坑进行支护,主要围绕该技术的原理、施工要点、施工质量及安全控制措施进行探讨,并对施工经济效益进行分析,最终得出结论:管棚支护法具有经济、高效的优点,用在深基坑支护中可取得较好的社会效益和经济效益。

新近系软岩隧道涌砂机理和防控技术研究

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