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.

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 electromagnetic methods for the detection of the hidden danger of water gushing at the coal face were introduced. Also, emphasis was laid on expounding the methods, principles and effects of down-hole detections by electric transmission tomography and transient electromagnetic method. The potential of point power supplied in the underground homogeneous semi-space, as well as the response to a low-resistivity abnormal body in the homogeneous semi-space, was simulated by adopting 3-D finite element method to interpret the basic theory of the electric transmission tomography. The results of actual measurement show that the mine electromagnetic method is sensitive to water-bearing low-resistivity bodies and can play a unique role in detecting the hidden danger of water gushing at the coal face.

Theory and application of infrared surveying gas gushing technology in coal-rock roadway

Geological structure and gas expansion when gas pressure was released can affect the distribution of infrared radiation energy or temperature at coal rock surface. From this, the foundation of roadway infrared surveying technical was formed. According to the thermodynamic principle of ideal gas and the law of energy conservation, the relation was established between gas gushing amount from coal rock and air temperature to fall in roadway. At the same time, this paper has analyzed coal rock density change that geological structure aroused and the change exerted influences on infrared radiation power at surface, as well as, has analyzed the infrared radiation feature of gas gushing at geological structure district. Application results show that infrared survey technology can be used to analyze and forecast the change of coal rock gas gushing effectively, and to guide the enforcement of the roadway gas project of prevention and handling economically.

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.

A Regional-Scale Method of Forecasting Debris Flow Events Based on Water-Soil Coupling Mechanism

A debris flow forecast model based on a water-soil coupling mechanism that takes the debrisflow watershed as a basic forecast unit was established here for the prediction of disasters at the watershed scale.This was achieved through advances in our understanding of the formation mechanism of debris flow.To expand the applicable spatial scale of this forecasting model,a method of identifying potential debris flow watersheds was used to locate areas vulnerable to debris flow within a forecast region.Using these watersheds as forecasting units and a prediction method based on the water-soil coupling mechanism,a new forecasting method of debris flow at the regional scale was established.In order to test the prediction ability of this new forecasting method,the Sichuan province,China was selected as a study zone and the large-scale debris flow disasters attributable to heavy rainfall in this region on July 9,2013 were taken as the study case.According to debris flow disaster data on July 9,2013 which were provided by the geo-environmental monitoring station of Sichuan province,there were 252 watersheds in which debris flow events actually occurred.The current model predicted that 265 watersheds were likely to experience a debris flow event.Among these,43 towns including 204 debrisflow watersheds were successfully forecasted and 24 towns including 48 watersheds failed.The false prediction rate and failure prediction rate of thisforecast model were 23% and 19%,respectively.The results show that this method is more accurate and more applicable than traditional methods.

Pore pressure fluctuations of overlying aquifer during residual coal mining and water-soil stress coupling analysis

Three test models and a simulation model were constructed based on the prevailing conditions of the Taiping coalmine in order to analyze pore pressure fluctuations of an overlying aquifer during residual coal mining. As well, the relation between pore pressure and soil stress was evaluated. The model tests show the vibrations of pore pressure and soil stress as a result of mining activities. The simulation model tells of the response characteristics of pore pressure after mining and its distribution in the sand aquifer. The comparative analysis reveals that pore pressure and soil stress vibration are activated by unexpected events occurring in mines, such as collapsing roofs. An increased pore pressure zone always lies above the wall in front or behind the working face of a mine. Both pore pressure and vertical stress result in increasing and decreasing processes during movements of the working face of a mine. The vibration of pore pressure always precedes soil stress in the same area and ends with a sharp decline. Changes in pore pressure of sand aquifer are limited to the area of stress changes. Obvious changes are largely located in a very small frame over the mining face.

Simulation of Water-Soil-Structure Interactions Using Incompressible Smoothed Particle Hydrodynamics

In the present work,an incompressible smoothed particle hydrodynamic(SPH)method is introduced to simulate water-soil-structure interactions.In the current calculation,the water is modelled as a Newtonian fluid.The soil is modelled in two different cases.In the first case,the granular material is considered as a fluid where a Bingham type constitutive model is proposed based on Mohr-Coulomb yield-stress criterion,and the viscosity is derived from the cohesion and friction angle.In addition,the fictitious suspension layers between water and soil depending on the concentration of soil are introduced.In the second case,Hooke’s law introduces elastic soil.In ISPH,the pressure is evaluated by solving the pressure Poisson equation using a semi-implicit algorithm based on the projection method and an eddy viscosity for water is modelled by a large eddy simulation with the Smagorinsky model.In the proposed ISPH method,the pressure is stabilized to simulate the multiphase flow between soil and water.Numerical experiments for water-soil suspension flow of Louvain erosional dam break with flat soil foundation,is simulated and validated using 3D-ISPH method.Coupling between water-soil interactions with different solid structures are simulated.The results revealed that,the suspension layers with the Bingham model of soil gives more accurate results in the experiment as compared to the case of the Bingham model without suspension layers.In addition,the elastic soil model by the Hooke’s law can simulate soil hump accurately as compared to the Bingham model.From the simulations,avoiding erosion behind the structure for preventing the structure break during flood are investigated by using an extended structure or a wedge structure.

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。

2023年甘肃积石山M_(S)6.2地震中川乡泥流成因及破坏性分析

2023年12月18日23时59分,甘肃临夏州积石山县发生6.2级地震,并诱发了大量地质灾害,其中,中川乡砂土液化泥流灾害造成了重大的经济损失与人员伤亡,亟需对其特征、成因、破坏性进行分析厘定。根据已有文献资料,利用获取的高精度、高分辨率数字成果,借助影像解译、地面调查,对震后泥流灾害进行综合分析。结果表明:(1)易滑且饱水黄土在地震的震动载荷作用下,土体内孔隙水压力迅速升高导致砂土液化,最终土层失稳破坏,导致台地边缘垮塌与地震滑坡。土水混合物在重力作用下,顺着高差沿沟谷、冲沟前进形成液化型滑坡-泥流灾害。(2)此次灾害现象并非泥流单一作用,而是砂土液化导致的泥流和砂涌同时存在,二者同时发生的概率很低,破坏性极大。(3)此次地震为典型的“小震、中震大灾”情况,相比其他相似成因液化滑坡灾害,其规模更大;相比其他相近震级地震,其造成的破坏及伤亡更大。此次地震诱发的地质灾害具有一定的特殊性与异常性。

高抽巷预抽采工作面爆炸危险性研究

高抽巷预抽采工作面对煤矿生产的稳定性和经济效益至关重要。然而,由于其存在爆炸危险性,研究工作面的爆炸危险性具有重要意义。瓦斯爆炸需要满足3个条件:瓦斯爆炸界限、引火温度和氧气浓度。为了研究工作面的爆炸危险性,对余吾煤业采用了高抽巷抽采的工作面进行了气体监测实验,并测量了瓦斯回采期间工作面和高抽巷的瓦斯涌出规律。实验结果显示,余吾煤业工作面氧气浓度和瓦斯浓度均符合爆炸条件。通过探究工作面瓦斯涌出规律,发现可以通过调整工作面推进度来改变高抽巷的瓦斯浓度。因此,高抽巷预抽采的工作面在氧气和瓦斯方面均能满足爆炸要求,并可通过调整推进度来降低瓦斯浓度,减少瓦斯爆炸的可能性,为煤矿生产安全提供了参考。

香炉山隧洞不良地质段“L”型地面超前注浆方案研究

为解决隧道(洞)建设过程中不良地质段突泥涌水和软岩大变形等问题,依托滇中引水工程香炉山隧洞,提出一种采用全孔长度超过500 m的地面“L”型定向钻孔注浆并辅以洞内超前注浆的加固方法,在实际工程中确定这一方法的具体设计方案。首先,通过现场地质调查与分析,揭示不良地质区段香炉山隧洞建设的技术难点;其次,介绍“L”型定向钻孔注浆的施工过程及注浆工艺;然后,设计出一种能够提高地层稳定性的“L”型地面超前注浆方案,并对地层进行加固;最后,采用掌子面揭示、注浆技术以及大地电磁检测等手段证明现场注浆效果。研究结果表明:1)“Z1+Z2+Z4”钻场设计为最优地面超前注浆技术方案;2)“L”型定向钻孔注浆辅以洞内超前注浆技术可满足盲区注浆区域覆盖问题,实现真正意义上的超前治理。

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。

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。

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。

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。

山区高速公路隧道施工中涌水预测与涌水方案研究

随着高速公路隧道施工的不断发展,地下水控制与涌水管理成为确保施工安全和顺利进行的关键因素。通过对地下水特性及隧道施工中涌水预测;影响因素以及预测方法的综合分析,探讨了高速公路隧道施工中的涌水预测方案的选择。文中回顾了过往研究,识别了现有问题,并提出防水屏障技术作为地下水控制的方法,虹吸排水方法对隧道涌水的运用。通过实际工程案例的分析,总结了排水方法的效果与经验。最后,展望了未来技术创新和可持续性考虑在高速公路隧道施工中的应用。该研究为喀斯特地貌山区高速公路隧道施工中地下水控制提供了深入的理论和实践参考。

鸿图特长隧道高压涌水成因分析

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