基于水化学和氢氧同位素的峡口隧道涌水来源识别

峡口隧道是一条位于岩溶山区的深埋特长型隧道,遭遇了历时近两年来源不明的复杂涌水过程。为查明隧道的涌水来源和充水途径,通过解读隧道区的水文地质条件,分析对比不同涌水点的水化学及氢氧同位素组成差异,查明了隧道右洞北侧涌水主要来源于二叠—三叠系岩溶含水层,其他均来自于侏罗系裂隙含水层,二叠系灰岩与泥盆系石英砂岩接触部位发育的岩溶裂隙带为主要的充水途径。     

重庆歌乐山隧址区地下水同位素组成特征及意义

同位素测试作为一种先进的技术手段在地质科学的各个研究领域得到越来越广泛地应用。运用同位素方法研究流体及矿床成因关系方面取得了较大的进展。目前，环境同位素方法被广泛用于识别地下水系统，研究自然界水循环过程和地下水运动规律。不同成因的地下水具有不同的同位素组成特征，而且氢、氧稳定同位素在低温条件下不与围岩发生同位素交换，放射性同位素变化遵循各自的衰变规律，水中HCO3碳、氧同位素组成与被溶解的碳酸盐岩同位素组成有关。在歌乐山隧道施工涌水对周边地下水系统的影响及环境效应评价过程中，取得许多同位素数据，对该区地下水的同位素特征有了新的认识。文章借助同位素方法探讨了隧址区地下水的补给源、年龄等基本特征。该区地下水主要补给来源为大气降水。碳、氧稳定同位素的研究结果也证实了这一点。对放射性同位素氚研究表明，该区地下水年龄基本都较小，属近期大气降水直接渗入补给。     

基于SVM的隧道涌水来源识别

隧道涌水来源识别是隧道涌水预测的前提和隧道水害防治的基础,为向隧道施工和管理等有关部门提供科学参考依据,基于隧道涌水及其可能来源的水化学信息,利用支持向量机（SVM）技术建立了隧道涌水来源识别模型,并以垫邻高速铜锣山隧道进行了实例分析。结果表明,该隧道涌水主要来自区域嘉陵江组和雷口坡组岩溶含水岩系中的地下水,虽有须家河组碎屑岩含水岩系的地下水混入,但在量上不占优,上述结论与隧道地区地表水、井泉水及煤矿水的动态监测结果反映的信息相符,侧面反映出SVM在隧道涌水来源识别应用中具有推广价值。     

秦岭特长隧道地区同位素水文地质研究

氢氧同位素的研究表明，秦岭特长隧道地区地下水可分为浅层风化裂隙水和下部构造裂隙水两类，两者均接受大气降水补给，但前者还接受部分地表水补给，下部水平均补给高度在2100m(岭南）和2200m(岭北）左右，浅层水的循环深度在50m以内，水交替作用强烈；而下部水通常可达800m范围，局部更深，水交替缓慢，同位素质量平衡计算表明，Ⅱ线平行导坑绝大部分集中涌水点的水量主要来自其自身所在下部含水系统的储存量，另一部分来自浅部含水系统地下水的补给量，两者的贡献目前大约分别为66%和34%，综合同位素研究结果，概化出隧址区水文地质概念模型。     

隧道涌水预测方法及防治对策研究

隧道涌水是在隧道建设、运行过程中最为常见的一种工程事故,对于隧道的安全稳定和周边生态环境会产生较大的危害。本文对隧道涌水机理、隧道涌水量预测方法和隧道涌水的防治对策进行研究,认为岩溶地区水文地质条件和隧道开挖、爆破、钻孔等施工活动影响是导致隧道涌水的关键因素。根据地下水运动规律特征,涌水量的预测应采用地下水动力学法,建立计算模型进行推导计算,采取引排方案、泄水洞方案、堆积体加固堵水、绕避方案、注浆堵水等防治措施,从而达到防治的最佳效果。     

雁门关铁路隧道涌水量预测与防护措施研究

雁门关铁路隧道施工范围内地表水及地下水发育,为保证施工安全,应对施工范围内地表水及地下水进行评价,并对施工期的涌水量进行预测。根据水文地质和工程地质调查,结合物探及钻探资料综合分析表明：隧道区域构造发育,断层破碎带导水性好;地下水分布以断层带水和基岩裂隙水为主,一般断层带强富水,而基岩裂隙带为弱富水～中等富水。隧道集中涌水段主要发生在断裂构造发育地带。     

西南某山区高速公路岩溶隧道的涌水灾害危险性研究

西南某山区高速公路越岭岩溶隧道所处区域地质环境条件复杂,全段不仅存在通过岩溶进行地下水近、远程补给而发生涌水突泥的风险,而且勘察发现进口段存在岩溶管道与临近龙湖存在水力联系,存在湖水倒灌的风险。因此,本文以隧道近场区地质建造和构造改造格架为分析物质基础,以地质作用过程机制为分析方法,通过调查、物探及钻探等手段基本查明隧址区环境地质条件,在此基础上建立水文地质原型,对地下水、地表水的补径排关系和渗流场特征,及岩溶空间展布特征展开分析研究,定性到半定量地进行了隧道涌水危险性预测评估,并以评价成果为依据对原隧道平纵布置进行了调整,以进一步降低建设和运营期间的涌水突泥危险性。     

基于水化学及稳定同位素的西藏察雅地下热水成因研究

西藏察雅分布有两处地下热水,其中娘曲热水流量达23 356 m ³/d,温度达36 ℃,掌握其成因以及地下水循环模式对铁路隧道的规划建设具有重要意义。为查明地下热水水化学特征及其成因模式,采用同位素水文地球化学方法进行研究。结果表明:两处地下热水主要阳离子为Ca ²⁺和Mg ²⁺,主要阴离子为SO₄^2-和HCO₃^-,溶解性总固体含量为1 255~2 051 mg/L,水化学类型分别为SO₄·HCO₃-Ca·Mg型和SO₄-Ca·Mg型。氢氧同位素分析结果表明,地下热水补给来源主要为大气降水,并具有 ¹⁸O漂移现象,反映了热水与围岩的氧同位素交换效应。地下热水的补给高程为4 146~4 185 m,热储温度为53.1~61.0 ℃,循环深度为1 409~2 020 m。其成因模式为:地下水在东北部高山区接收大气降水入渗补给,沿岩溶裂隙管道径流,经深循环获得大地热流加热,受构造及岩层阻水影响沿断层上升,在上升过程中与份额达0.79~0.91的浅层地下水混合,于沟谷等地势切割处出露成泉。综合水文地质条件与隧道位置分析,隧道穿越的两处岩溶富水条带,东部岩溶富水区对隧道突涌水威胁较小;西部岩溶富水区对隧道存在构造岩溶水高压突涌水风险,后期应注意防范。     

岩溶地区地下水位变动带隧道涌水问题的思考

通过鸡冠山隧道涌水实例及广泛收集岩溶地区隧道涌水案例,总结出岩溶地区隧道季节变动带涌水具有反应时间快、水量大、泥沙重的特点,并综合分析地下水季节变动带隧道的水文地质特征,将其划分为一般山岭隧道及向斜构造地下水位变动带两种类型,且对两种类型涌水机理进行了阐述。岩溶地区隧道前期勘察应重点划分隧道岩溶地下水系统及地下水动力分带,查明岩溶发育特征与规律;施工期和运行期应结合岩溶揭露情况和涌水情况开展针对性的补充勘察,做好降雨、涌水过程和涌水压力监测,判断和预测最大外水压力和涌水量。针对涌水问题,提出封堵和排泄两种处理思路:施工开挖揭露的岩溶现象不可盲目封堵,需尽可能维持原通道的通畅,针对可能涌水的隧道衬砌设计不可仅考虑围岩结构,应充分考虑外水压力,做好围岩固结灌浆;常规隧道“环形排水系统+中心沟”排水系统可靠性差,针对大流量涌水,多采用泄水洞排水。      

用环境同位素方法研究范各庄煤矿地下水

用环境同位素方法,作者在开滦范各庄地下水调查研究中,确定了主要含水层地下水同位素的背景值;分析和确定了不同含水层之间的水力联系及矿井水中涌水的可能补给来源;计算了矿井二水平主要出水点之混合水比例及不同含水层中地下水平均储留时间。     

包家山隧道地下水动态监测信息的应用研究

隧道地下水动态监测是隧址区地下水环境保护的基础工作,通过对涌水量、涌沙量、隧道内水压力的综合分析,获取隧址区地下水动态监测信息,为隧道的安全运营提供依据。     

石太客运专线特长隧道地区水文地质研究 及隧道开挖环境影响效应*

文章在充分分析已有地质和水文地质资料的基础之上,综合大面积水文地质调绘和多种勘探成果,对石太客运专线太行山隧道和南梁隧道所在区域的水文地质条件进行了系统分析。将隧道区域划分为娘子关泉域系统、威州泉域系统和散泉系统三大地下水含水系统,同时将太行山隧道区划分为5个水文地质单元,将南梁隧道区划分为两个水文地质单元。另外,论述了隧道开挖对地下水和地表水环境的影响,主要表现在对断层或岩脉与隧道相交地段的水位、水量产生影响,这为进一步解决特长隧道施工过程中的突水、涌水等问题提供了可靠的基础性资料,加深了对河北、山西两省交界处水文地质条件薄弱地带的了解。     

Application of fuzzy Delphi AHP method for the estimation and classification of Ghomrud tunnel from groundwater flow hazard

Water inflow and water pressure controls are needed in the design, construction, and exploitation of tunnels. The objective of this paper is to present a new system which can be appropriate for rating tunnel sites to evaluate the potential of groundwater inflow according to the preliminary site investigation data. In this paper, an evaluation model based on combining the analytic hierarchy process and the fuzzy Delphi method has been presented for assessing tunnel site rating from the groundwater hazard point of view. This research treats the tunnel site classification as a group decision problem and applies the fuzzy logic theory as the criterion to calculate the weighting factors. Afterward, the proposed method was successfully applied to determine the amount of groundwater inflow into tunnels. Results of several case studies in various geological conditions roughly show that it can be used to determine the groundwater inflow into tunnels. The introduced method has been examined successfully in Ghomroud tunnel. Results from the proposed method, analytical equations, and observed groundwater inflow into Ghomrud tunnel have been compared. Results show that, because most of parameters regulating groundwater inflow into tunnels have been considered in the method, results from the method are very close to the observed groundwater inflow. Applying this method, according to preliminary investigations conducted by the designers, provides a more suitable design of the drainage system, drilling method, and tunnel support.     

大庆-哈尔滨地段地热资源研究

作者应用地下水系统理论,从古水文地质条件及现代地下水动力场特征入手,通过水文地球化学和环境同位素地球化学研究,探讨了松辽盆地中段的地热及其赋存特征,认为盆地的大部分地区温梯度都较高,具有形成深部地热的条件,但只在上部具有较厚的含水层及断裂发育凹陷带中的局部地区,才能赋存可开采的地下热水资源。     

Influence of rock mass properties on tunnel inflow using hydromechanical numerical study

One of the primary geotechnical problems encountered during tunnel construction involves the inflow of groundwater into the tunnel. Heavy inflows make tunnel construction difficult and result in higher costs and delays in construction period. Therefore, it is essential to estimate the volume and rate of water inflow that is likely to appear in the tunnel. In this research, water inflow to the tunnel was calculated using numerical hydromechanical analysis. Effect of rock mass properties including fracture characteristics (normal and shear stiffness, hydraulic aperture, dilation angle, and fracture nonlinear behavior) on inflow was studied using a two-dimensional distinct element method. Results show that fracture properties play important role in inflow to the tunnel and must be considered in prediction of inflow to the tunnel. Based on numerical analysis results, inflow of groundwater into the tunnel increases with the increasing of normal and shear stiffness, dilation angle, and hydraulic aperture of rock mass fractures. The measured inflow with considering nonlinear fracture behavior was more than the calculated inflow with linear constitutive behavior.     

Effect of Excavation-Induced Groundwater Level Drawdown on Tunnel Inflow in a Jointed Rock Mass

Analytical and empirical methods used in current engineering practice for estimating inflow rate into a tunnel do not adequately account for the effect of groundwater level drawdown which triggers changes of the flow pattern as well as reductions of the hydraulic head. When there is no reservoir or a large body of water near the tunnel alignment, the groundwater recharge above the tunnel might not be fast enough to avoid a significant excavation-induced water level drawdown. This paper provides analytical methods for estimating groundwater inflow rate taking into account the groundwater table drawdown. The proposed analytical solutions presented here compare well with field observations as well as with results from numerical analysis using distinct element method which can adequately simulate the hydro-mechanically coupled behavior of joints in a rock mass.     

Prediction of water inflow to mechanized tunnels during tunnel-boring-machine advance using numerical simulation

An accurate estimate of the groundwater inflow to a tunnel is one of the most challenging but essential tasks in tunnel design and construction. Most of the numerical or analytical solutions that have been developed ignore tunnel seepage conditions, material properties and hydraulic-head changes along the tunnel route during the excavation process, leading to inaccurate prediction of inflow rates. A method is introduced that uses MODFLOW code of GMS software to predict inflow rate as the tunnel boring machine (TBM) gradually advances. In this method, the tunnel boundary condition is conceptualized and defined using Drain package, which is simulated by dividing the drilling process into a series of successive intervals based on the tunnel excavation rates. In addition, the drain elevations are specified as the respective tunnel elevations, and the conductance parameters are assigned to intervals, depending on the TBM type and the tunnel seepage condition. The Qomroud water conveyance tunnel, located in Lorestan province of Iran, is 36 km in length. Since the Qomroud tunnel involved groundwater inrush during excavating, it is considered as a good case study to evaluate the presented method. The groundwater inflow to this tunnel during the TBM advance is simulated using the proposed method and the predicted rates are compared with observed rates. The results show that the presented method can satisfactorily predict the inflow rates as the TBM advances.     

Analytical approach for time‐dependent groundwater inflow into shield tunnel face in confined aquifer

Prediction of time‐dependent groundwater inflow into a shield tunnel is a significant task facing engineers. Published literature shows that there is no available method with which to predict time‐dependent groundwater inflow into a tunnel. This paper presents a prediction approach for time‐dependent groundwater inflow into a tunnel in both anisotropic and isotropic confined aquifers. The proposed solution can predict groundwater inrush from the tunnel cutting face. To obtain the time‐dependent groundwater flow quantity, the concept of a horizontal‐well pumping test based on the theory of a point source is adopted. Multiple factors, eg, drawdown, thickness of aquifer, conductivities, and specific storage, are taken into account. Both groundwater inflow to the cross section of a tunnel face in the y‐z plane and total tunnel inflow are obtained. Based on the proposed approach, the time‐dependent groundwater inflow to a tunnel can be classified as either a uniform or non‐uniform flow. The proposed approach is applied to analyse groundwater inflow of 2 field cases: (1) Metro line No. 7, Guangzhou City and (2) an underground tunnel in Huizhou, Guangdong Province. Results show that the proposed method can predict the measured values, and drawdown‐related curves are also derived. In addition, the calculated results also reveal that the effect of hydraulic conductivity k_z on the total groundwater inflow differs from that of hydraulic conductivities k_x and k_y and the thickness of the aquifer.     

银北平原浅层高砷地下水砷富集水化学特征研究

宁夏银川平原是继河套平原之后,在黄河流域发现的又一个高砷地下水分布区.为了总结其高砷地下水的水化学特征,并探索水化学因素对地下水砷释放和富集的影响机制,本文以银川平原北部（银北平原）作为典型研究区,采取野外水文地质调查、水样采集与测试、砷与水化学组分散点图相关分析及水文地球化学方法进行了综合研究.结果表明,银北平原地下水砷含量在0.2~177 μg/L之间;高砷地下水（大于50 μg/L） pH值多在7.5~8.5,水化学类型主要为HCO3-Na·Ca、Cl·HCO₃-Na及Cl·HCO₃-Na·Ca型,E_h多在-200~-100 mV.银北平原砷含量较高的地下水中COD、NH₄⁺、HCO3^-含量相应也较高,而NO3^-和SO₄^2-含量较低.高砷富有机质的冲-湖积含水层经过长期演化,形成偏碱性的中强还原性地下水环境和特殊的水化学特征,也具备极大的砷释放能力.较高的pH导致砷从铁锰氧化物或氢氧化物等水合物或黏土矿物表面解吸.其次部分铁锰氧化物在高pH、低E_h条件下可被还原为低价态可溶性铁锰,从而使与其结合的砷也得以释放进入地下水中.此外重碳酸根与砷酸根、亚砷酸根的竞争吸附行为促使含水层砷的解吸.     

山东文登抽水蓄能电站尾水洞段地下水连通性的环境同位素和水化学研究

基于对分布于山东省文登地区黑豹泉地下水子系统（Ⅰ2）及其相邻的六度寺沟地下水子系统（Ⅰ1）和苇夼沟地下水系统（Ⅱ）内的11个水样品的3H（D,氘）、2H（T,氚）、18O同位素和水化学成分的分析结果,对文登抽水蓄能电站尾水洞段地下水的连同性进行了研究。研究结果表明,黑豹泉地下水子系统（Ⅰ2）及其相邻的六度寺沟地下水子系统（Ⅰ1）和苇夼沟地下水系统（Ⅱ）内的地下水特征在环境同位素和化学成分方面都具有明显的差异,具有各自的补、径、排条件。尤其是在黑豹泉地下水子系统（Ⅰ2）内,以F12断层为边界,其南部和北部两个区域的地下水的特征,不具有相似性,故二者之间的水力联系不密切,表明F12断层为阻水断层。同时,利用数值方法和泉域水均衡方法结果表明探洞的开挖对该区的地下水位变化的影响不太大。但是由于该区是一个四周由隔水边界组成的相对封闭体系,除大气降水外无其他固定的汇水源头。因此,在长时间内,不采取任何措施的情况下,水位将会继续下降。