千岛湖配水工程隧洞超前预报中的综合物探技术

将TSP、探地雷达及红外探测技术用于千岛湖配水工程隧洞超前预报中,结果如下:TSP对溶洞的探测分辨率低,对岩体破碎区探测效果较好,其异常特征表现为杨氏模量、密度及纵波波速偏低;探地雷达很适合于灰岩区隧洞超前预报,雷达反射剖面呈现强振幅及双曲线状同相轴的区域预示溶洞发育;红外探测受隧洞喷混凝土水化热干扰影响巨大,无法单独用于隧洞地质预报,当围岩质量级别较差时此缺陷尤为明显。     

下穿填埋场隧道综合超前预报与防控措施研究

深圳坂银通道鸡公山隧道的设计路线下穿了深圳下坪固体废弃物填埋场,由于钻孔分析等前期地质勘察无法在该区域开展,下穿填埋场隧道区段施工存在地质状况不明、填埋场渗滤液及填埋气泄露等风险,现有隧道施工超前预报体系不适用于隧道下穿填埋场引发环境灾害问题。针对该难题,本文基于地震预报法(TGP)、瞬变电磁法(TEM)、超前钻孔、取样化学分析等多种方法,构建了隧道下穿填埋场施工超前地质预报体系,并对下穿填埋场隧道区段的围岩质量和渗滤液、填埋气渗漏情况进行了探测与综合分析。结果表明:(1)综合超前预报方法能够提高隧道前方围岩级别判定准确性;(2)填埋场下方存在联通至隧道施工区域的潜在渗滤液渗流通道,但尚未有渗滤液下渗情况发生,隧道开挖过程也无有毒有害气体逸出;(3)针对渗滤液渗漏风险隧道区段,采取全包防水和提升防渗材料等级等方式,可有效保障隧道施工与运营安全。本文研究成果可为隧道穿越环境风险区域施工的超前预报工作提供参考借鉴。     

莲花隧道软弱围岩大变形预测方法适用性评价研究

评估地质条件以及开挖风险是地下空间设计和施工中的重要阶段之一。在选择合适的开挖方法和支护系统时,识别和估计岩体的变形潜在趋势非常重要。在本研究中,对萍莲高速莲花隧道中的岩体变形潜在趋势进行了研究。首先介绍了莲花隧道的工程地质环境、隧道围岩工程特性、岩体质量评价以及现场实测的隧道变形情况,然后运用经验法和半经验-半理论法预测莲花隧道变形趋势,并将预测结果与实际变形监测情况进行对比。结果表明,莲花隧道的大变形主要受松散破碎、遇水膨胀的软弱围岩和丰富的地下与地表水以及断层破碎带与构造活动的影响。对于莲花隧道而言,现行大变形预测方法普遍存在一定问题：经验法主要依据岩体质量分级结果进行变形趋势预测,具有一定的主观性,其预测结果与实际变形情况存在一定偏差;半经验-半理论方法中运用围岩强度与应力关系进行预测效果较好,但基于围岩强度应力比的Jethwa法、Hoek法与ISRM法预测结果偏保守,且针对无变形段的预测效果较差。综上所述,在工程勘察与设计阶段,应客观、细致地进行围岩质量分级、地应力量测、地下水与地质构造勘探等工作,结合经验法、半经验-半理论方法对大变形趋势和变形量值进行预测,综合研判隧洞沿线...     

深埋高地应力隧道勘察期岩爆烈度概率分级预测

岩爆是地下工程开挖过程中硬质岩体存储的弹性应变能突然、迅速释放的动态过程。我国西南山区正在建设或拟建大量深埋长大隧道,勘察阶段岩爆的准确预测对有效设计和控制投资十分重要。从隧道工程勘察阶段线路比选与设计需求出发,针对隧道勘查期岩爆灾害预测指标获取难、预测精度低的问题,以该阶段岩爆预测指标的易获取性为前提,利用贝叶斯网络解决不确定性问题的有效性来反映岩爆烈度与各影响因素的相关关系。基于473组岩爆灾害案例,采用4个预测指标（地应力、地质构造、围岩级别和岩石强度）来构建岩爆烈度朴素贝叶斯概率分级预测模型,利用十折交叉验证方法确定模型预测精度达84.47%。将该模型应用于雅安—叶城高速公路跑马山1号隧道岩爆段落,预测结果显示:28次岩爆预测中有24次正确、4次错误,准确率高达85.71%;其中2组错误预测中,现场判别为轻微-中等岩爆,而本文模型预测为轻微岩爆。验证结果表明所建立的贝叶斯网络模型具有良好的预测性能,研究成果可为我国西南山区深埋长大硬岩隧道勘察设计期岩爆灾害预测提供技术支撑。     

Comparison of geoelectrical imaging and tunnel documentation at the Hallandsås Tunnel, Sweden

For construction in rock a thorough pre-investigation is important in order to avoid unforeseen conditions which may delay the work. It is crucial to remember the results from this investigation in the further work, and use the experience from the construction to update the geological prognosis and reduce the uncertainties. Different geophysical methods have proved valuable tools in such investigations. In this work the electrical imaging is evaluated with regards to the method's applicability. The evaluation is done qualitatively by comparing the electrical imaging with tunnel documentation from a tunnel in Southern Sweden. By evaluating the result continuously when making the tunnel a more detailed geological prognosis can be compiled and used in the continued work with the tunnel. The parameters used for the comparison are lithology, Q, RQD, weathering and water leakage. The result was that virtually every change in electrical resistivity image coincides with a change in rock conditions. The general trend was that high resistivity corresponded with good quality gneiss whereas low resistivity corresponds to poor quality rock e.g., high weathering, low RQD, low Q and/or several lithological contacts. The intermediate resistivity is often amphibolites or rock with water bearing fractures. The results were supported by in-situ resistivity measurements inside the tunnel and resistivity logging in a core drilling. Geoelectrical imaging proved to give valuable information for a detailed geological model, which could be compiled for a section where the tunnel had not yet been drilled as a help for planning of the continued tunnel work. As is the case other geophysical methods it is clear that for the interpretation of data a priori information about the geological setting is necessary.     

花梨隧道岩溶水文地质条件及危险性评估

花梨隧道是瓮开高速的控制性工程,其地质构造及岩溶水文地质条件较为复杂。采取现场地质调查、钻探、测量、室内岩土物理力学指标试验、电法物探等综合勘察手段,分析花梨隧道含水层岩性组合特征、可溶岩体系分布特征及岩溶水系统性,查清了其岩溶水文地质条件,并对涌突水危险性进行了分级评价。结果表明:（1）花梨隧道地表出露的可溶岩与非可溶岩,分为泥质粉砂岩组成的非可溶岩与灰岩组成的可溶岩两个体系;（2）花梨隧道预测正常涌水量为32 126.4 m3·d-1,隧道最大涌水量应按预测涌水量的2~6倍考虑;（3）花梨隧道可溶岩段内岩溶涌突水危险性总体为中等危险,其中极高危险段占总长度的16%。      

西南地区某隧道围岩岩爆预测研究

岩爆预测一直是地下工程领域中的世界性难题。本文以西南某隧道工程为例,从岩爆形成的3个条件:岩石岩爆倾向性、岩体完整性和高地应力环境3个方面着手,应用最大储存弹性应变能指标Es和岩石脆性系数B,对深埋隧道区段内可能发生岩爆的石英砂岩、灰岩岩体进行岩爆倾向性分析预测; 基于地应力测量数据资料,采用地质过程动态模拟的有限元分析方法,反演分析隧道工程区岩体地应力场,对隧道高应力区段作出判断; 根据现场所取样品试验结果综合分析隧道围岩的物理力学性质、岩石单轴抗压强度等。在分析和总结前人岩爆预测预报方法的基础上,以工程地质分析为基础,详细阐明隧道岩爆发生的条件,并以岩体力学和非线性科学理论为指导,采用地质综合分析、应力强度比法对隧道可能发生岩爆的部位及其强度进行综合预测。     

TBM在不良地质洞条件下的施工技术

TBM掘进机以其快速、高效、安全、优质等优点越来越广泛地被应用于隧洞开挖施工中,尤其更适用于深埋超长隧洞,然而在不良地质洞段中TBM掘进缓慢,甚至有卡刀可能,反而不如钻爆法灵活,这就需要根据围岩性状采取特殊技术处理措施,辅以监控量测手段对支护方案进行验证、调整支护措施、修正设计参数等。结合辽宁大伙房输水隧洞工程,总结了在不良地质洞条件下的超前地质预报方法、不良地质段处理措施以及围岩变形监测方法。     

TSP探测精度分析及其在过江隧洞超前预报中的应用

针对TSP预报工作耗时长、经验依赖性强等问题,以提高TSP探测精度与效率为目标,分析了影响TSP数据采集与处理精度的关键因素,总结了提高TSP探测效率的经验。结合千岛湖配水工程某过江隧洞段地质超前预报工程,在TSP探测分辨率下降的区域开展TSP跟踪预报或地质雷达探测工作,对物探异常区辅以钻探验证。结果表明:岩体完整性差地段的TSP纵波波速、密度及各力学模量值偏低,TSP对破碎带探测较敏感,对基岩裂隙水识别能力相对较弱,纵、横波波速均偏低的区域岩体富水的概率更大;岩体破碎含水区段雷达电磁异常特征表现为反射波振幅强,同相轴错断,主频偏低。综合预报成果发挥了各种预报方法优势互补的作用,为隧洞支护及超前注浆方案的优化提供了重要参考。      

Engineering geological rock mass classification of Punasa tunnel site,Khandwa District,Madhya Pradesh

Systematic rock mass characterization is an integral part of rock engineering practices. In the present scenario several classifications are in used for rock mass characterization for tunnelling. The present paper discusses engineering geological investigations carried out for Punasa tunnel, a part of Narmada Sagar project. The horse shoe shaped tunnel is 3675.25 m long and 9 m in diameter. This straight and free flow tunnel has been constructed in basaltic lava flows erupted during Cretaceous to Eocene age, belonging to poor to fair rock mass rating (RMR) and extremely poor to good in tunnel quality (Q-system). The values of RMR and Q-system ranges from 29 to 74 and 0.0825 to 13.33 respectively.     

Behaviour of granites and limestones subjected to slow and homogeneous temperature changes

We have studied the evolution of the texture in two granites and two limestones subjected to slow and uniform temperature change. Each granite has a different grain size and each limestone a different texture: Carrare crystalline limestone and Crepey oolitic limestone. Temperature was varied from 200°C to 700°C. Scanning Electron Microscope observations of different rock samples show that during thermal cycling intercrystalline boundaries in granites widen out progressively and porosity increases. New microcracks appear in crystals between 500°C and 600°C. In Carrare crystalline limestone, intercrystalline cracks appear at temperatures as low as 200°C. Due to its heterogeneous cracks appear at temperatures as low as 200°C. Due to its heterogeneous increasing temperature. Longitudinal wave velocity and intrinsic permeability show good correlation with the Scanning Electron Microscope observations.     

挤压和剪切构造环境下深埋隧道岩爆的对比研究

地质构造是影响岩爆的一个重要因素,本文以大瑞铁路高黎贡山深埋隧道为例,在野外地质调查、实测地应力分析、室内岩石力学测试分析的基础上,采用ANSYS软件模拟了在现今构造地应力场中,在褶皱和走滑断层等不同构造部位的岩体中进行隧道开挖所引起的应力重分布特征,对在复杂地质构造地区挤压和剪切构造环境下深埋隧道的岩爆特征进行了深入...     

Drillability prediction: geological influences in hard rock drill and blast tunnelling

 Usually the main subject in preliminary site investigations prior to tunnelling projects is the prediction of tunnel stability. During the past years in conventional drill and blast tunnelling, problems have occurred also connected to the accurate prediction of drillability in hard rock. The drillability is not only decisive for the wear of tools and equipment but is – along with the drilling velocity – a standard factor for the progress of excavation works. The estimation of drillability in predicted rock conditions might bear an extensive risk of costs. Therefore, an improved prediction of drilling velocity and bit wear would be desireable. The drillability of a rock mass is determined by various geological and mechanical parameters. In this report some major correlations of specific rock properties and especially geological factors with measured bit wear and drilling velocity are shown. Drilling velocity is dependent on a lot of geological parameters: Those principal parameters include jointing of rock mass, orientation of schistosity (rock anisotropy), degree of interlocking of microstructures, porosity and quality of cementation of clastic rock, degree of hydrothermal decomposition and weathering of a rock mass. Drilling bit wear increases with the equivalent quartz content. The equivalent quartz content builds the main property for the content of wear-relevant minerals. For various groups of rock types different connections with the equivalent quartz content could be detected. In sandstone bit wear is also dependent on porosity or the quality of the cementation. Finally, an investigation program is submitted, which helps to improve the estimation of rock drillability in planning future tunnel projects. Received: 14 June 1996/Accepted: 10 January 1997     

Rock Mass Characterization and Support Assessment along Power Tunnel of Hydropower in Kohistan Area,KPK, Pakistan

This paper encompasses the engineering geological properties of rock mass along the power tunnel of hydropower in Kohistan, Khayber Pakhtun Khawa (KPK), Pakistan. The major geological units of the study area are Chilas complex (CC) and Gilgit complex (GC) that consists mostly of igneous and metamorphic rocks. Discontinuity surveys were conducted to classify the rock mass by utilizing rock mass rating (RMR) and tunneling quality index (Q) classification systems. RMR system involves collection of data for parameters of rock strength, RQD, spacing of discontinuities, condition of discontinuities, groundwater condition and Q system involves rock quality designation (RQD), joint roughness (J_r), joint sets (J_s), joint alteration (J_a), stress reduction factor (SRF) and joint water reduction (J_w). RMR values ranges from 46 to 66 (fair to good) for rock unit of Chilas complex (CC) and 50 to 58 (fair) for rock unit of Gilgit complex (GC). The evaluated values of tunnel quality by Q-system are 1.55 to 6.4 (poor to fair) for Chilas complex (CC) and 1.35 to 1.84 (poor) for Gilgit complex (GC). The required support along the tunnel route is also estimated by both classification systems. Unwedge program is used to analyze the unstable zones due to the intersection of different joint sets. Total 14 cases are analyzed in Unwedge from which 3 cases have failure potential with FOS less than 1. These failure potential blocks can become stable by applying further support of rock bolting and shotcrete layer.     

Elasto-plastic Behavior of Raghadan Tunnel Based on RMR and Hoek–Brown Classifications

Lining contact pressure and ground deformation of Raghadan transportation tunnel (Amman, Jordan) were investigated. The tunnel is 1.1 km in length and 13.5 m in diameter. This study was intended to integrate useful relations among the widely used rock classification system (RMR: rock mass rating), Hoek–Brown classification, and lining-ground interaction. The materials encountered along the tunnel alignment were limestone, dolomatic limestone, marly limestone, dolomite, and sillicified limestone. The ground conditions along the tunnel alignment including bedding planes, joint sets and joint conditions, rock quality, water flow, and rock strength were evaluated based on the drilled boreholes and rock exposures. Elasto-plastic finite element analyses were conducted to study the effect of rock mass conditions and tunnel face advance on the behavior of lining-ground interaction. The results of the analyses showed that lining contact pressure decreases linearly with the increase in RMR value. Also the results showed that tunnel lining contact pressure and crown inward displacement decreases with the increase in the unsupported distance (distance between tunnel face and the end of the erected lining). Ground displacement above the tunnel crown was found to be increases in an increasing rate with the decrease in the depth above the crown. This displacement was also found to be affected by the RMR value and the unsupported distance.     

基于Hoek-Brown强度准则的隧道软弱围岩稳定性分析

因长期遭受地质作用和构造力的改造作用,地下岩体中存在大量的软弱破碎带,隧道开挖穿越这一地带很容易出现较大的变形,甚至出现塌方等事故。论文采用TGP超前地质预报与掌子面围岩调查相结合的方法进行隧道掌子面及前方未开挖岩体的精细化地质调查,获取了隧道围岩的Hoek-Brown参数。采用FLAC3D数值模拟方法,分析了破碎带围岩在既定支护条件下的稳定性,并与现场监测数据进行对比,验证此方法的正确性。研究结果表明,数值模拟结果与实际监测结果较为吻合,可以将此方法用于指导未开挖段隧道的稳定性预测,以确保隧道掘进过程的施工安全。     

高速铁路隧道围岩抗力系数现场试验与理论研究

以沪昆高速铁路隧道为依托,通过现场径向液压枕试验,测量各级压力下半径向变形,获取了隧道研究点处岩石抗力系数实测值。在实测数据的基础上,结合国内外相关的弹性抗力本构模型,建立了沪昆高速铁路隧道围岩抗力系数的5种理论计算模型：理想弹塑性模型、爆破裂缝弹塑性模型、塑性软化岩体模型、Lade-Duncan准则模型、统一强度理论模型,并有针对性的将所研究的20座隧道进行分类,分别计算其围岩抗力系数理论计算值。为了弥补现场试验点数目的限制,对所研究的隧道展开了数值模拟分析。通过对不同的埋深、围岩级别、地质特征下岩石抗力系数现场试验值、理论计算值、数值模拟值和规范值进行对比和综合,提出了高速铁路大断面隧道的围岩抗力系数推荐值,该推荐值突破了普通铁路隧道规范中关于抗力系数建议值仅限于弹性模型的限制,为优化隧道结构设计,充分利用围岩的自承能力提供了理论依据。     

On steep isogradic surfaces in the Simplon area

The Simplon tunnel (19.7 km long) in the Central Alps crosses, at an altitude of 640–700 m, a mountain chain that culminates in Monte Leone (3 553 m). Along the tunnel axis the metamorphic grade of Mesozoic sediments, recrystallized during the Lepontine phase of the Alpine orogenesis, increases from NW to SE. Investigations on rock samples from the tunnel and from surface exposures give information in three dimensions on conditions during the culmination of Alpine regional metamorphism in the Simplon group. The succession of isograds from km 3 from the NW entrance of the tunnel in SE direction is: First occurrence of biotite, of garnet, last occurrence of albite in paragenesis with calcite, entry of feldspars of the peristerite gap and of oligoclase alone in calc-schists, marbles and amphibolites, coming in of plagioclase An > 30 associated with calcite, first occurrence of staurolite and kyanite, entry of tremolite and calcite, occurrence of plagioclase An >50 in calcschists. Correlation of the data from tunnel and surface samples shows that, in the northwestern and central part of the section, the isogradic surfaces are steeply inclined to the NW, the average dip is 60–75°, with uncertainty between 55 and 90°. In the southeastern part of the section the isogradic surfaces are overturned and dip to the E. No observations indicate gently inclined isogradic surfaces. Geological evidence excludes postmetamorphic tilting of originally subhorizontal isogradic surfaces in such a scale. It is assumed that, during the Lepontine phase, the isobaric surfaces have been subhorizontal, but that the isotherms (which roughly correspond to isograds) have formed angles greater than 45° with isobars. During the culmination of metamorphism vertical and lateral temperature gradients differed considerably from place to place in the Simplon area, and gradually changed also in one and the same direction. The Simplon area is situated near the western edge of the high-grade metamorphic zones of the Ticino complex. The metamorphic conditions described are believed to have been strongly influenced by the eastern adjacent vast thermal bulge of the Central Alps. Thus, not only in Val Bregaglia, with its quite different geological environment, at the E end of the highgrade zone and of the same thermal antiform, but also in the Simplon area in the W, isogradic surfaces are steeply inclined.     

皖北宿州地区寒武系豹皮灰岩地球化学特征及其地质意义

为研究宿州地区寒武系豹皮灰岩地球化学特征及其地质意义,对研究区岩石进行了系统鉴定,并对其主量元素和微量元素进行了地球化学测试。结果显示:寒武系豹皮灰Ti含量、Er/Nd、Y/Ho值均偏低,反应其形成过程中受到陆源碎屑的影响。元素具有明显的U、Pb、Sr、Sm富集及Ba、Nb、Ce、Pr、Zr亏损,稀土总量为3.07×10~(-6)~7.00×10~(-6)(平均为5.33×10~(-6)),低于典型海相灰岩值。V含量较低,V/Cr比值在1.02~1.73之间,说明豹皮灰岩形成于氧化环境;Sr/Ba异常值较高,反映了高度咸化条件下的海相沉积;Sr/Cu值暗示了干旱的气候条件。综合前述认识,研究区豹皮灰岩应形成于局限碳酸盐岩台地环境。     

雪峰山公路隧道的超前预测预报研究

雪峰山隧道为上海－瑞丽国道主干线湖南省邵阳－怀化高速公路上最大的控制性工程,全长约7 km,最大埋深约850 m,为典型的越岭长大公路隧道。采用不同方法,对该隧道的断层破碎带、塌方、岩爆及大变形等地质灾害和围岩稳定性问题进行了超前预测预报研究。研究以地质分析为基础,运用了TSP、地质雷达、赤平投影和关键块体检索法、断层错动机制解、室内岩石力学试验、数值模拟以及隧道内地质观测分析等方法对前方各类地质信息开展超前预报,取得了较好的效果,并成功地预测预报了断层F2的出现及无强烈岩爆灾害的可能性,对安全施工提供了保证,可为今后类似工程借鉴。