Influence of Geological Properties and Operational Parameters on TBM Muck Removal Performance for Yinsong Tunnel

Geotechnical and Geological Engineering - Operational parameters of a Tunnel Boring Machine (TBM) under different geological properties have significant influence on muck removal performance. To...     

综合勘查方法在探测地下断落钻具中的应用

工程钻探中钻具掉落和钻孔偏斜超差一直是孔内事故中发生较多并难以处理的。如果掉落于地下的钻具由于钻孔偏斜超差偏离了设计的地下深度位置,偏斜方位又难以确定,而地下这个深度同时处于地下隧道施工中盾构旋挖设备的行进路线上,钻具有可能斜超差到了盾构施工区域,这样将严重破坏盾构施工设备的正常运行。这种特殊情况要求钻探施工方必须在钻具掉落的深度位置确定遗存钻具偏斜的具体方位,一旦确定钻具偏斜到了地下盾构施工区域内,必须通过各种手段取出掉落钻具。通过工程实例介绍了通过人工开挖探井、管线探测仪、磁力探测仪等多种勘查手段探测地下遗存金属钻具的方法,通过多种方法的应用效果对比,对工程钻探施工中钻杆掉落的工程难题的解决方案进行探讨。     

隧道掘进机施工条件下的隧洞围岩分类方法探讨

针对隧道掘进机(Tunnel Boring Machine--TBM)施工隧洞中的围岩分类问题,指出TBM施工条件下的隧洞围岩分类应针对围岩的可钻掘性,充分考虑影响TBM掘进效率的主要工程地质因素,提出了在《工程岩体分级标准》围岩稳定性基本分级的基础上,依据岩石的单轴抗压强度、岩石的耐磨性和岩体的完整性将TBM施工条件下的隧洞围岩分为A(好)、B(一般)、C(差)3个级别的围岩分类新方法。     

Parameter Study on Prediction Methods for TBM Penetration Rate

Penetration rate prediction of Tunnel Boring Machine (TBM) is the first step to advance prediction process of mechanized tunnelling. In this research, influence of effective parameters on TBM penetration rate is investigated by sensitivity analysis of three main TBM performance prediction methods; Norwegian University of Science and Technology (NTNU), rock mass index (RMi) and Q_TBM. Based on these analyses, it is shown that applied thrust per disc and joint spacing in NTNU and RMi models have more influence on penetration rate. In Q_TBM model, Q value, applied thrust per disc and induced biaxial stress are more effective.     

基于移动阵列电极的盾构超前探测正演响应分析

针对现有超前探测技术探测空间狭小、电磁干扰严重且难以应用于隧道掘进机（Tunnel Boring Machine,简称TBM）施工隧道等难题,采用一种基于移动阵列电极的盾构超前探测方法。运用Comsol Multiphysics有限元仿真软件建立地电模型,对不同地质情况进行正演响应分析。结果表明:存在保护电极时,电压分布范围明显扩大,表明探测范围增大,为提高探测效果,有必要添加保护电极;异常体的尺寸、形状、位置改变会影响测量电压分布呈现规律性变化,表明这种方法对异常反应的响应良好;通过移动阵列电极盾构超前探测物理模型实验结果对比证明了基于移动阵列电极的盾构超前探测方法的可行性。      

A case history of Tunnel Boring Machine jamming in an inter-layer shear zone at the Yellow River Diversion Project in China

This is a case study of a Tunnel Boring Machine (TBM) jamming in a section of the Connection Works No. 7 tunnel of the Yellow River Diversion Project (YRDP) in China. Analysis of tunnel lithology, rock convergence by shearing, rock strength and ground stress, indicates that a high rate of convergence within an inter-layer shear zone in the lower part of an anticline was a dominant factor in the jamming. In addition, the shield encountered unfavorable tunnelling conditions in the form of wet clay, groundwater inflow, and cavities, coincident with tensile stresses in the lower part of an adjacent syncline. Based on these diagnoses, economical and quick measures were adopted, including additional excavation outside of the shield leaving free space to release the TBM. After 9 days of being jammed, the TBM was totally released and resumed normal excavation. This example highlights lessons learned from folding and inter-layer shear zone in TBM tunnelling.     

Development and validation of a 3D numerical model for TBM–EPB mechanised excavations

A 3D numerical model for mechanised excavations is presented, which is capable of simulating the overall process of excavation and construction of a tunnel when a TBM EPB (Tunnel Boring Machine–Earth Pressure Balance) is used.The main construction aspects of a mechanised excavation are modelled. Their influence on calculated ground displacements are investigated by means of a series of parametric analyses.With the aim of testing the performance of the proposed 3D numerical model, a series of 25 Class C predictions has been carried out. Case Histories related to the construction of the 1995–2003 Madrid Metro Extension Project were considered for this purpose.As a general rule, the results obtained with the Modified Cam–Clay model closely fit in situ measurements. When the Linear-Elastic or the Mohr–Coulomb models are used, it is not as easy to summarise the results obtained, as higher fluctuations are observed around in situ measured data. A good agreement is also shown when the distribution of horizontal displacements along depth is considered.For some sections, the mechanised excavation model is not capable of reproducing the high values of the surface settlements measured in situ. A closer look at the results shows that mixed face conditions are found for these cases, with the TBM excavating through layered soil formations having sharply different mechanical behaviour.     

TBM施工岩巷掘探一体化技术研究进展与思考

煤矿岩巷全断面掘进机(TBM)施工,是满足集约化、现代化、智能化大型矿井深部高强度开发采掘平衡与高效建设生产的重要方法之一。但是,TBM掘进对于不良地质条件适应性较差,尤其是破碎带、断层、软弱岩层及富水区等复杂地质条件会造成坍塌、卡机、卡盾、涌水等问题,从而限制了其发展。为充分发挥TBM快速掘进效率,将超前探测仪器与TBM机械进行一体化设计,开展随掘探测是煤矿岩巷TBM掘进发展亟需突破的关键技术。从TBM施工岩巷的掘探一体化技术研究出发,回顾了近年来隧道、煤矿岩巷随掘探测技术新进展,介绍了包括随掘地震、随掘电法、随掘瞬变电磁等掘探一体化技术;围绕提高随掘超前探测精度,实现高精度异常体成像,论述了岩巷TBM掘探一体化技术的发展方向,包括超前探测数据采集系统、信号处理方法、巷道界面成像新方法新技术等。认为掘探一体化设备要向自动化、信息化、智能化方向发展,要形成以智能化控制系统为核心的掘进、探测、预报集成化管理平台,实现掘进参数的智能选取、超前探测数据的实时处理与叠加成像,形成掘探一体智能控制与地质条件融合判识系统,为深部煤炭资源的精准开发利用与煤矿智能化建设提供透明地质条件支撑。      

煤矿井下随掘地震震源特征及探测性能研究

煤矿智能化背景下,随掘地震已经成为掘进工作面安全掘进的地质保障关键技术之一,可实时、超前、精细探明掘进前方的隐蔽地质构造,如采空区、断层、陷落柱等,有效促进掘进生产安全高效。不同于广泛采用的反射槽波超前探测技术,随掘地震采用了掘进机掘进时震动信号作为激发源,替代了常规地震勘探中的炸药震源,具有震源绿色、安全、成本低、可重复、探掘同步等优点。由于掘进机震源在激发方式、能量、频率、带宽等方面与炸药震源差别较大,因此其探测性能受到很多关注。从随掘地震的震源机制、波场特征、传播距离、成像准确率等方面进行研究,详细分析其探测性能,认为随掘地震波场中槽波和横波发育,可利用槽波或横波进行超前探测;Y分量具有更好的信噪比优势,但在实际应用时考虑到反射面的走向,相同设备量情况下,Z分量更有优势;随掘地震的直达横波传播距离可达700 m以上,横波超前探测距离可达到300 m以上;随掘地震的直达槽波传播距离可达400 m 以上,槽波超前探测距离可达到170 m以上;常规掘进速度下,反射波叠加次数可达到16次,相比常规的一次探测,信噪比可提升4倍,有效提高了探测精度和准确度。后续将通过大量的随掘应用数据进一步修正随掘地震技术的性能参数。      

From plate tectonics to the design of the Dul Hasti hydroelectric project in Kashmir (India)

The Dul Hasti hydroelectric scheme, which consists of a 65-m high gravity dam, a 10.6-kin long headrace tunnel and an underground powerhouse, is being built on the Chenab River, a tributary of the Indus River, within the Himalayan Range of Kashmir, India. This paper shows how the geological knowledge at the time of signature of the contracts between the National Hydroelectric Power Corporation and a French consortium in September 1989 was radically modified through successive on-site investigations, geological field surveys and seismotectonic analyses carried out at various scales. The actual geological, tectonic, geotechnical and hydrogeological conditions discovered in the last three years (active faulting, deep infilled graben, sheath folds, general mylonitisation of the rockmass, confined aquifers with very high heads of water, widespread opening along joints filled with silty material highly susceptible to untamping and piping under even low heads of water) have led the designer to modify the tunnel layout, the tunnel design, and the construction methods. In particular, the assessment of tunnelling conditions requires modifying the Tunnel Boring Machine and installing additional equipment for frequent advance investigations ahead of the tunnel face,and special treatments of zones of low mechanical properties. An identified joint filled with silty material under a high head of water will be crosscut by (a) drilling a complete ring of pressure relief holes crossing the jointaround the tunnel, (b) a special grouting treatment under very high pressure including cement grouts and silica gels or in some cases resins, and (c) increasing the final lining of the tunnel using a high strength concrete to bear the full ground-water pressure. On crossing rock formations with reduced mechanical properties, (a) long and numerous rock bolts(or full-length adhesive anchors) will have to be implemented near the tunnel head to prevent further softening of the rock during radial plastic deformation and (b) the external diameter of the tunnel will have to be increased to maintain the final internal diameter and the minimum foreseen concrete lining thickness. The sequence of investigations performed since 1960 highlights the fact that the acquisition of such an extremely complex geological and tectonic database is a long, difficult and ongoing process. Moreover, it shows that a reliable estimation of geological tunnelling conditions (geology, hydrogeology, old and active tectonics and geotechnics) depends on an understanding of the present and past geodynamics of a given region at different scales: from plate tectonics to fault scarps and microtectonics.     

Environmental effects of tunnel excavation in soft and shallow ground with EPBM: the case of Istanbul

In metro tunnel excavations, it is important to control surface settlements observed before and after excavation, which may cause damage to surface structures. Otherwise, the metro tunnel cannot perform the task expected, and the advantages of the tunnel are lost. In this study, short-term surface settlements and their effect on buildings are examined in three zones for twin tunnels, which have been excavated between the Otogar and Kirazlı 1 stations of the Istanbul Metro line, and are 5.8 km in length. Geology in the study area is composed of fill, stiff clay, dense sand, very dense sand, and hard clay, respectively, starting from the surface. Tunnels are excavated by using two Earth Pressure Balance Tunnel Boring Machines (EPBMs) with a 6.5 m diameter as twin tubes with 14 m distance from center to center. The EPBM in the right tube is followed about 100 m behind the other tube. Segmental lining with 1.4 m of length is currently employed as final support. The results of this study indicate that, with EPBM excavation method in shallow depths and soft grounds, the damage done to the environment prolonged project costs up to 15.8% more. In addition, tunnel conditions prolonged the project schedule to 29.3%.     

Investigating the Economic Performance of Tunnel Excavation in Iran: 1998–2013

Nowadays, the world is witnessing the ever increasing need of Tunnel excavation due to their unique features and the kind of human applied plans. This has led to increase in demand of excavating this engineering factor. Tunnel excavation process faces a lot of challenges due to environmental and technological complexities which causes the economic evaluation and investigation of this project to be difficult. It is tried to develop the proposed model with regard to efficiency concept in order to evaluate and investigate the efficiency of relative economic performance of Tunnel excavation projects and turn to its modeling and implementing by data envelopment analysis and Fuzzy DEMATEL techniques. The results in Iran showed that the proposed model can turn to investigation and evaluation of economic efficiency of Tunnel excavation by considering two optimistic (ideal) and pessimistic perspectives such that the Tunnel excavation process of “Karaj water transition” and “Cheshmelangan water transition” among 12 rock Tunnel excavation projects of Iran in the time period of 1998–2013 were respectively introduced as the most efficient and the most inefficient rock Tunnel excavation projects.     

导向钻进非开挖技术在地下管线铺设中的应用

结合邯郸市集中供热管道工程实例,说明导向钻进非开挖在铺设地下管线施工中的成功应用,对导向钻进非开挖技术、导向孔轨迹设计、施工质量控制及施工效果等作了介绍与总结,为同类工程实践提供参考。     

渝遂高速公路中梁山隧道岩溶塌陷及涌水量分析

修建于20世纪70年代的襄渝铁路中梁山隧道对测区水文地质环境影响很大。本文紧扣渝遂高速公路中梁山隧道横穿中梁山背斜且紧临襄渝铁路中梁山隧道这2大主题,详细分析隧道水文地质条件,预测了其涌水量和可能产生的岩溶塌陷。     

Geochemical controls on ground water composition at the Cripple Creek Mining District,Cripple Creek,Colorado

A combined approach involving evaluations of historical information, compositional trends, site mineralogy, and forward and inverse geochemical modeling was used to assess the effects of Au mining on ground water quality at the Cripple Creek Mining District. The District is located in a Tertiary volcanic diatreme complex surrounded by Precambrian granite. Historically, mining activity was underground whereas present-day mining occurs in surface mines. Between 1896 and 1941, a series of tunnels was excavated to drain the underground mining areas. The Carlton Tunnel, located about 900–950 m below the surface, is the primary ground water drain for the mining areas. Ground water flowing from the Carlton Tunnel has historically been of good quality. The geochemical processes controlling the quality of the Carlton Tunnel water were the focus of this study. Mineralogical and acid/base accounting data indicate that the diatreme is zoned vertically from an oxidized condition with acidic paste-pH, acidic ground water, and elevated metal concentrations near the surface to an alkaline condition with high pH, elevated SO₄, and low metal concentrations at depth. The average travel time of water from the surface to the Carlton Tunnel is estimated to be at least 25a based on ³H determinations. Forward geochemical modeling results indicate that this travel time is sufficient for ground water to reach equilibrium with calcite, gypsum, and fluorite by the time it exits through the Carlton Tunnel. Equilibrium processes have effectively fixed the pH, alkalinity, and SO₄ in the Carlton Tunnel water to near-constant levels for at least 24–70a based on comparisons to historically reported water compositions. Inverse geochemical modeling results indicate that there is sufficient neutralization capacity at depth in the diatreme to maintain the current good quality of the ground water flowing from the Carlton Tunnel for the forseeable future, assuming no significant changes in hydrogeochemical conditions.     

复杂地层水下盾构隧道工程难点及关键技术研究与展望

国家经济一体化需求推动了城市交通网络的蓬勃发展,众多水下盾构隧道工程应运而生。特别是进入21世纪以来,一系列长距离越江跨海隧道的建成和投运标志着我国水下盾构施工成套关键技术取得了显著进步。为促进复杂困难地层盾构掘进技术发展,推动越江跨海隧道施工效率提升,本文以近年来已建和在建的代表性大型水下隧道工程为研究对象,从隧道地质环境、盾构施工技术、工程项目管理等多个角度出发,概述了南京长江隧道、济南黄河隧道、南京地铁10号线越江隧道、苏通GIL综合管廊工程、厦门地铁2号线海底隧道等长距离高水压盾构隧道的工程问题和技术难点,梳理了高磨蚀性砂卵石地层、高黏粒粉质黏土地层、高水压强渗透性地层、江底富含沼气地层、海域密集孤石群地层等复杂地质条件下的水下隧道施工成套关键技术,分析了越江跨海隧道工程地质环境复杂化、盾构设备多样化、掘进施工智能化的未来发展趋势。相关研究成果可为后续复杂地质条件下水下盾构隧道工程的勘察、设计、施工等提供理论依据和技术支撑。     

带裂纹隧道二次支护内设衬套补强效果的有限元分析

以平面有限元位移法对铁山隧道和大垭口隧道带裂纹二次支护内设钢筋混凝土衬套的补强效果进行了数值模拟。模拟结果表明：加了钢筋混凝土衬套后,可大大降低裂纹尖端的应力强度因子,显著地提高衬砌承载安全系数。     

综合超前地质预报方法在宜万铁路云雾山隧道施工中的应用

云雾山隧道是宜万铁路的重要控制性工程之一,针对该隧道的工程地质和水文地质条件,采取了综合超前地质预报方法,降低了隧道施工风险,加速了工程进度和保证了工程质量,对以后相似隧道的施工提供借鉴意义。     

Endolithic biodegradation of cool-water skeletal carbonates on Scott shelf, northwestern Vancouver Island, Canada

Biodegradation of shell material is widespread in the cool-water skeletal carbonate deposits on Scott shelf, northwestern Vancouver Island, and is especially evident in the large aragonitic bivalves, Glycymeris and Humilaria, major primary sediment contributors. Ten types of endolithic microborings have been identified in the shells, including representatives of green algae (e.g., Ostreobium quekettii), blue-green algae (e.g., Plectonema terebrans, ?Scytonema sp.), fungi, bacteria and clionid sponges, as well as macroborings of phoronids, polychaetes and naticid gatropods. Microcrystalline carbonate is not precipitated in vacated bores. Boring physically weakens the shells, rendering them more prone to mechanical abrasion during sediment transport and bioturbation, and to biological abrasion by grazing benthos. Tumbling experiments demonstrate that the rate of carbonate mud production is much greater for bored as compared to fresh bivalve shells, and that mud production rates decrease with tumbling time because most endolithic microborings are confined to the periphery of grains. Boring also increases significantly the porosity and surface area of skeletal grains, and destroys their organic matrix, making them susceptible to maceration and dissolution on cool-water shelves. Fostered by the generally low rates of carbonate production and accumulation, many aragonitic bivalve shells on Scott shelf have become thoroughly degraded through a combination of endolithic microboring, maceration and dissolution within about 1000 years in ambient sea water. In geologic terms, such selective taphonomic loss of skeletal material may be considerable in ancient temperate-shelf limestones and should be evaluated when interpreting their paleoecology and paleoenvironments.     

凌子口隧道围岩稳定性分析评价

根据勘察资料对位于云南省昭通市北东约30km处凌子口隧道围岩的稳定性进行分析评价。隧道所处区域为滇东北拗褶带中心峡谷区，工程地质条件复杂，岩层分别为砂岩、白云岩、泥灰岩及钙质泥岩，岩体结构面主要为构造结构面，不良物理地质现象主要为进洞口附近残坡积层中发育的三个小滑坡。对隧道围岩计算得出各类岩体强度应力比均大于6，该隧道围岩能够承受围岩应力的作用，不会产生过大的整体塑性变形，剪切及弯折等变形破坏。但围岩中分离块体存在散块状松动坍塌的可能。本文根据分类评价结论及有关参数，提出了一次支护型式建议。