建立隧道掘进机产业促进我国地下空间开发

论述了国际地下工程建设动态，指出在地下工程建设中，优先采用全断面隧道掘进机（TBM）进行快速开挖已成料总的发展趋势；对我国开发隧道掘进机的历史和现状进行了综述，提出了存在的问题有利条件，对在我国建立隧道掘进机产业提出了意见和建议。     

基于临界稳定断面的隧道围岩稳定性分析方法探讨

为定量评价隧道围岩的稳定性并指导支护设计,提出了隧道临界稳定断面的概念及基于临界稳定断面的隧道围岩稳定性分析方法,主要包括以下内容：（1）提出了隧道临界稳定断面的概念,即与设计开挖断面中心埋深相同、几何形状相似在无支护状态下围岩能够自稳的最大断面;（2）当设计开挖断面小于临界稳定断面时,临界稳定断面与设计开挖断面之间的围岩可以作为支护结构利用,且当其安全系数满足设计要求时,认为围岩能够长期自稳,除进行局部防护外,不需要系统支护,否者需要补充工程支护措施;（3）当设计开挖断面大于临界稳定断面时,需要工程支护;（4）当需要工程支护时,提出了设计支护力的计算方法,即认为破坏区范围内的围岩为松散体,设计支护力P_(i)应能维持该松散体的稳定且具有一定的安全系数。通过该方法,对两种典型断面形式的铁路隧道的临界稳定断面进行了研究,并计算了不同围岩级别、不同埋深条件下围岩的自承载安全系数与所需的工程支护力。本文可以为隧道围岩稳定性的量化分析、支护设计等提供一种新的思路。     

城市地下软弱围岩超大断面隧道施工工法

如何保障超大断面隧道的稳定性是当前国内外地下工程亟需解决的技术难题,而超大断面隧道在穿过软弱围岩地带时更容易发生变形失稳破坏等现象.选择合理的开挖工法对隧道施工时的安全性以及围岩的支护控制效果都具有重要意义.以深圳侨城东路北延通道工程东路隧道标准段为研究背景,针对超大断面隧道、地质条件复杂、围岩多为Ⅳ至Ⅴ级的复杂特征,通过原位钻探和室内岩石物理力学实验,获得隧道围岩关键参数,分析隧道围岩大变形机理;利用FLAC3 D数值模拟软件建立隧道模型,模拟全断面法、CRD法、三台阶法和三台阶七步预留核心土法4种不同开挖工法对隧道软弱围岩稳定性的影响;通过揭示其位移应力变化规律,结合室内相似比物理模型试验结果,总结大跨度隧道围岩的应变特征.研究表明:三台阶七步开挖法为侨城东路隧道标准段的最优开挖工法.     

基于临界稳定断面的隧道围岩稳定性分析方法探讨

为定量评价隧道围岩的稳定性并指导支护设计,提出了隧道临界稳定断面的概念及基于临界稳定断面的隧道围岩稳定性分析方法,主要包括以下内容：（1）隧道临界稳定断面就是与设计开挖断面中心埋深相同、几何形状相似在无支护状态下围岩能够自稳的最大断面;（2）当设计开挖断面小于临界稳定断面时,临界稳定断面与设计开挖断面之间的围岩可以作为支护结构利用,且当其安全系数满足设计要求时,认为围岩能够长期自稳,除进行局部防护外,不需要系统支护,否则需要补充工程支护措施;（3）当设计开挖断面大于临界稳定断面时,需要进行工程支护;（4）提出了设计支护力的计算方法,即认为破坏区范围内的围岩为松散体,设计支护力 应能维持该松散体的稳定且具有一定的安全系数。通过该方法,对两种典型断面形式的铁路隧道的临界稳定断面进行了研究,并计算了不同围岩级别、不同埋深条件下围岩的自承载安全系数与所需的工程支护力。研究成果可以为隧道围岩稳定性的量化分析、支护设计等提供一种新的思路。     

武汉地铁隧道开挖引起地表沉降的数值模拟研究

城市地铁隧道开挖引起过大的地表沉降会对隧道工程本身及地表建筑物造成危害。有效预计并合理控制隧道开挖引起的地表沉降具有重要的实践意义。以武汉地铁虎名区间隧道开挖工程为背景,运用有限元数值模拟软件MIDAS/GTS建立隧道断面开挖的数值模型,计算隧道开挖引起的地表沉降量,与实测沉降量进行拟合; 根据隧道开挖过程中对应地表及临近建筑物的实际情况,优化开挖断面围岩预处理方案,建立优化后的断面开挖模型。模拟结果表明,优化后地表沉降仍在安全范围内,可以为类似工程沉降控制提供参考。     

典型隧道断面形态对拟建滇西大理至瑞丽铁路 高黎贡山隧道稳定性影响的数值模拟分析

拟建的大理—瑞丽铁路穿越横断山区南段的滇西南地区,地形、地貌和地质条件都极为复杂,其中高黎贡山深埋超长隧道的工程稳定性问题一直是困扰铁路选线、设计和施工的重大工程难点。针对不同形态隧道断面可能对高黎贡山超长隧道工程稳定性产生的影响问题,在充分综合该区野外地质调查、地应力测量、岩石力学实验等成果与资料的基础上,利用ANSYS有限元应力分析软件对不同形态隧道断面的应力分布进行了有限元计算,给出了应力分布图像,分析了断面应力分布的特点和断面形状对应力分布的影响。同时,计算了围岩的应力与强度比,对2种不同断面的围岩稳定性进行了分析对比,最后根据分析结果对不同隧道断面形态下的隧道稳定性进行了综合评价,并据此提出了铁路隧道断面设计与施工中应重点关注的问题。     

典型隧道断面形态对拟建滇西大理至瑞丽铁路高黎贡山隧道稳定性影响的数值模拟分析

拟建的大理—瑞丽铁路穿越横断山区南段的滇西南地区,地形、地貌和地质条件都极为复杂,其中高黎贡山深埋超长隧道的工程稳定性问题一直是困扰铁路选线、设计和施工的重大工程难点。针对不同形态隧道断面可能对高黎贡山超长隧道工程稳定性产生的影响问题,在充分综合该区野外地质调查、地应力测量、岩石力学实验等成果与资料的基础上,利用ANSYS有限元应力分析软件对不同形态隧道断面的应力分布进行了有限元计算,给出了应力分布图像,分析了断面应力分布的特点和断面形状对应力分布的影响。同时,计算了围岩的应力与强度比,对2种不同断面的围岩稳定性进行了分析对比,最后根据分析结果对不同隧道断面形态下的隧道稳定性进行了综合评价,并据此提出了铁路隧道断面设计与施工中应重点关注的问题。     

万家寨引黄工程泥灰岩段隧洞岩石掘进机(TBM)卡机事故工程地质分析和事故处理

隧道全断面岩石掘进机 (TBM )的施工对地质条件适应性是一个不断认识和深化的过程 ,其中很多认识是来自已发生的各种各样事故和对事故原因的理性认识。本文是在对某隧洞TBM卡机地段的岩性 (包括工程性质 )、构造、地应力及其在TBM施工条件下的变化等方面进行工程地质力学研究的基础上 ,指出层间剪切带的存在及由此而产生的较大变形速率是导致事故发生的工程地质原因 ,并提出了相应的处理意见和建议。TBM卡机问题的顺利解决和它重新开始快速掘进证明了作者分析和工程处理措施的合理性。本文的分析有助于加深TBM施工对复杂地质条件适应性的认识 ,并可望为避免类似事故的再次发生提供参考和借鉴。     

采用矿山法构筑区间盾构隧道渡线段的方案探讨

针对北京地区地质条件,提出了在区间盾构隧道之间采用矿山法构筑渡线隧道的方案,即先在最大开挖断面处拆除管片,沿横向扩挖出一条施工通道;然后在施工横通道侧壁开口,从大断面向小断面进行渡线隧道的断面渐变段、双联拱段和分离单洞的施工,从而在两条区间盾构隧道之间采用矿山法完成渡线隧道的施工;最后,应用FLAC数值计算软件,探讨了管片拆除及隧道断面扩挖引起的地表沉降和塑性区分布范围。研究结果表明,针对北京地区的地质条件,提出的在区间盾构隧道之间采用矿山法构筑渡线隧道的方案具有工程适用性。     

隧道施工期超前地质预报实施方法研究

地质信息采集、超前预报与数据解译是隧道超前地质预报中的3个重要环节,首先讨论了超前开挖隧道的地质编录的工作方法,包括风险靶段分级、掌子面地质素描,进而绘制平面地质图,建立三维地质模型,计算不良地质体及含水体在相邻未开挖隧道的出露位置。在此基础上,详细讨论了仪器配合的关键问题,并开发了隧道超前地质预报自动选择程序,可以帮助操作员从中选择不同岩性地区、不同构造发育特点、不同地下水文条件下需要选择的预报方法,并建议了特殊地段的预报方法选择,最后结合工程实例讨论了几种常用的预报方法的数据解译过程中应注意的问题及典型不良地质体的判据。其结果对于隧道超前地质预报工作具有一定的借鉴与指导意义     

软土地层TBM开挖面支护压力计算模型及可视化

隧道掘进机（TBM）近年来在世界范围内得到了广泛应用,通常通过完全充满压力仓的泥土或泥浆来支护开挖面。但在较差的地层和水力条件下,开挖面失稳时有发生。事实上,TBM开挖面的支护压力的大小直接决定了施工安全及地表变形。基于所建立的开挖面支护压力计算模型,并考虑复合地层下土体分层带来的影响,通过计算机编程方法,建立了界面友好、使用便捷的开挖面支护压力可视化计算平台(TBM Studio);并结合阿拉斯加隧道、钱江隧道工程实例进行了不同模型结果的验证分析,给出了各模型计算结果的差异性;讨论了软土复合地层条件下,土体自稳性对开挖面稳定的影响,认为软土地层中定量确定有效支护压力和水头高度至关重要,研究为正确评价TBM开挖面稳定性提供了相应的计算模型。     

Estimation of the performance of the tunnel boring machine (TBM) using uniaxial compressive strength and rock mass rating classification (RMR)–A case study from the Deccan traps,India

The competency of any TBM in any geological condition is determined by a rock or rock mass breakage process. A 12.24 km long tunnel between Maroshi and Ruparel College was excavated by Brihanmumbai municipal corporation (BMC) to improve water supply system of greater Mumbai, India, using open-type hard rock tunnel boring machines (TBMs). In this paper an attempt has been made to establish the relationship between rock mass characteristics i.e. RMR and UCS of the Deccan trap rocks and TBMs performance characteristics for 5.83 km long Maroshi–Vakola tunnel section of the Maroshi–Ruparel college tunnel project. To analyze the effect of variable rock mass conditions on the TBM performance, the operating parameters i.e. thrust force, torque and RPM of the machine, were recorded and intact rock strength was determined. The effect of rock mass properties on machine penetration rate (PR) and the relation with other operational parameters were analyzed. The rock strength affects the rock behaviour under compression. When the rolling cutters indent the rock, the stress exerted must be higher than the rock strength i.e.; the rock strength is directly relevant to the performance of TBM. Studies show that the penetration rate decreases with increase in uniaxial compressive strength (UCS). The comparison of measured penetration rate with empirical model developed by Graham, in which, the penetration rate is computed using UCS and average thrust per cutter, showed good agreement with coefficient of determination (R²), i.e. 0.97. The study shows that the TBM performance was maximum in rock mass rating (RMR) range from 40 to 75, while slower penetration was recorded both in very poor and very good rock masses.     

A Completely 3D Model for the Simulation of Mechanized Tunnel Excavation

For long deep tunnels as currently under construction through the Alps, mechanized excavation using tunnel boring machines (TBMs) contributes significantly to savings in construction time and costs. Questions are, however, posed due to the severe ground conditions which are in cases anticipated or encountered along the main tunnel alignment. A major geological hazard is the squeezing of weak rocks, but also brittle failure can represent a significant problem. For the design of mechanized tunnelling in such conditions, the complex interaction between the rock mass, the tunnel machine, its system components, and the tunnel support need to be analysed in detail and this can be carried out by three-dimensional (3D) models including all these components. However, the state-of-the-art shows that very few fully 3D models for mechanical deep tunnel excavation in rock have been developed so far. A completely three-dimensional simulator of mechanised tunnel excavation is presented in this paper. The TBM of reference is a technologically advanced double shield TBM designed to cope with both conditions. Design analyses with reference to spalling hazard along the Brenner and squeezing along the Lyon–Turin Base Tunnel are discussed.     

Some Attempts for Estimating Rock Strength and Rock Mass Classification from Cutting Force and Investigation of Optimum Operation of Tunnel Boring Machines

Summary. Tunnel face and wall collapse are common during excavations performed by tunnel boring machines (TBMs) due to the difficulty of correctly identifying the properties of the excavated rock. This identification, however, can be simplified by using the cutting force to estimate rock strength, a method that has already proved quite successful in Japanese tunnel excavations. This paper summarizes knowledge relating to the cutting force obtained through tunnel excavation experience, and the relationship between rock strength and TBM operation is discussed. Although TBM operators rely on intuition to set the cutter head speed appropriately, this decision process represents a logical method of operation that takes advantage of the variable speed capability of the cutter head. Selection of appropriate support methods for the excavated face is also a critical issue in tunnel excavation. This selection process is based on the condition of the rock, which is difficult to determine quickly and accurately during tunnel excavation. The present paper uses the excavation of two tunnels to demonstrate that it is possible to assign rock mass classifications accurately based on rock strength when boring a uniform rock type. It is also shown that the rock mass can be classified from the rock strength normalized by the uniaxial compressive strength when boring through mixed rock types.     

Developing new equations for TBM performance prediction in carbonate-argillaceous rocks: a case history of Nowsood water conveyance tunnel

Nowsood water conveyance tunnel is 49 km long and has been designed for transferring 70 m³/s water from Sirvan river southward to Dashte Zahab plain in the west of Iran. This long tunnel has been divided into three sections, namely 1A, 1B and 2. By April 2008, about 5.3 km of the lot 2 of this project, with a total length of 26 km, were excavated by a double-shield TBM. The bored section of tunnel passed through different geological units of three main formations of the Zagross mountain ranges which mainly consist of weak to moderately strong argillaceous-carbonate rocks. This paper will offer an overview of the project, concentrating on the TBM operation, and review the results of the field performance of the machine. Also results of statistical analyses to evaluate correlation of TBM performance parameters with rock mass characteristics will be discussed. The results of machine performance analysis indicated that there are strong relationships between geomechanical parameters and TBM performance parameters in this particular project. In this research some empirical equations and a chart have been developed to estimate TBM performance parameters in similar cases based on common rock mass properties.     

A comparative study of different machine learning algorithms in predicting EPB shield behaviour: a case study at the Xi’an metro,China

Acta Geotechnica - Complex geological conditions and/or inappropriate shield tunnel boring machine (TBM) operation can significantly degrade both the excavation and safety of tunnel construction....     

TBM Performance Analysis in Pyroclastic Rocks: A Case History of Karaj Water Conveyance Tunnel

Karaj Water Conveyance Tunnel (KWCT) is 30-km long and has been designed for transferring 16 m³/s of water from Amir-Kabir dam to northwest of Tehran. Lot No. 1 of this long tunnel, with a length of 16 km, is under construction with a double shield TBM and currently about 8.7 km of the tunnel has been excavated/lined. This paper will offer an overview of the project, concentrating on the TBM operation and will review the results of field performance of the machine. In addition to analysis of the available data including geological and geotechnical information and machine operational parameters, actual penetration and advance rates will be compared to the estimated machine performance using prediction models, such as CSM, NTNU and Q_TBM. Also, results of analysis to correlate TBM performance parameters to rock mass characteristics will be discussed. This involves statistical analysis of the available data to develop new empirical methods. The preliminary results of this study revealed that the available prediction models need some corrections or modifications to produce a more accurate prediction in geological conditions of this particular project.     

Rock burst and slabbing failure and its influence on TBM excavation at headrace tunnels in Jinping II hydropower station

Two headrace tunnels and the drainage tunnel were excavated by tunnel boring machines (TBMs) in Jinping II Hydropower Station. During TBM excavation, two types of slabbing failure were encountered in these deep buried marble tunnels. One is rock bursting and the other is non-violent slabbing. In order to study the rock burst and slabbing failure, a unique true triaxial rock burst test was carried out to simulate the rock burst process with different in situ stresses. Four rock samples in different marble layers were obtained in the site, and then four experiments are conducted under the same stressed conditions as the in situ field. The rock burst process and slabbing failure phenomena of the four experiments are in good accordance with the observations of corresponding excavation site. The failure modes of slabbing and rock burst in different rock groups can be predicted based on the experiments. The influence of the slabbing and rock burst failure on TBM excavation is analyzed in depth. Non-violent slabbing is beneficial to the rock breakage process. Rock burst with violent slabbing process greatly affects the tunnel support, cutter and cutterhead damage, gripper movement and force and so on.     

开敞式TBM过类泥石流不良地质洞段施工处理技术

开敞式TBM在掘进过程中,往往会遇到断层破碎带,目前业界已经有相应的处理方式,但是在遇到类泥石流洞段时,单独依靠目前TBM自身条件及已有的处理方式很难实现顺利通过,需要采取特殊的施工处理措施相互配合才能通过。本文依托吉林引松供水项目三标段类泥石流不良地质洞段的处理,形成了一套完整的开敞式TBM过类泥石流不良地质洞段施工处理技术,即在碎块石夹杂断层泥段采用超前管棚支护,在类泥石流不良地质洞段采用堵水灌浆加固技术并配以喷锚喷网 钢拱 模筑混凝土的联合支护技术。工程实践验证了该技术的可行性。     

双护盾TBM施工隧洞综合超前地质预报方法研究

由于受护盾、管片及电磁干扰的影响,地质素描、炸药激振地震法、电磁法等超前地质预报方法在双护盾TBM施工中无法使用。根据双护盾TBM技术特点,以CCS水电站引水隧洞为工程背景,提出了以地质分析法、物探法、和超前钻探等为主的综合超前地质预报方法。综合超前地质预报采用"由粗到细、点面结合"的原则。地质分析法包括隧洞沿线地质分析、施工地质观察、岩渣及掘进参数分析等,不占用TBM掘进时间,成本低,可全洞段采用。物探法包括ISIS地震法和BEAM电法。物探法和超前钻探占用TBM掘进时间,且预报成本较高。因此,应根据预报精度、预报成本及是否占用掘进时间综合权衡后,确定采用何种预报方法。基于综合超前地质预报结果,针对不良地质条件,提出了相应的处理措施。研究结果表明,综合超前地质方法符合双护盾TBM施工特点,能有效识别掌子面前方的不良地质条件,同时可为工程应对措施提供基础支撑,从而有效避免或降低不良地质条件的影响。