浅析TBM隧道围岩的工程分类

结合影响TBM施工效率的各种主要因素,提出了关于TBM隧道围岩分级的一些看法,认为TBM施工条件下的隧道围岩分级应该主要针对工程岩体的可掘进性,即根据围岩的主要地质因素与TBM工作效率的关系来划分。     

深部高应力隧道TBM护盾长度和推力计算方法研究

岩石隧道掘进机(TBM)法开挖长隧道是一种安全、快速、有效的隧道开挖方法,但TBM复杂高应力隧道掘进时易发生卡机事故,因此,TBM在设计之初应尽可能考虑地质环境的影响,降低TBM的卡机风险。通过分析高应力常规地层和高应力软弱破碎地层对TBM的影响,提出了高应力常规地层和高应力软弱破碎地层TBM卡机的两个判据。根据两个判据提出了考虑围岩力学参数的高应力隧道TBM护盾长度设计和推力设计理论计算方法,并给出了参数选取依据。最后依据西南地区某高应力隧道的实际围岩地质参数,计算分析了现有TBM设计的合理性。本研究可为TBM的盾体长度和推力设计计算提供围岩力学参数依据。     

TBM自重对围岩变形影响的数值模拟研究

为研究双护盾全断面隧道掘进机(TBM)自重对围岩变形的影响,基于FLAC3D有限差分软件,通过改变隧道的埋深与围岩条件,建立3种工况数值模型,并对每个工况分别进行了考虑TBM自重与不考虑其自重的数值模拟,以对比各种工况下有无TBM自重作用的隧道围岩纵向位移曲线(LDP曲线);研究了TBM自重对围岩变形的影响。模拟结果表明,TBM自重可抑制隧道围岩的径向位移,并随着开挖隧道的围岩等级升高、埋深变浅,其自重对围岩变形的影响越大,且与不考虑TBM自重的围岩变形相比,边墙洞壁的径向位移减小率最大,仰拱与拱顶次之。这些认识对研究TBM与围岩的相互作用和预测卡机有重要意义。     

浅埋暗挖重叠隧道施工引起的地层变形分析

 重叠隧道施工必然发生相互影响,产生诸如地表沉降难于控制等一系列问题,特别是在浅埋富水软弱围岩条件下修建重叠隧道,此类问题更加明显。通过对深圳地铁一期工程国贸～老街区间重叠隧道施工引起的地层变形实测分析,得出了富水软弱围岩条件下浅埋暗挖重叠隧道施工引起的地层运动规律。在该类地层条件下施工重叠隧道,具有变形量大、地表沉陷突发、地层损失率高(地层损失率高达9.2%,远大于一般地层)、地表横向沉降槽局部曲率和斜率大的显著特征。结合隧道围岩性质试验成果和现场工程条件,对地层变形机制及其主要影响因素进行分析,在此基础上提出该类围岩条件下施工浅埋暗挖重叠隧道控制地层变形的技术措施,并在深圳地铁I期工程的后期施工中得到充分利用,取得了显著效果。研究成果对同类地层暗挖重叠隧道施工地层变形控制具有借鉴和参考价值。     

高地应力区双护盾TBM隧道围岩性态即时判示分析

青藏高原及其东缘高山区的交通建设和能源开发,需要修建众多的深埋长大隧道,采用TBM掘进具有显著优势.依托西藏雅鲁藏布大峡谷DXL隧道双护盾TBM掘进施工,就隧址区工程地质环境、基于尾渣的围岩特征信息的即时获取方法以及围岩性态判别等进行了研究.结果表明:(1)高地应力环境下,隧址区裂隙性硬质围岩微细观破裂,造成宏观大变形...     

挤压性围岩隧道大变形机理及分级标准研究

结合高地应力条件下挤压性大变形隧道--乌鞘岭隧道工程实例,通过变形的现场量测结果,分析了挤压性围岩隧道大变形的基本特征。采用室内试验及现场量测等手段,综合分析确定了围岩物理力学参数,定量分析了洞室周边产生塑性区的条件、塑性区及洞壁位移的影响因素、塑性区半径与洞壁位移的关系。以现场量测数据为依托,结合理论计算,参考以往类似隧道经验,分别考虑了围岩的相对变形、强度应力比、原始地应力、弹性模量作为分级指标,并提出了综合系数α指标,采用综合指标判定法给出了大变形的分级标准,以及相应的防治措施。     

特长山岭隧道大变形段施工技术

介绍了大相岭隧道（俗称泥巴山隧道）软弱围岩挤压变形控制施工技术,指出该工程由于采用了有效的支护技术、开挖顺序、超前地质预报和相应的围岩量测,避免了因围岩挤压发生的变形侵限及塌方,提供了同级围岩施工先例。     

基于遗传优化支持向量机的软岩隧道围岩变形预测

软岩隧道施工过程中,围岩极易出现大变形和坍塌现象,如何有效地对隧道围岩大变形进行预测,已成为保障隧道施工安全的重要手段之一。本文以象山隧道为工程背景,采用遗传算法优化支持向量机参数,建立了隧道变形的遗传支持向量机模型,对象山隧道围岩的拱顶沉降和变形收敛进行了预测。模型预测值与实际测量值的对比结果表明,两者之间的误差较小,预测精度较高,所建立的GA-SVM模型可为隧道施工安全和支护结构的优化提供技术支撑。     

云顶隧道敞开式隧道掘进机通过断层破碎带施工技术

马来西亚东海岸铁路项目云顶隧道右线隧道掘进机（TBM）掘进期间,遇到破碎围岩、软弱围岩、泥岩、断层以及深度塌腔等多种不良地质段,通过分析TBM通过的不良地质情况,对施工方案进行介绍,并对实际施工过程中应对不良地质的施工技术进行探析,可供同类不良地质工程借鉴。     

基于掘进性能的TBM施工围岩综合分级方法

传统围岩分级方法侧重于围岩的稳定性,对于TBM施工隧道工程,围岩与TBM均扮演重要角色,有必要建立一套服务于TBM隧道工程的围岩分级新方法。依托引汉济渭引水隧洞工程的现场数据,对场切深指数FPI与地质参数、掘进参数的相关性进行分析,建立TBM隧道的围岩可掘性分级;对影响TBM利用率的主要地质因素进行分析,建立TBM隧道的适应性分级。综合考虑工程的围岩可掘性及TBM适应性,以施工速度为指标,建立基于掘进性能的TBM施工围岩综合分级。分级选取岩石强度、岩体完整性、地下水状态、初始地应力状态、隧道轴线与主要软弱结构面夹角等5方面因素指标,对TBM推力、贯入度、利用率和施工速度进行影响关系综合分析。结果表明,新建立的TBM施工围岩综合分级方法可以进行TBM掘进性能预测与工期、成本分析,有效解决开敞式TBM工程实用围岩分级问题。     

Physical model simulation of rock-support interaction for the tunnel in squeezing ground

The existence of squeezing ground conditions can lead to significant challenges in designing an adequate support system for tunnels.Numerous empirical,observational and analytical methods have been suggested over the years to design support systems in squeezing ground conditions,but all of them have some limitations.In this study,a novel experimental setup having physical model for simulating the tunnel boring machine(TBM)excavation and support installation process in squeezing clay-rich rocks is developed.The observations are made to understand better the interaction between the support and the squeezing ground.The physical model included a large true-triaxial cell,a miniature TBM,laboratoryprepared synthetic test specimen with properties similar to natural mudstone,and an instrumented cylindrical aluminum support system.Experiments were conducted at realistic in situ stress levels to study the time-dependent three-dimensional tunnel support convergence.The tunnel was excavated using the miniature TBM in the cubical rock specimen loaded in the true-triaxial cell,after which the support was installed.The confining stress was then increased in stages to values greater than the rock’s unconfined compressive strength.A model for the time-dependent longitudinal displacement profile(LDP)for the supported tunnel was proposed using the tunnel convergence measurements at different times and stress levels.The LDP formulation was then compared with the unsupported model to calculate the squeezing amount carried by the support.The increase in thrust in the support was backcalculated from an analytical solution with the assumption of linear elastic support.Based on the test results and case studies,a recommendation to optimize the support requirement for tunnels in squeezing ground is proposed.     

Effect of adverse geological condition on TBM operation in Ghomroud tunnel conveyance project

With the planned length of 36 km, Ghomroud tunnel is one of the longest tunnels under construction in central Iran. About half or 18 km of this tunnel was excavated by a double shield TBM. Several adverse geological conditions encountered, consisting of ground squeezing and face collapse, hindering TBM performance, and caused several TBM stoppages and jamming. This paper presents the impact of ground conditions on machine performance based on the information obtained from field observations and geotechnical site investigations. As built geological conditions are described while the method and results of tunnel convergence measurements and their impacts on tunneling operation is examined. Based on the detail study of the available geological information and tunnel convergence measurements, it was evident that the existence of weak structures in rock mass resulted in high rate of the convergence, which was the dominant factor in the TBM jamming. Since it was not possible to make observation and measurements of geological parameters when working in a lined tunnel built by a shielded machine, an attempt was made to correlate TBM operational parameters and ground convergence. The preliminary result of the analysis has indicated a good correlation among machine’s operational parameters and tunnel convergence. If the system is fully developed, these parameters can be used as an indicator of the potential for high rates of convergence. An early warning on ground convergence is essential for taking precautionary measures to avoid TBM from getting jammed by squeezing ground.     

水下盾构隧道抗震设计分析方法的适应性研究

 针对断面大、水头高，结构复杂的水下盾构隧道，通过分析其在横向和纵向结构特点，提出了合理的抗震设计方法。在地层条件较均匀的横断面，通过成层重复反射理论，计算出工程场地地层的实际地震响应，采用反应位移法对隧道典型断面进行地震反应分析，再将其结果与静力计算结果叠加后作为抗震设计的依据。纵向则考虑线状结构特点、沿隧道纵向地层的不均匀性、地震行波效应和边界效应等方面的因素，应用三维时程响应法加以计算分析。对2种方法的特点、适用条件和分析流程进行了系统阐述，并将其应用于越长江盾构隧道工程，揭示了该典型水下盾构隧道的动力响应特征及抗震的薄弱部位。     

Evaluating D&B and TBM tunnelling using NTNU prediction models

Drill and Blast (D&B) and Tunnel Boring Machine (TBM) are the two dominating excavation methods in hard rock tunnelling. Selection of the cost effective excavation method for a tunnel is a function of tunnel cross section area, rock conditions, tunnel length, availability of skilled labour and proper equipment, and project schedule. Over the past few decades, major technological development and technical advances have been achieved in both methods. Yet, in many tunnelling projects, choosing the excavation method is still a challenge and requires considering pros and cons of each method and estimating construction time, costs, as well as post construction and operation & maintenance, and related risk in the planning phase. In this study, the productivity and efficiency of the D&B and TBM options for excavating certain size tunnels have been examined. The analysis is based on recent NTNU prediction models for advance rate and unit excavation cost for given ground conditions and tunnel geometry. For excavation of large size tunnels in very hard rock, the D&B method seems to be the cost effective choice irrespective to tunnel geometry. This is compared to smaller long tunnels with good boreability were the TBM has higher advance rate. The tunnel size and rock conditions have higher impact on the TBM performance and costs than for D&B. This refers to lower risk of using D&B where the use of this method is otherwise justified.     

An appraisal of TBM performances in Turkey in difficult ground conditions and some recommendations

The geology of Turkey is very complex and major Northern and Eastern Faults including minor faults associated to these faults create tremendous problems, like squeezing of the TBM, excessive water ingress, TBM face collapses, as encountered in the Kargi power tunnel, the Dogancay energy tunnel, the Gerede water tunnel, and the Nur Dagi railway tunnel. Mixed ground conditions with ophiolites, graphitic schists and melanges with boulders are other fundamental difficulties leading to squeezing and blocking of the TBMs or even causing complete failures of the segments and abandoning of the tunnel. A typical example for tunnel abandoning is the Kosekoy high speed tunnel and an example for excessive TBM squeezing is the Uluabat energy tunnel. The affects of dykes in the Istanbul region is known well by practicing tunnel engineers. These andesitic rocks, make fractures in the country rock and cause several problems during TBM excavation like blocking the cutterhead and excessive disc cutter consumption. Typical examples are the Goztepe-Kadıkoy Metro tunnels, and the Melen water tunnel. The Beykoz utility tunnel is one of the most difficult tunnelling projects in Istanbul. Presence of clay minerals existing within the geologic formations is also one of the main reasons clogging the cutterhead of TBM as encountered in the Suruc water project. The effects of complex geology on the excavation efficiencies of different type of TBM’s used in the ten projects mentioned above are explained in this paper and some recommendations with a ground classification system for proper use of TBMs in faultyzones are given.     

水平向钻孔的海底隧道横向预排水系统数值模拟

 高水压、大渗流量的海底隧道而言，为防止涌水的事故发生，设计一高效的排水系统是非常重要的。大多数海底隧道的崩溃都和高水压、大渗流量有着密切联系。为了寻求其中的规律，研究了一系列的TBM和NATM隧道案例。案例研究结果表明，如果在隧道挖掘前能够预测渗流量以及预先设置排水系统就能有效预防工程事故。据此，提出了新水平预排水系统。通过数值模拟计算，分析了在海底隧道的施工期，从隧道工作面通过排水孔泄水的效果。假设海底隧道的岩层覆盖层厚100 m，水深60 m，并假设设置水平预排水系统之后的地层渗透系数为0.003 6 m/h。计算结果表明，隧道顶点总水头减少了60%，隧道拱脚线总水头减少了53%。当排水管直径为5 cm、地层渗透系数为0.003 6 m/h时，为增强排水效果，排水管的长度不得超过250 m。数值分析及排水效果均表明，所提出的水平预排水系统能及时排水并减小水压力。在海底隧道建设方面，这个系统可为其提出一种新的解决方案。     

浅埋暗挖地铁站厅洞室开挖过程物理模型试验及土体变形规律研究

 据相似材料大比尺三维概念物理模型理论,高仿真度制作了成型盾构隧道地铁站厅洞室开挖试验物理模型。模拟了双盾构隧道之间开挖站厅洞室的全过程,研究站厅洞室、横通道开挖过程中模型地表沉降,土体的变形,盾构隧道及站厅洞室周围特征点的位移。模拟并研究混凝土加固桩对土体位移的影响,总结出土体的动态力学特征和变形规律,得出一些有益的认识和结论。对研究在已建成地铁双隧道间拓展开挖站厅空间的施工具有重要的参考意义。     

Case studies of TBM tunneling performance in rock–soil interface mixed ground

This paper investigates the performance of tunnel boring machines (TBMs) in rock–soil mixed-face ground based on TBM tunneling projects in Singapore. Currently several methods are available to estimate TBM tunneling performance in homogenous rock or soil. However, the existing models cannot be effectively applied to predict TBM penetration rate in mixed ground. The tunnels in this study were excavated in adverse mixed-face ground conditions. The geological profiles and the TBM operational parameters are compiled and analyzed. The influence of different geological face compositions on the performance of the TBMs is studied. The statistical analysis shows that there is a possible correlation between the mixed-face ground characteristics and the TBM advancement. Different approaches are used to find a reliable model. Finally, a method is proposed to predict the TBM performance in mixed-face ground for project planning and optimization.     

浅埋暗挖隧道施工引起的地表塌陷分析及其控制

 防控地表塌陷特别是海床塌陷是浅埋暗挖海底隧道施工的关键问题之一，一旦发生海床塌陷，海水可能大量涌入隧道，将造成灾难性后果。因此，明确地表塌陷的发生机制、诱发因素和相应的控制措施是浅埋暗挖隧道包括海底隧道安全施工的重要保证。以深圳地铁一隧道施工引起的两次地表塌陷事故为工程背景，根据普氏平衡拱理论，对浅埋暗挖隧道施工引起的地表塌陷进行深入的分析，明确地表塌陷的发生机制，并结合地层条件和施工情况给出了诱发地表塌陷的原因，在此基础上提出相应的控制技术，并在隧道后续施工中得到应用，取得了理想的控制效果。研究结果表明，严格按照浅埋暗挖法的基本原理和技术要点进行隧道施工，可以有效地避免地表塌陷事故的发生。研究成果对浅埋暗挖城市地铁隧道和海底隧道等类似工程施工预防地表塌陷具有一定的指导意义。