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When planning a TBM drive in squeezing ground, the tunnelling engineer faces a complex problem involving a number of conflicting factors. In this respect, numerical analyses represent a helpful decision aid as they provide a quantitative assessment of the effects of key parameters. The present paper investigates the interaction between the shield, ground and tunnel support by means of computational analysis. Emphasis is placed on the boundary condition, which is applied to model the interface between the ground and the shield or tunnel support. The paper also discusses two cases, which illustrate different methodical approaches applied to the assessment of a TBM drive in squeezing ground. The first case history—the Uluabat Tunnel (Turkey)—mainly involves the investigation of TBM design measures aimed at reducing the risk of shield jamming. The second case history—the Faido Section of the Gotthard Base Tunnel (Switzerland)—deals with different types of tunnel support installed behind a gripper TBM. 相似文献
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安徽省龙瀑隧道是我国首次采用半明半暗通透肋式拱梁异型结构,其隧道开挖是在山体浅表层进行暗洞开挖,既要考虑到隧道围岩本身的稳定性又要注意到隧道所在山体整体的稳定性.隧道开挖后地应力到底是如何释放的?目前在国内是个空白,研究通过资料整理,对位移变化较明显的两支多点位移计进行重点分析;根据经验反馈法分离出控制性结构面张开的位移;并通过数值模拟建立一个目标函数,将数值模拟中监测点的位移结果与修正后的实测监测点位移结果进行对比,最终确定了龙瀑隧道的最佳地应力释放率在60%~70%之间[1]. 相似文献
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挤压式盾构隧道施工引起的地表移动及变形 总被引:21,自引:0,他引:21
视挤压式盾构施工隧道引起的地表移动为一随机过程,应用随机介质理论对所引起的地表移动和变形进行了分析。工程实例分析表明,该分析方法效果良好。 相似文献
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G. Preisig A. Dematteis R. Torri N. Monin E. Milnes P. Perrochet 《Rock Mechanics and Rock Engineering》2014,47(3):869-884
Interception of aquifers by tunnel excavation results in water inflow and leads to drawdown of the water table which may induce ground settlement. In this work, analytical and numerical models are presented which specifically address these groundwater related processes in tunnel excavation. These developed models are compared and their performance as predictive tools is evaluated. Firstly, the water inflow in deep tunnels is treated. It is shown that introducing a reduction factor accounting for the effect of effective stress on hydrodynamic parameters avoids overestimation. This effect can be considered in numerical models using effective stress-dependent parameters. Then, quantification of ground settlement is addressed by a transient analytical solution. These solutions are then successfully applied to the data obtained during the excavation of the La Praz exploratory tunnel in the Western Alps (France), validating their usefulness as predictive tools. 相似文献
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采用解析法研究穿越地表建筑物浅埋隧道开挖引起的地表沉降。由无建筑物时岩土体开挖引起的地表沉降公式及半无限平面在均布荷载下的相对沉陷,推导出了穿越地表建筑物浅埋隧道施工引起的地表沉降公式,并通过实例验证了此方法的可行性。采用上述方法研究了地表建筑物的重量及其与浅埋隧道位置关系对地表沉降的影响,研究结果表明:浅埋隧道开挖引起的地表沉降随建筑物重量的增大而增大;建筑物中心到隧道轴线的水平距离是对地表沉降的一个重要影响因素,超过一定范围时建筑物的存在对地表沉降的影响可以忽略不计。研究结果可为类似隧道工程提供一定参考。 相似文献
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State of Stress in Tunnel Lining in Squeezing Rock Conditions 总被引:1,自引:1,他引:0
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The Manh Vu Jean Sulem Didier Subrin Nathalie Monin Judith Lascols 《Rock Mechanics and Rock Engineering》2013,46(2):231-246
In this paper, we analyse the convergence measurements recorded in a gallery excavated in severely squeezing ground. The procedure consists in a preliminary geometrical treatment of the raw data to evaluate the principal axes of deformation by assuming an elliptic deformation of the walls of the gallery. Then the convergence law proposed by Sulem et al. (Int J Rock Mech Min Sci Geomech Abstr 24(3):145–154, 1987a), which is extended to account for anisotropic closure, is fitted on the displacements along the two axes of the obtained ellipse. This procedure is more robust and relevant than fitting the convergence recorded on the most deforming segment or fitting the average value of the convergence along the various segments. An attempt is made to correlate the amount and the direction of anisotropic deformation with the lithology and some geological features described by the dominant discontinuity families. 相似文献
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Huang Zhen Liao Minxing Zhang Haoliang Zhang Jiabing Ma Shaokun Zhu Qixuan 《Geotechnical and Geological Engineering》2022,40(3):1387-1405
Geotechnical and Geological Engineering - Rock squeezing has a large influence on tunnel construction safety; thus, when designing and constructing tunnels it is highly important to use a reliable... 相似文献
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Rassoul Ajalloeian Batol Moghaddam Abdolazim Azimian 《Geotechnical and Geological Engineering》2017,35(2):747-763
One of the most important steps in designing underground structures is the evaluation of ground conditions in terms of squeezing potential and behavior of the geological structures. Generally, constructing a tunnel in the squeezing condition is a very slow and difficult task. Therefore, recognition and evaluation of the squeezing potential is very important in selecting a suitable excavation method and support, especially in weak rocks. This research is concerned with the assessment of squeezing potential along tunnel T4 of water conveyance system from Azad dam to Ravansar plain with the length of 11,380 m, located between Kurdistan and Kermanshah provinces, west of Iran. This tunnel is in an almost NS direction and flows through the contact zone of Iran and Arabic plates. According to the engineering geological investigations, the squeezing potential has been recognized as the most important difficulty in the excavation of tunnel T4. This conclusion can be explained by the several indicators including lithology, high disintegration of rock masses, alteration of rocks on the border of Iran and Arabic plates’ contact zone, low rock mass quality, high overburden, and highly jointed rock masses in a shuffle tectonic condition. This paper deals with the engineering geological and geomechanical properties of rock masses. Then, it evaluates squeezing intensity using empirical, semi-empirical, and analytical properties methods. The analysis conducted in these work shows that the tunnel excavation would encounter squeezing problems, which is most severe in region 2 due to the effects of the major young Zagros fault. 相似文献
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Interpretation of Core Extrusion Measurements When Tunnelling Through Squeezing Ground 总被引:1,自引:0,他引:1
Squeezing intensity in tunnelling often varies over short distances, even where there is no change in the excavation method
or lithology. Reliable predictions of the ground conditions ahead of the face are thus essential to avoid project setbacks.
Such predictions would enable adjustments to be made during construction to the temporary support, to the excavation diameter
and also to the final lining. The assessment of the behaviour of the core ahead of the face, as observed by means of extrusion
measurements, provides some indications as to the mechanical characteristics of the ground. If the ground exhibits a moderate
time-dependent behaviour and the effects of the support measures are taken into account, the prediction of convergence is
feasible. If the ground behaviour is pronouncedly time-dependent, however, convergence predictions become very difficult,
because core extrusion is governed by the short-term characteristics of the ground, which may be different from the long-term
properties that govern final convergence. The case histories of the Gotthard Base Tunnel and of the Vasto tunnel show that
there is a weak correlation between the axial extrusions and the convergences of the tunnel. By means of the case histories
of the Tartaiguille tunnel and Raticosa tunnel, it is shown that to identify potentially weak zones on the basis of the extrusion
measurements, careful processing of the monitoring data is essential: the analysis of the data has to take account of the
effects of tunnel support and time, and has to eliminate errors caused by the monitoring process. 相似文献
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浅埋暗挖隧道施工引起地表沉降的控制措施研究 总被引:2,自引:0,他引:2
以北京长安复线隧道浅埋暗挖工程为背景,对目前经常采用的台阶法开挖、小导管超前注浆及喷射砼三种技术措施,采用数值仿真技术,对其控制地表沉降的有效性进行了定量分析,可供设计、施工参考。 相似文献
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When planning a TBM drive in squeezing ground, the tunnelling engineer faces a complex problem involving a number of conflicting
factors. In this respect, numerical analyses represent a helpful decision aid as they provide a quantitative assessment of
the effects of key parameters. The present paper investigates the interaction between the shield, ground and tunnel support
by means of computational analysis. Emphasis is placed on the boundary condition, which is applied to model the interface
between the ground and the shield or tunnel support. The paper also discusses two cases, which illustrate different methodical
approaches applied to the assessment of a TBM drive in squeezing ground. The first case history—the Uluabat Tunnel (Turkey)—mainly
involves the investigation of TBM design measures aimed at reducing the risk of shield jamming. The second case history—the
Faido Section of the Gotthard Base Tunnel (Switzerland)—deals with different types of tunnel support installed behind a gripper
TBM. 相似文献
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主要介绍了在Ⅱ、Ⅲ类围岩中施工城市浅埋隧道的施工技术,以“短开挖、快封闭、强支护、勤量测”为指导,将隧道分成上、下两个台阶进行开挖,及时进行初期支护,保证施工始终处于安全状态。 相似文献
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S. M. Fatemi Aghda K. Ganjalipour M. Esmaeil Zadeh 《Geotechnical and Geological Engineering》2016,34(5):1487-1512
According to the International Society of Rock Mechanics, squeezing is a time dependent large deformation occurring during tunnel construction around the tunnel associated with creep caused by exceeding a limiting shear stress (Barla in ISRM News J 2:44–49, 1995). This research is conducted using a case study on the Nowsoud Tunnel, Iran. Being 14 km in length and 4.5 m in diameter, the tunnel is located in the western part of Iran near the Iraq border. Nowsoud tunnel, which was excavated using a double shield TBM, exhibited severe squeezing (with 8919 m) in its critical zone which resulted in excavation termination. In this research, the best approach for predicting squeezing among the recommended methods for reducing the damages caused by squeezing on TBM was determined. In this regard, approaches commonly used to predict squeezing are empirical, semi-empirical, and theoretical–analytical methods. Besides, these methods, numerical modeling is used to estimate convergence generated along the tunnel pathways, which is ultimately used to categorize squeezing. This paper compares squeezing prediction methods in 68 section of Nowsoud Tunnel. These 68 sections indicate that the empirical methods propose a general estimation/overview of squeezing. Among the semi-analytical approaches, the one proposed by Hoek and Marinos (Rock engineering in difficult rock conditions—soft rocks and karst, Taylor & Francis Group, London, pp 49–60, 2000) are compatible with the occurrence of squeezing in the critical zone. However, the degree of predicted squeezing is less than the real degree of squeezing in this zone. Based on the result of Aydan approach, 75 % of the tunnel sections are under squeezing condition. Theoretical–analytical approaches underestimate the possibility of squeezing in the critical zone. Barla?s approach (1995) demonstrated the possibility of squeezing in the critical zone with low intensity. The numerical computations in this paper were performed using Plaxis (version 8.5), a two-dimensional numerical program based on the finite element method. Plaxis results, classified by Hoek and Marinos (2000) method, show that 8800 m of the tunnel length is under the non-squeezing condition. According to all prediction methods, the squeezing zones depend on faulted zones, argillaceous limestone and shale formations such as J1Kh, J4Kh, J5Kh, and Kgr. These formations were identified with a high quantity of shale and argillaceous limestone. Bedding of these geological formations is thin and their geotechnical properties are weaker than those of limestone formations. On the other hand, non-squeezing zones depend on limestone formations such as J2Kh, J3Kh, J6Kh, Kabg, and Kbg. Moreover, all approaches predicted squeezing potential for the critical zone where TBM is jammed. 相似文献
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介绍了利用隧道施工的位移量测信息来选择计算模型的原理和方法。应用实例表明,本文所提出的方法有较好的应用前景。 相似文献