深部位移监测在偏压隧道中的应用

面临浅埋偏压隧道,如果处理不好,很容易引起质量问题。本文结合某在建隧道,简要分析了深部位移监测在偏压隧道中的应用,对于偏压隧道出现病害的治理有很好的指导作用。     

深部位移监测在偏压隧道中的应用

面临浅埋偏压隧道,如果处理不好,很容易引起质量问题。本文结合某在建隧道,简要分析了深部位移监测在偏压隧道中的应用,对于偏压隧道出现病害的治理有很好的指导作用。     

基于合理拱轴线的偏压隧道最优断面研究

偏压隧道是工程中常见的一种隧道形式，隧道的断面形状会影响到衬砌结构受力性能和围岩的稳定性。针对偏压隧道的断面形状优化设计，基于衬砌合理拱轴线，开展偏压隧道最优断面形状的研究。根据偏压隧道的工程特点，建立初始断面形状为圆形的偏压隧道有限元模型，计算得到隧道衬砌的弯矩、轴力和偏心距。进一步，以偏心距最小作为目标函数，通过反复调整衬砌轴线的位置，使衬砌轴线逐渐逼近合理拱轴线，从而获得偏压隧道的最优断面。在此基础上，对比研究偏压隧道优化前后衬砌的力学性能和隧道围岩的应力分布情况。结果表明，这种最优断面形状的偏压隧道极大改善衬砌结构受力状况，衬砌主要承受轴向压力作用，能够充分发挥混凝土材料的抗压性能，而且隧道围岩的应力分布均匀，避免了隧道围岩的应力集中。     

严重偏压浅埋隧道进洞施工技术

从地表处理、施作偏压挡墙、洞身开挖、初期支护、二次衬砌和防排水处理等方面详细介绍了广州—珠海城际轨道交通工程凤凰山浅埋偏压隧道进洞施工技术,指出施工中应注重环境保护,同时为偏压隧道提供了成功的进洞经验。     

小间距隧道施工应急处理探讨

结合卧龙沟2号隧道的施工情况,详细阐述了小间距、浅埋、偏压隧道重点难点控制性工程的应急处理措施,总结了左洞初支偏压形变、中夹岩应变、后行洞初支形变等处理关键技术,以确保隧道施工的安全性。     

公路隧道超浅埋偏压段技术探讨

结合忻州至阜平高速公路火焰山隧道实际施工经验,有针对性地提出一些超浅埋偏压段隧道处理措施,且应用效果良好,能够确保隧道建设及运营的安全,为今后超浅埋偏压隧道施工提供了经验。     

浅埋偏压隧道施工中深部位移监测技术探析

随着我国交通基础设施的快速发展,在实际工程中出现越来越多的浅埋偏压隧道,这增加了隧道工作者的施工难度和风险程度,严重影响了施工安全和施工进度,面临浅埋偏压隧道,如果处理得不好,则很容易引起隧道洞口段产生塌方、滑坡、冒顶,甚至隧道衬砌开裂等严重灾害。基于以上原因,结合工程实际,对某在建浅埋偏压隧道施工中深部位移监测技术进行分析,为偏压隧道出现的病害治理有很好的指导作用。     

大偏压小净距碳硅质板岩隧道零开挖进洞施工

通过对神河1号大偏压碳硅质板岩隧道进洞塌方原因、处理方案分析,探讨了大偏压小净距碳硅质板岩隧道零进洞施工应注意的问题,并提出相关建议,以确保隧道施工顺利进行。     

公路隧道洞口偏压段施工技术

根据吕梁市劝家山隧道的实际情况,制定了隧道洞口偏压段的施工方案,并从施工放样、联合支护、基底处理、拱圈施工等方面,阐述了具体的施工技术,有效解决了偏压状态下隧道整体产生位移的问题。     

浅埋偏压隧道进洞施工方法概述

从地表处理、偏压挡墙的施工、洞身开挖、初期支护、二次衬砌等方面介绍了浅埋偏压隧道进洞的施工方法，总结了监控量测程序，提出了质量控制措施，为类似工程提供借鉴。     

基坑开挖及上盖荷载对下卧隧道结构的影响分析

广州珠江新城核心区市政交通项目金穗路以北地下空间基坑位于地铁隧道正上方,基坑开挖、工程(人工挖孔)桩及上盖荷载施工对地铁隧道结构的影响为该工程的关键问题。为此,利用MIDAS/GTS建立有限元模型,对实际的施工工况进行模拟。研究结果表明:隧道结构处于中风化地层的变形量仅为强风化地层的1/3;近距离人工挖孔桩、隧道上方上盖荷载施工及增大转换梁的刚度均能在一定程度上约束隧道的水平和竖向变形;土体偏压开挖对隧道结构水平方向变形影响较大。根据研究结果,提出对下方既有隧道的保护措施,以确保地铁结构安全和正常运营,为设计和施工提供指导意见。     

特大断面连拱隧道中墙偏压机制及施工影响分析

 中墙作为连拱隧道的主要承载结构,自身的稳定性直接影响着隧道工程整体的稳定性,是连拱隧道设计和施工的重点。中墙失稳的主要力学原因是中墙受力不均而产生偏压失稳,因此,控制中墙稳定的关键是控制中墙偏压及其偏压程度。中墙偏压的出现源于隧道工程自身的地层偏压和非对称式施工产生的施工偏压,根据中墙受力状态可以确定地层偏压、施工偏压下中墙偏压的条件及偏压发生部位;利用有限元计算方法对地层偏压、施工偏压条件下不同施工工序进行计算,分析不同工序对中墙偏压的影响;根据得到的规律对施工工序进行优化分析;最后,给出双向八车道连拱隧道的工程实例。     

Three-dimensional numerical simulation of a mechanized twin tunnels in soft ground

The increase in transportation in large cities makes it necessary to construct of twin tunnels at shallow depths. Thus, the prediction of the influence of a new tunnel construction on an already existing one plays a key role in the optimal design and construction of close parallel shield tunnels in order to avoid any damage to the existing tunnel during and after excavation of the new tunnel.Most of the reported cases in the literature on parallel mechanized excavation of twin tunnels have focused on the effects of the ground condition, tunnel size, tunnel depth, surface loads, and relative position between the two tunnels on tunnel behaviour. The numerical investigation performed in this study, using the FLAC^3D finite difference element programme, has made it possible to include the influence of the construction process between the two tunnels. The structural forces induced in both tunnels and the development of the displacement field in the surrounding ground have been highlighted.The results of the numerical analysis have indicated a great impact of a new tunnel construction on an existing tunnel. The influence of the lagged distance between the two tunnels faces has also been highlighted. Generally, the simultaneous excavation of twin tunnels causes smaller structural forces and lining displacements than those induced in the case of twin tunnels excavated at a large lagged distance. However, the simultaneous excavation of twin tunnels could result in a higher settlement above the two tunnels.     

铁路隧道仰拱施工控制

针对仰拱是隧道结构的主要组成部分之一,它是隧道结构的基础,结合太中银铁路兴旺峁隧道仰拱施工的实例,着重说明了铁路隧道仰拱施工的主要注意事项及相应的处理措施,从而确保该隧道仰拱施工质量。     

锦屏二级水电站深埋长隧洞群的建设和工程中的挑战性问题

锦屏二级水电站大型深埋隧洞群由4条引水隧洞、2条辅助洞及1条施工排水洞组成,隧洞群总长约118 km,具有埋深大、洞线长、洞径大、地应力水平高、工程地质条件极其复杂、施工布置困难等特点,是目前世界上己建、在建总体规模最大、综合难度最大的水工隧洞群工程。隧洞群建设中面临地下水预报与处理、岩爆防治等关键技术问题。通过对锦屏二级水电站深埋隧洞群建设中遇到岩爆及突涌水工程治理等工程应用实例进行研究总结,提出下一步工程中所面临的挑战及应对措施。锦屏二级水电站工程深埋长隧洞的建设所取得的经验,可为类似工程提供有益的借鉴。     

Numerical investigation of underlying tunnel heave during a new tunnel construction

This paper presents a case study of protecting existing tunnels during the construction of a new cut-and-cover tunnel above in Nanjing, China. Various construction measures, including sequential excavation, jet grouting, and a pile-slab retaining system were performed to control the heave of existing tunnels. Furthermore, a numerical analysis using a finite difference program, FLAC3D, was conducted to investigate the influence of different construction schemes on the tunnel heave. Finally, a comparison between numerical results and field measurements were carried out to study the influence on the tunnel heave from various factors, such as the ground reinforcement depth, excavation sequence, and the skew angle between new tunnel and existing tunnels. The results show that when the excavation volume is small, the uplift values of existing tunnels increase nonlinearly with the increasing excavation width of each step. The pile-slab retaining system combining with ground treatment method can control the tunnel heave within the required limits. The optimum ground treatment scope is about 1.5 times of the excavation depth in this project. Compared to other construction schemes, the tunnel heave will be the smallest under a staggered segmentation excavation method starting from the sides to the center.     

Prevention and treatment technologies of railway tunnel water inrush and mud gushing in China

Water inrush and mud gushing are one of the biggest hazards in tunnel construction. Unfavorable geological sections can be observed in almost all railway tunnels under construction or to be constructed, and vary in extent. Furthermore, due to the different heights of mountains and the lengths of tunnels, the locations of the unfavorable geological sections cannot be fully determined before construction, which increases the risk of water inrush and mud gushing. Based on numerous cases of water inrush and mud gushing in railway tunnels, the paper tries to classify water inrush and mud gushing in railway tunnels in view of the conditions of the surrounding rocks and meteorological factors associated with tunnel excavation. In addition, the causes of water inrush and mud gushing in combination of macroand micromechanisms are summarized, and site-specifc treatment method is put forward. The treatment methods include choosing a method of advance geological forecast according to risk degrees of different sections in the tunnel, determining the items of predictions, and choosing the appropriate methods, i.e. draining-oriented method, blocking-oriented method or draining-and-blocking method. The treatment technologies of railway water inrush and mud gushing are also summarized, including energy relief and pressure relief technology, advance grouting technology, and advance jet grouting technology associated with their key technical features and applicable conditions. The results in terms of treatment methods can provide reference to the prevention and treatment of tunnel water inrush and mud gushing.     

盾构施工中不利工况下隧道结构的力学行为

钱江隧道是目前世界上最大直径的软土盾构隧道工程之一。采用有限元分析方法,对盾构掘进与管片拼装阶段中常见的K块挤入、壁后注浆缺陷、环面不平整、盾构纠偏或曲线推进等不利工况,分析隧道结构的受力和变形特征。结果表明:K块挤入对邻接块的受力状态的影响最为明显,K块宜位于衬砌环腰线以上区域。环面不平整、壁后注浆缺陷和盾构纠偏(或曲线推进)将显著影响盾构推进阶段的衬砌的受力和变形。当环面不平整超过1 mm时,壁后注浆缺陷超过1 m²,或盾构纠偏顶部推力最大时,极易造成管片结构局部开裂、破损。在今后的设计和施工控制中应予以充分考虑。     

近距离交叠隧道施工影响的数值模拟

由于地质条件的限制及地下空间的综合开发利用,在工程中有时不可避免地产生近距离交叠隧道.对于这种型式的隧道,新建隧道是在既有隧道完成之后修建的,新建隧道的施工势必影响既有隧道结构的受力状态,引起既有隧道变形.本文应用ANSYS有限元程序采用三维弹塑性数值计算方法对某新建铁路隧道下穿既有高速公路隧道的施工过程进行了模拟,揭...