共查询到20条相似文献，搜索用时 109 毫秒
1.
基于数值模拟方法,对厦门海底隧道施工进行优化分析。在侧压力系数为0.6和0.9情况下,首先针对3种常用施工方法——全断面开挖法、上下台阶法和台阶分部开挖法进行计算分析,通过比较隧道洞周关键点位移及洞周塑性区分布,得到全断面开挖对围岩的扰动较小;然后,通过计算分析不同台阶长度对隧道的稳定性的影响,得到上下台阶开挖台阶步距为10 m左右较为合理的结论,对海底隧道的施工具有一定的指导意义。 相似文献
2.
三台阶七步开挖法作为三台阶法的延伸,正越来越多地应用到大断面隧道施工中。以兰渝铁路香木湾隧道工程为例,对三台阶七步开挖法的特点、施工组织、工艺流程、施工要点等进行了详细的介绍。 相似文献
3.
从理论和实践对隧道开挖方法进行研究，探讨三种开挖方法，即全断面法、台阶法及导洞法的应用条件及其优点，正确选择开挖方法应考虑的主要因素。对地矿系统在隧道施工中推广新技术、新工艺和加强管理等方面提出了建议。 相似文献
4.
5.
6.
三车道高速公路隧道通常跨度较大、高跨比较小属于大跨扁平隧道。这种结构型式对围岩稳定和结构受力均产生不利影响,因此施工中有必要通过开挖方案比选确定合理的开挖方法。江苏省宁波-常州高速公路茅山东隧道为上下行分离式双向6车道浅埋大跨扁平隧道。对于破碎的Ⅳ级围岩,针对设计阶段拟采用CRD法和实际施工采用下断面左右分部台阶法的开挖方案在设计支护条件下的三维数值模拟,从理论上分析了下断面左右分部台阶法是可行的。与实际施工过程的监控量测结果进行对比分析,进一步证实了实际开挖方案的合理性。研究成果可以为同类工程的设计与施工提供理论参考。 相似文献
7.
软弱围岩隧洞施工性态的力学模拟与分析 总被引：35，自引：6，他引：35
本文着重对软弱围岩隧洞施工中的力学性态进行了计算机模拟和分析。文中除提出了考虑隧洞开挖面时空效应的三维分析模型外，还计入岩体流变时效，进行了弹－粘塑性数值计算。其中，研讨了开挖面推进过程中洞室围岩与错喷支护的相互作用以及设置整筑式二次内衬的影响。用所建议的力学模型和编制的程序软件，结合某实际工程，分别就洞室上下台阶法分部开挖、全断面法一次开挖和侧壁导坑法扩大开挖等三种最常见的隧洞施工作业方式进行了模拟分析，并将计算成果与现场实测数据作了比较验证。 相似文献
8.
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。 相似文献
9.
拟建的某洞库工程开挖断面101 m2，采用钻爆法施工修建。介绍了采用的光面爆破参数、微差爆破、间隔装药结构、复式楔形掏槽等施工工艺。 相似文献
10.
超大断面铁路隧道施工断面综合荷载释放过程研究 总被引：3，自引：0，他引：3
隧道开挖扰动会使影响范围内的围岩发生松弛,同时还产生一定的荷载作用于隧道结构。而在隧道开挖面推进时,作用于隧道结构上的荷载在应力调整过程中不断释放,最终在隧道结构及围岩达到稳定状态后荷载释放过程同时结束。通过数值分析及模型试验,对超大断面铁路隧道施时的隧道断面整体荷载释放过程进行了相关研究。研究了台阶法开挖过程中隧道洞壁不同特征点的荷载变化规律,并定义了能够表征隧道施工过程断面整体荷载释放状态的断面综合荷载释放率和荷载释放差异系数的概念,通过两者对隧道开挖断面整体荷载释放状态进行分析总结。在随后进行的隧道施工过程地质力学模型试验中,通过对开挖面推进洞壁不同位置围岩径向压力的变化规律进行监测,证明了数值模拟得到的结论,并进一步说明在隧道开挖的荷载释放过程研究中,应将整个断面作为研究对象,分析断面整体荷载释放状态,才能对隧道施工中的荷载释放过程有一个更加全面的认识。 相似文献
11.
求水山隧道下穿机荷高速段新奥法施工有限元计算 总被引：5，自引：0，他引：5
结合求水山隧道的暗挖法施工方案,对软土地区浅埋隧道下穿高速公路的施工过程进行了有限元模拟,以用于评价按该施工方案施工时对其上部高速公路的影响。由于该段隧道最小埋深仅4 m,且上部还有高速公路车辆荷载,因此,在设计时采用了新奥法结合管棚工法的方案。有限元建模使用平面应变单元,通过引入应力释放分析步和使用追踪单元等方法充分体现了新奥法的特点,并通过设置耦合和弹簧的方法实现了管棚工法的模拟,在计算中还考虑了开挖顺序和支护顺序的影响。研究结果表明：对于上部有荷载的浅埋暗挖隧道,控制衬砌的水平向变形能改善衬砌环的工作状态,因此,可显著减少开挖引起的隧道顶面沉降,新奥法结合管棚工法可较好地控制该类型隧道开挖引起的地表沉降变形。 相似文献
12.
对于高边坡、大型地下洞室、深基坑等逐层开挖工程,开挖形象具有动态变化的特点,工程形象变化大、开挖持续时间长、开挖面位置不断变化,开挖面地质信息必须及时采集,而传统的静态三维影像建模方法难以满足要求。本文以典型的逐层开挖工程——乌东德水电站大坝建基面边坡为研究对象,探索出一套三维影像建模方法,通过无人机倾斜摄影结合像控点测量、数据处理、模型构建,获取建基面整体三维影像。影像成果质量优良,位移偏差一般为5.1~7.9 cm,精度满足一般工程需要。此三维影像建模方法为工程信息存储、分析、展示和后期应用奠定了基础,取得了良好效果。 相似文献
13.
Nazmi Erhan Yasitli 《Arabian Journal of Geosciences》2013,6(7):2699-2708
As a result of urbanization all over the world, complicated transportation system have been constructed to supply the need of the public transport. Metro tunnel is the most important effective solution method for public transportation. However, the surface settlement around the metro line in urban areas should be within the allowable limits and it should not damage nearby structures. The tunnel excavation and the support system have to provide a reliable working condition for the workers and the people living along the metro line. Although New Austrian Tunneling Method (NATM) is a very useful method in tunnel excavation, it may be insufficient in weak rock condition. Umbrella Arch Method (UAM) has been recently a viable alternative in various important areas. In this paper, the results of 3-D numerical modeling of surface settlement at the transition zone in Istanbul Metro excavated by NATM and UAM are presented by using a finite difference code called FLAC3D. The results showed that umbrella arch pipe is very effective to minimize the surface settlement. According to the actual measurement result and numerical modeling result, umbrella arch pipe reduced the surface settlement by 71% and 63%, respectively. In addition, the numerical modeling result represented 79.5% of the actual value obtained from in situ for NATM region and 86.0% of in situ value for UAM region. 相似文献
14.
Stability analysis of shotcrete supported crown of NATM tunnels with discontinuity layout optimization 
下载免费PDF全文
下载免费PDF全文 For tunnel constructed by New Austrian Tunnelling Method, the crown is the upper part of tunnel section, constructed during excavation process and supported by shotcrete. The stability of the crown has great influence on the safety of tunnel itself and the buildings above, which correlates, among others, with geometrical setup of tunnel and material properties of shotcrete and soil/rock. In this paper, aiming at analyzing the stability of shotcrete supported crown, a recently presented numerical method discontinuity layout optimization is adopted, which introduces a great amount of potential discontinuities cross over one another and provides a wide search space for efficient upper limit analysis. In the analysis, a well‐established hydration model of cementitious material is implemented for accounting the hydration of shotcrete. Then assumptions based on convergence‐confinement method are used for accounting the 3‐dimensional effect in 2‐dimensional analysis, finally providing time‐space–dependent assessments of stability of shotcrete supported crown. 相似文献
15.
湿陷性黄土地区岩土工程往往涉及大量挖方填方工程，极易引发一系列的地面沉降和植被破坏问题。本文基于SBAS-InSAR技术结合遥感数据处理对延安新区平山造城工后地面沉降及植被恢复特征进行了分析。首先，通过目视解译及DEM提取，获取工程基本特征；随后，基于SBAS-InSAR技术对新区工后地面沉降进行探测；最后，利用遥感提取新区的NDVI时序数据。结果表明:(1)延安新区建筑工程建设滞后挖填方工程约2a，填方区域沿着原始地形的沟谷展布，挖填方体最大厚度均超过90m；(2)延安新区主要沉降区为填方区域，2017~2018年最大沉降速率达45mm ·a-1，主要建筑工程所处的挖方区无明显地面沉降，工程边坡大多处于稳定状态；(3)延安新区2013~2015年NDVI平均值增长230%，2015~2018年增长50%，植被恢复明显。延安新区平山造城工程的规划建设合理的规避了地面沉降及缓解了生态环境恶化，研究成果可为类似工程建设提供科学参考依据。 相似文献
16.
论述了考虑开挖卸荷效应的二维位移反分析方法。对龙滩水电站左岸岩质边坡1-1剖面进行地质概化、施工开挖分区和开挖扰动分区,建立有限元计算模型。根据试验和现场实测资料,确定待反演得参数和取值范围,通过二维弹塑性有限元方法与神经网络-遗传算法相结合反分析出岩体力学参数。基于该参数的正分析计算结果表明,计算位移与监测位移趋势一致,量值吻合。开挖面附近最大压应力约为1.0 MPa左右,开挖面附近基本上没有拉应力区。开挖完成后的塑性区主要分布在坡顶和开挖面及大断层附近,而且基本上发生在开挖损伤区和部分卸荷影响区。 相似文献
17.
Mehmet Ozcelik 《Geotechnical and Geological Engineering》2018,36(6):3437-3449
Mechanized tunnelling is a well-established tunnel construction method which allows constructing tunnels in various conditions including mixed ground conditions as well as tunnels in vulnerable urban areas. The selection of the excavator suitable for the geological structure is important in terms of realizing an efficient tunnel excavation. Tunnel excavation studies of Istanbul Kabatas–Mecidiyeköy Metro tunnels are implemented as a double tube. Geology in this section is composed of sandstone, siltstone, mudstone interbedded or as separate units along with dyke intrusions. Calcareous clay, clayey limestone, clayey sand are also rarely observed. Between the Kabatas–Mecidiyekoy tunnels includes two types of mechanical excavation methods namely tunnel boring machine (TBM) and new Austrian tunnelling method (NATM). Main purpose of this study is mixed ground and their impacts on mechanized tunnelling. At the end, some issues have been presented which seems to be important for the success of TBM and NATM in the mixed grounds. As the tunnel excavation studies continued, the problem of collapse on the ground surface of Barbaros Boulevard in Besiktas station increased the importance of tunnel excavation under mixed ground conditions. 相似文献
18.
基于边坡系统能量的原理,借助FLAC3D有限差分法内嵌FISH语言进行了三维露天矿边坡模型在开挖过程中能量计算的二次开发。将能量与突变理论相结合,以边坡系统的总耗散能作为状态变量,构建了边坡系统的能量耗散突变判别准则。以大孤山露天矿西北帮边坡为例,通过能量耗散突变分析、塑性区演化分析、安全系数变化分析及关键点位移分析可知,以上分析得到的边坡稳定性演化规律具有一致性,验证了提出的突变判别准则的适用性,研究结果表明：能量突变特征值 是露天矿边坡在第ki步开挖后发生失稳的充要力学条件;当进行至第6～8步开挖时,边坡局部岩体系统发生了失稳,且第7、8、9三个台阶受开挖扰动的影响较为严重,与现场的实际开挖情况相符,为预防露天矿边坡在开挖扰动过程中的局部围岩系统失稳提供了一定的理论支持。 相似文献
19.
Georg-Peter Jonuscheit 《Engineering Geology》1979,13(1-4):425-428
Experiences gained on the building of the City Railway turning loop, Stuttgart, Section 12, are described, where the new Austrian tunneling method is used in connection with the freezing technique. The Metro-tunnel lies in leached-out gypsum marl and unleached zones, respectively.
In a section of this tunnel within the leached-out gypsum marl the excavation was protected by a frozen soil roof in order to keep away any water seepage which could be dangerous for the excavation itself and for the buildings superimposed as well The drilling for the freeze pipes, the installation and operation of the freezing system and the tunnel driving including the erection of the final support are described. A point of special interest is the application of the shotcrete method as the shotcrete has to adhere to the frozen soil and has to harden sufficiently before the hardening process is interrupted by frost penetration. 相似文献
20.
Many problems in mining and civil engineering require using numerical stress analysis methods to repeatedly solve large models. Widespread acceptance of tunneling methods, such as New Austrian Tunneling Method, which depend heavily on numerical stress analysis tools and the fact that the effects of excavation at the face of a tunnel are distinctively three–dimensional (3D), necessitates the use of 3D numerical analysis for these problems. Stress analysis of a practical mining problem can be very lengthy, and the processing time can be measured in days or weeks at times. A framework is developed to facilitate efficient modeling of underground excavations and to create an optimal 3D mesh by reducing the number of surface and volume elements while keeping the result of stress analysis accurate enough at the region of interest, where a solution is sought. Fewer surface and volume elements mean fewer degrees of freedom in the numerical model, which directly translates into savings in computational time and resources. The mesh refinement algorithm is driven by a set of criteria that are functions of distance and visibility of points from the region of interest, and the framework can be easily extended by adding new types of criteria. This paper defines the framework, whereas a second companion paper will investigate its efficiency, accuracy and application to a number of practical mining problems. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献