共查询到20条相似文献，搜索用时 15 毫秒
1.
CHEN Jun-sheng MO Hai-hong 《浙江大学学报(A卷英文版)》2006,7(11):1864-1869
INTRODUCTION Shield tunnel method has become the most pre- ferred method in city tunnel construction because of its excellent attributes: little effect on surrounding environment, fast and safe construction, outstanding performance in earthquake resistance, etc. (Zhang et al., 2004). In different shield tunnels, the arrangement and number of segments are different, but the whole assembling process is generally the same. The as- sembling process begins with A2P, then A1P, A3P, BP, CP, … 相似文献
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Dong-ming Yan Hua-wei Yin Cheng-lin Wu Yan-long Li Jason Baird Gen-da Chen 《浙江大学学报(A卷英文版)》2016,17(9):689-701
In this study, two full-size concrete walls were tested and analyzed to demonstrate the effectiveness of a chemically reactive enamel (CRE) coating in improving their mechanical behavior under blast loading: one with CRE-coated rebar and the other with uncoated rebar. Each wall was subjected in sequence to four explosive loads with equivalent 2, 4, 6-trinitrotoluene (TNT) charge weights of 1.82, 4.54, 13.6, and 20.4 kg. A finite element model of each wall under a close-in blast load was developed and validated with pressure and strain measurements, and used to predict rebar stresses and concrete surface strain distributions of the wall. The test results and visual inspections consistently indicated that, compared with the barrier wall with uncoated reinforcement, the wall with CRE-coated rebar has fewer concrete cracks on the front and back faces, more effective stress transfers from concrete to steel rebar, and stronger connections with its concrete base. The concrete surface strain distributions predicted by the model under various loading conditions are in good agreement with the crack patterns observed during the tests. 相似文献
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李彦民 《福建工程学院学报》2019,(6):539-544
为研究地面线路运营对下穿盾构隧道结构的影响规律,基于相似比理论建立室内大型试验模型,模拟上部列车荷载作用下土层及其内部盾构隧道结构的受力变形过程,总结变形规律。结果表明,模型试验能够较好地反映外部荷载影响下土层以及内部盾构隧道结构的受力和变形特性;地表列车荷载在土层传递过程中,同一层面上沿地面线路方向的土压力大于两侧土压力,远离线路的地层受列车荷载影响相对较小,同一竖向截面土压力变化量由上至下逐渐减小,即外部荷载对浅层土的影响明显大于深层土;盾构隧道在地表列车行驶过程中,环向出现背车面受拉迎车面受压的受力特性,呈斜向压扁,纵向应变从中间交叉点向盾构隧道两侧逐渐减小,呈下凹压弯;盾构隧道埋深越小,受地表荷载影响越显著,增大一倍埋深对应纵向应变最大值减小约44.5%。 相似文献
4.
张新 《石家庄铁路工程职业技术学院学报》2014,(1):44-48
以用于西安地铁一号线盾构施工的长安一号盾构机为例,对土压平衡盾构机的渣土改良系统基本原理和构成进行分析,对常见故障进行归纳分析,并阐述常见故障的产生原因和解决办法。 相似文献
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以南宁地铁一号线南湖段下穿隧道为工程背景,建立隧道开挖的三维有限元模型,通过数值分析,得到盾构施工过程中地层变形的分布规律,讨论盾构施工过程中注浆压力对地表沉降、水平位移及拱顶位移的影响,分析掌子面压力对地表隆起的影响规律。研究结果表明,注浆压力对地表变形会产生明显的影响,随着注浆压力的增大,地表沉降及水平位移明显减小。当掌子面压力大于0.1 MPa时,会引起掌子面前方土体产生向上的位移,地表隆起量随掌子面压力的增加而增大。 相似文献
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倪振利 《石家庄铁路工程职业技术学院学报》2014,(2):74-77
盾构机是城市地铁和隧道施工的主要机械装备,盾构机各项参数的设定对于掘进速度和施工质量影响重大。从盾构机刀盘扭矩和转速、千斤顶总推力、推进速度、螺旋输送机转速和压力、注浆流量和压力、加泥加泡沫流量和压力等参数分析入手,详细分析各项参数的设置对掘进性能的影响。并以北京地铁盾构施工为例,设计各项参数优化的具体实现思路,为盾构施工的科学组织和优化管理提供理论指导。 相似文献
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Applying stiffness migration method, a 3D finite element mechanical model is established to simulate the excavation and advance processes. By using 3D nonlinear finite element method, the tunnel boring machine (TBM) excavation process is dynamically simulated to analyze the stress and strain field status of surrounding rock and segment. The maximum tensile stress of segment ring caused by tunnel construction mainly lies in arch bottom and presents zonal distribution. The stress increases slightly and limitedly in the course of excavation. The maxi-mum and minimum displacements of segment, manifesting as zonal distribution, distribute in arch bottom and vault respectively. The displacements slightly increase with the advance of TBM and gradually tend to stability. 相似文献
8.
矫永刚 《福建工程学院学报》2020,(1):46-52
以滨海软土地层中盾构隧道平行上穿既有隧道为背景,通过数值仿真软件对开挖动态过程进行了精细化模拟,研究盾构隧道施工顶推力对周边地层及其内部既有隧道受力变形的影响。结果表明,在新建隧道上穿施工过程中,开挖扰动对地层的影响范围主要集中在距离开挖面-1.0~1.5D区域内(D为盾构隧道外径),扰动效果以新建隧道轴线为中心呈环状向外扩散,盾构顶推力从0.1MPa增至0.4MPa时,地表变形及1.0D范围内地层压力均增大20%以上;新建隧道平行上穿既有隧道过程中,既有隧道断面变形从横向鼓曲变为竖向拉伸,且整体出现上浮现象,顶推力达0.3MPa后,既有隧道拱底和拱顶隆起速度增加,以拱底为基准,顶推力自0.1MPa增加至0.4MPa时,隧道上浮量增大34.2%;施工过程中除保证常规地表变形监测外,对于近接平行上穿施工还需加强对既有隧道竖向变形的监控,必要时采取结构加固措施和施工参数综合调整办法,以降低开挖扰动对周边地层和结构物的影响。 相似文献
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The stress and the elastic deflection of internal ring gear in high-speed spur planetary gear units are investigated. A rim thickness parameter is defined as the flexibility of internal ring gear. Six evenly spaced linear springs are used to describe the fitting status between internal ring gear and the gearcase, The finite element model of the whole internal ring gear is established by means of Pro/E and ANSYS. The loads on meshing teeth of internal ring gear are applied according to the contact ratio and the load-sharing coefficient. With the finite element analysis （FEA）, the influences of flexibility and fitting status on the stress and elastic deflection of internal ring gear are predicted. The simulation reveals that the principal stress and deflection increase with the decrease of rim thickness of internal ring gear. Moreover, larger spring stiffness helps to reduce the stress and deflection of internal ring gear. Therefore, the flexibility of internal ring gear must be considered during the design of high-speed planetary gear transmissions. 相似文献
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结合广州市轨道交通三号线盾构隧道穿越广深铁路轨道群的施工实际经验,介绍了所采用的土压平衡盾构施工技术,并指出了常见问题及其对策和预防措施,对类似的地质条件下跨地铁段的设计和施工有一定的参考价值. 相似文献
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双护盾掘进机是一种高速、安全、自动化的隧洞工程施工机械,在实际工程中得到了广泛的应用。通过对其循环施工过程的深入研究,建立了双护盾掘进机循环运行网络模拟模型。采用循环运行网络理论,结合计算机模拟技术,开发了双护盾掘进机施工模拟程序。对一个工程实例进行了模拟分析,得到了此施工方案的施工净工期、净成本、掘进机掘进效率。 相似文献
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以ANSYS通用有限元为手段,使用非线性分析方法,对纤维缠绕复合材料压力容器进行有限元分析,在此模型基础上进一步研究了压力容器的渐进损伤,以失效因子为参数,讨论了失效单元逐层失效的过程。结果表明,复合材料压力容器在2.0MPa时树脂完全开裂,最初纤维断裂出现在应力为8.1MPa的桶身与封头连接处,而后经向纤维逐渐断裂,此位置最终在8.9MPa下纤维全部断裂。 相似文献
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王勇 《石家庄铁路职业技术学院学报》2021,(1):78-83
在合肥轨道交通2号线土建TJ04标段的东一环路站到铜陵路站区间采用盾构接收施工的背景下,对复杂环境下采用改性水玻璃来注浆加固端头土体的关键技术进行阐释,准确分析盾构机在粉细砂层进洞和出洞的注意事项和关键要点,这有利于施工人员针对性的施工,确保盾构机顺利进出洞。同时,这还能有效控制其对周边土质的影响,不致影响周边建筑的稳定性和安全性。 相似文献
14.
王磊 《石家庄铁路工程职业技术学院学报》2011,(4):57-59
在长距离掘进过程中,盾尾密封刷可能会由于盾尾密封油脂注入不足、盾构机姿态调整过猛、同步注浆砂浆在盾尾凝结等因素致使盾尾密封刷损坏,影响到施工的安全与施工质量。就洞内盾尾更换技术进行总结。 相似文献
15.
研究目的：预测保护层开裂的时间以及分析锈胀参数
研究方法：基于混凝十的各向异性损伤,建立考虑钢筋腐蚀产物混凝十三者不同力学性能的钢筋锈胀导致保护层开裂的数学模型。模型考虑了腐蚀产物对钢筋混凝土界面区的孔隙和混凝十开裂裂缝的填充效应,采用了非线性分析算法,预测了开裂过程中每一时刻混凝土构件的应变与位移场以及混凝土保护层开裂时间,最后将模型预测值与试验值进行对比。
1.当混凝土出现裂缝之后,随着腐蚀产物对裂缝的填充,混凝土的环向拉应变的增长速率减缓;2.选定钢筋的型号、直径以及混凝土的强度之后,可通过增大保护层的厚度来减小钢筋锈胀开裂的风险。 相似文献
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The seismic behaviors of an integral concreting frame, a light steel storey-adding frame and a storeyadding frame strengthened with carbon fiber reinforced polymer(CFRP)were investigated under low-cycle and repeated load(scale 1∶3). The failure characteristics, hysteretic behavior, rigidity degeneracy, deflection ductility and energy-dissipation capacity of the three specimens were compared. The test results reveal that chemicallybonded rebar technique can meet the requirements of storey-adding engineering. The carrying capacity, the deflection ductility, the energy-dissipating capacity and seismic performance of the light steel storey-adding frame are higher than those of the integral concreting frame, and they are the highest in the storey-adding frame strengthened with CFRP. 相似文献
18.
Analysis of structural response under blast loads using the coupled SPH-FEM approach 总被引：3，自引：0，他引：3
A numerical model using the coupled smoothed panicle hydrodynamics-finite element method （SPH-FEM） approach is presented for analysis of structures under blast loads. The analyses on two numerical cases, one for free field explosive and the other for structural response under blast loads, are performed to model the whole processes from the propagation of the pressure wave to the response of structures. Based on the simulation, it is concluded that this model can be used for reasonably accurate explosive analysis of structures. The resulting information would be valuable for protecting structures under blast loads. 相似文献
19.
张萍 《廊坊师范学院学报(自然科学版)》2014,(3):66-68
针对混凝土结构中钢筋的锈蚀问题,总结了锈蚀钢筋力学性能的研究方法、锈蚀对钢筋力学性能的影响及锈蚀钢筋力学性能的变化规律等研究现状,提出了有待继续研究的问题,为进一步建立锈蚀钢筋模型和加强锈蚀钢筋防护奠定基础. 相似文献
20.
In most studies of tunnel boring machine(TBM)tunnelling, the groundwater pressure was not considered, or was simplified and exerted on the boundary of lining structure. Meanwhile, the leakage, which mainly occurs in the segment joints, was often ignored in the relevant studies of TBM tunnelling. Additionally, the geological models in these studies were simplified to different extents, and mostly were simplified as homogenous bodies. Considering the deficiencies above, a 3D refined model of the surrounding rock of a tunnel is firstly established using NURBS-TIN-BReP hybrid data structure in this paper. Then the seepage field of the surrounding rock considering the leakage in the segment joints is simulated. Finally, the stability of TBM water diversion tunnel is studied coupled with the seepage simulation, to analyze the stress-strain conditions, the axial force and the bending moment of tunnel segment considering the leakage in the segment joints. The results illustrate that the maximum radial displacement, the minimum principal stress, the maximum principal stress and the axial force of segment lining considering the seepage effect are all larger than those disregarding the seepage effect. 相似文献