鱼腹式箱梁横向受力的数值分析

介绍了箱梁横向受力的解析法与有限元分析法的特点。结合工程实例,对预应力混凝土鱼腹式连续箱梁的横向受力进行数值模拟,通过多工况计算分析,找出了最不利荷载分布模式,得到了各工况应力、内力以及裂缝开展的规律。计算表明,若桥面板横向不配置预应力钢束,则可能导致箱梁横向开裂,且裂缝超过规范容许值,从而影响整体结构的耐久性,该文计算方法是桥梁纵向设计计算的必要补充,所提出的合理化建议已被采纳,经试验及工程实践验证取得了良好的效果。     

PUSLE-EKKO地质雷达在隧道超前地质预报中的应用

阐述了地质超前预报的必要性和重要性,介绍了PUSLE-EKKO系列地质雷达系统构成及探测原理,举例说明PUSLE-EKKO地质雷达在公路隧道建设中的应用。     

铁路隧道使用凿岩台车与风钻钻爆的比较研究

为进一步分析研究高铁隧道凿岩台车与风钻钻爆的优劣及适用性问题,以郑万高铁小三峡隧道工程为依托,介绍风钻钻爆 的施工应用情况及凿岩台车钻爆在施工应用方面的制约因素,并从施工工效、人员配置、安全性、超欠挖控制、成本投入等方面对比 分析。 主要研究结论如下: 1)采用凿岩台车钻爆,在硬岩条件下钻爆速度较快,Ⅲ、Ⅳ级围岩可通过工法调整来提高凿岩台车的施 工效率,遇软弱围岩时应慎重选用; 2)凿岩台车钻爆与风钻钻爆相比,劳动强度低、节省劳动力、安全风险小等方面具有突出成效; 3)理论分析凿岩台车钻爆较风钻钻爆平均线性超挖小,但实际施工过程中却反之,可通过加强管理来缩小与人工钻爆之间的超挖 差距; 4)凿岩台车对风钻钻爆的优势显而易见,随着隧道施工机械化进程不断地发展,将来一段时间凿岩台车钻爆替代风钻钻爆 施工是未来地下工程开挖的发展方向之一。     

基于CFD方法的空调风管除霜性能开发

基于空调风管除霜性能开发过程,将总体性能分解到风管性能、玻璃近壁面的速度性能以及考虑温度的除霜性能。使用计算流体力学(CFD)方法,在设计前期通过稳态分析控制风管的性能及速度性能;在设计后期通过瞬态分析评估空调除霜的能力。分析结果表明,空调除霜性能目标从部件到整车均满足要求。     

盾构法联络通道密封垫设计及防水试验研究

为探究适合盾构法联络通道工程的密封垫断面形式,以宁波市轨道交通3号线第1条盾构法联络通道为工程背景,针对遇水膨胀橡胶设计阴阳凹凸、圆形孔洞、梳形、矩形等4类断面。对各断面形式进行可行性分析,选取阴阳凹凸断面与矩形断面作为初选方案。利用Abaqus/Explicit计算模块对2种断面的接触应力进行有限元分析,通过设计“一”字缝耐水压力试验,验证数值模拟中接触应力较大的矩形断面的防水能力。研究表明： 1）数值模拟结果显示,接触面最大接触应力与平均接触应力均随着张开量的增加而减小; 同等张开量与错台量下,在压缩与膨胀2个阶段中,矩形断面的接触应力均大于阴阳凹凸断面,因此选取矩形断面作为备选方案。2）“一”字缝耐水压力试验结果表明,矩形断面密封垫保压48 h后耐水压力明显提升,且张开量越大耐水压力提升幅度越大。3）综合数值模拟与试验结果可知,该矩形断面密封垫满足0.6 MPa的防水要求。     

On Safety in Dismantling Temporary Strut of Super-large Tunnels with Double-layer Primary Support北大核心CSCD

More and more multiple-track tunnels and super-large section tunnels have been built, and disman- tling of temporary strut is a weak point of the whole structure during force transfer when the secondary lining is con- structed. It is significant to guarantee structure safety during dismantling of temporary strut. Little systematic re- search on safety in dismantling of temporary strut of the super-large section tunnel with double-layer primary support has been conducted, so the internal force and security of the two-layer primary support of the Xinkaotang tunnel were analyzed by a numerical analysis and site measurement, and it proves the effect of two-layer primary support on the safety during strut dismantling. The research results indicate that: (1) with constant support thickness and one-time longitudinal dismantling length, the safety factor of secondary primary support is larger than that of the first primary support, and the safety factor of the first primary support is larger than that of the single-layer primary support. Change range of safety factor for the first primary support is smaller than that of the single-layer primary support, and the safe factor for the single-layer primary support is smaller than that of the secondary primary support; (2) with the same support pattern, the safety factors increase firstly and then decrease with an increase of the onetime dismantling length. The calculated results of various cases show that the reasonable one-time dismantling length for this project is about 9 m. © 2018, Editorial Office of "Modern Tunnelling Technology". All right reserved.     

Effect of Explosion in a Gas Pipeline Compartment of a Utility Tunnel on Neighboring Metro Tunnels北大核心CSCD

In this paper the numerical simulation analysis of the effect of explosion in the gas pipeline compartment of a utility tunnel on neighboring metro tunnels was conducted using the software AUTODYN. The results show that the TNT equivalent in a fireproof partition with length of 200 m is 41.6 kg when the gas concentration in the gas pipeline compartment reaches 10%; the blast wave has much effect on the crown and arch waist of the round metro tunnel and it’s necessary to take some protective measures in both areas; when the surrounding soil is sand, the utili- ty tunnel is above the round metro tunnel and their alignments are in the same direction, the greater the vertical spacing between the utility tunnel and the metro tunnel, the smaller the effect of the blast wave on the metro tunnel; when the vertical spacing is 7.2 m, the maximum dynamic tensile stress is 1.86 MPa (including the static stress value of 1 MPa in the tunnel segment) and it is slightly smaller than the designed tensile strength of metro tunnel (about 1.89 MPa). The maximum vibration velocity and the maximum displacement meet the structural stability require- ments, so it is suggested the vertical spacing between the utility tunnel and metro tunnel shall not be less than 7.2 m. © 2018, Editorial Office of "Modern Tunnelling Technology". All right reserved.     

A Study of Prevention Techniques for Tunnel Lining Defects北大核心CSCD

Defects of tunnel lining, such as inadequate thickness, voids, cracks, rock falling and water leakage etc., endanger the safety of railway tunnel operation. Based on the site construction, an analysis of the reasons for lining defects was conducted; technical measures against lining defects were proposed and tests were carried out at site. The results show that these measures are reliable and effective, and the purposes of prevention and treatment are re⁃ alized. © 2018, Editorial Office of "Modern Tunnelling Technology". All right reserved.     

基于PMS理论的常规潜艇任务可靠性研究

针对常规潜艇功能复杂、任务多变的特点,将多阶段任务系统(phased mission system,PMS)理论引入到其任务可靠性的分析中.深入分析常规潜艇的鱼雷攻击任务,建立任务可靠性模型,用马尔可夫过程法进行了任务可靠度计算,为常规潜艇任务可靠性模型的建立提供一种新方法.     

南京地铁乘客刷卡特征分析

乘客出行矩阵指乘客在地铁起点车站和终点车站间乘坐路径的汇总,是交通规划及运营管理的重要基础数据。利用南京地铁AFC系统中一卡通交易记录建立乘坐路径矩阵,以本站进出这一行为作为切入点,统计一周之内本站进出发生的次数、逗留时间等指标,从行为学上对其进行深入分析,并将其分为主观故意和客观被迫两种,分别提出应对措施,为地铁运营管理及票务政策制定提供依据。