Analysis of blast wave propagation inside tunnel

The explosion inside tunnel would generate blast wave which transmits through the longitudinal tunnel. Because of the close-in effects of the tunnel and the reflection by the confining tunnel structure, blast wave propagation inside tunnel is distinguished from that in air. When the explosion happens inside tunnel, the overpressure peak is higher than that of explosion happening in air. The continuance time of the blast wave also becomes longer. With the help of the numerical simulation finite element software LS-DYNA, a three-dimensional nonlinear dynamic simulation analysis for an explosion experiment inside tunnel was carried out. LS-DYNA is a fully integrated analysis program specifically designed for nonlinear dynamics and large strain problems. Compared with the experimental results, the simulation results have made the material parameters of numerical simulation model available. By using the model and the same material parameters, many results were adopted by calculating the model under different TNT explosion dynamites. Then the method of dimensional analysis was used for the simulation results. As overpressures of the explosion blast wave are the governing factor in the tunnel responses, a formula for the explosion blast wave over-pressure at a certain distance from the detonation center point inside the tunnel was derived by using the dimensional analysis theory. By comparing the results computed by the formula with experimental results which were obtained before, the formula was proved to be very applicable at some instance. The research may be helpful to estimate rapidly the effect of internal explosion of tunnel on the structure.     

Test and Analysis of an Existing Tunnel Vibration Induced by Blasting Construction of Diaphragm Wall

According to the blasting construction of the diaphragm wall of Puxi approaching section of East Fuxing Road river-crossing tunnel,the monitoring project of the vibration of the existing tunnel induced by the blasting construction is put forward,which includes the sensors' location,monitor method and the vibration monitoring system.Based on the monitoring data of the explosion vibration,the vibration wave forms,velocities,acceleration responses,main frequencies and fields of measure points are analyzed under the conditions of three locations and different charge quantities.According to the safety-judging standard of explosion vibration,the conclusion that the existing tunnel is safe under the explosion vibration is then drawn.Furthermore,the spectrum characteristics of three explosion vibrations and the spectrum changing properties of explosion vibration wave transmitting in different directions are concluded,which can provide reference to similar projects.     

初探石墨薄膜的表面结构及导电性

论述了在常温下和在大气状态下,扫描隧道显微镜（STM）在石墨薄膜表面上的电场加工实验,并对作用机理进行了分析,认为表面结构现象生成是场蒸发效应作用的结果,其导电性受外电场力的大小和薄膜层数之间的束缚力的影响。     

衬砌台车关键受力部位的确定及强度计算

通过对大断面整体钢模衬砌台车在实际使用中受力情况的分析,提出衬砌台车实用的强度设计计算要点,据此方法设计的产品应用于特大断面隧道衬砌施工中,成功地避免了变形、压坍、跑模等事故,有明显的比较优势。     

顶板瓦斯巷在145采面（二采3#层俯二采煤面）的应用

城子河矿立井145综采队现回采3#层俯采二面,该面属高瓦斯工作面,在回采过程中最高瓦斯涌出量达49.5m3/min。在回采一面时采用了尾排巷排放瓦斯及上巷风排方法治理瓦斯,这种方法配风量大,上转角及回风巷经常超限;在回采二面时采用了顶板瓦斯巷排放瓦斯,经过实践,证明这种方法是可行的、安全的、合理的,经济效果显著。     

IPv6隧道服务的设计与实现

隧道技术为I pv6在现有的广泛分布的I pv4网络上提供了虚拟链路,为I pv4网络向I pv6网络的过渡方案之一,可以保证I pv4能够平稳过渡到I pv6;除此之外,该技术还可以对普通用户做到"无缝",对信息传递做到高效、便捷。本文将讨论校园网中I pv6隧道的设计与具体的实现。     

膨胀型地层修建大断面隧道病理防治技术

文中就膨胀型复杂地层中隧道施工出现的塌方和衬砌受压变形破坏现象,介绍了施工应采取的技术措施和病理预防及治理技术。     

超导与诺贝尔奖

介绍超导研究方面获得诺贝尔奖的几个项目,并简介了超导的应用.     

超高层酒店结构设计中难点探讨

超高层酒店在结构设计中涉及到诸多难题，本文结合无锡某超高层酒店的结构，着重对基础大体积混凝土、风洞试验、高位转换的处理以及加强层的设置等进行了探讨。     

超前管棚在隧道工程中的应用研究

超前管棚支护是隧道施工中穿越软弱破碎围岩的一种有效的预支护方法。介绍超前管棚的受力原理与模型、设计与施工要点及适用范围等,并结合工程实例,论证超前管棚技术在隧道施工中的应用价值。