全断面隧道掘进机施工方法探讨

隧道的全断面施工方法主要有钻爆法、全断面隧道掘进机施工法和混合法施工等三种。一般情况下,隧道所处环境及所穿过的地质条件都很复杂,因此就其施工方法的选用而言,目前尚没有统一的标准。通过对国内外隧道(洞)工程施工实例的总结,全面分析了影响隧道施工方法选择的因素及应采取的相应措施。结合隧道用途及所需隧道的几何形状和尺寸,建立了隧道施工断面和所需隧道断面的数学模型,通过对此数学模型的求解,比较了全断面隧道掘进机施工和钻爆法施工的各自特点,在此基础上给出了根据所需隧道几何形状及尺寸应考虑的施工方法。文中还对这些施工方法的特点、应用范围、影响因素等内容进行了初步探讨,以期有助于我国隧道施工技术水平的提高。     

Half tunnels along hill roads of Himalaya—an innovative approach

‘Half tunnels,’ which are excavated as overhangs within steep slopes of hard rocks, have an advantage over conventional full tunnels or open excavations in that they involve less cost and time. However, due to a lack of interest and their uncommon occurrence, the design and analysis of half tunnels have remained by and large unexplored. In the present paper, an effort has been made to study some of the half tunnels in the Middle and the Higher Himalaya in India. In addition to studying the geology of half tunnels, rock mass properties pertaining to Q and RMR for the rocks exposed around the half tunnel have been evaluated. The Markland test has been carried out to assess the probability of plane or wedge failures along the slopes in the half tunnel area. The results obtained have been again confirmed by analyzing the data with the help of a computer program . Both analyses suggest that the wedges are stable and that all the half tunnels analyzed are safe. Finite element analyses for different slopes and spans of half tunnels have been carried out to study the distribution of stresses around half tunnels. The range of maximum tensile stress concentration in the roof of half tunnels for different slopes is suggested.     

Wind-tunnel development and trends in applications to civil engineering

A review is presented on wind tunnels capable of simulating natural winds, the boundary-layer wind tunnel (BLWT), and trends in their extensive use in civil-engineering practice. BLWTs and data-acquisition systems, as they evolved to meet needs in civil engineering, are described. Advancements are highlighted for the types of wind-load information now available to structural engineers and architects by BLWT tests using the advanced data-acquisition systems-the high-frequency base balance (H-FBB) and the synchronous multi-pressure sensing system (SM-PSS). Trends in applications of BLWT tests to determine wind effects on structures and to investigate wind-related environmental problems are described. Technical details of the BLWT, the H-FBB, the SM-PSS, and their proper use are available in references cited and are not restated in this review.     

矿井巷道风门降阻技术研究

根据传统风门存在的不足,应用力学内力平衡理论,提出一种新型低阻风门结构原理,将风门受到的风力相互抵消,使得开门阻力降低到最小.经过井下试用,证明低阻风门使用效果良好,解决了矿井风门开启难的问题.该原理可以用到其他类似的领域.     

临近基坑施工对地铁隧道影响的数值模拟分析

基坑开挖卸荷必然对临近软土地铁隧道产生影响,因此如何预测隧道变形并提出相应预防和保护措施显得尤为重要。结合上海地区一个临近地铁隧道的基坑工程,运用整体有限元分析方法对地铁隧道在基坑施工过程中所产生的影响进行弹塑性分析。分析结果与工程实测数据比较吻合,表明整体有限元方法可以较好地模拟此类工程问题,从而为实际工程的设计施工提供一定的理论和计算依据。     

Analytical solution to rock pressure acting on three shallow tunnels subjected to unsymmetrical loads

According to the interaction of three shallow tunnels with large section, the analytical solution to rock pressure has been derived and discussed. The load model is given when the bilateral tunnels are excavated. According to the model, the stresses of three tunnels and single tunnel are calculated and compared to analyze the distribution characteristics, where the stresses are influenced by controlling factors of clear distance, covering depth and inclination angle of ground surface. The results show that, in general, the bias distribution is more serious. Therefore, it is significant to settle down the load model of three shallow tunnels so as to determine the measure of reinforcement and design the structure of support. The model and results can be used as a theoretical basis in designation and further research of the three shallow tunnels.     

城市交通隧道洞口污染物扩散的控制策略研究

通过大型环境风洞试验的方法,研究了绿化隔离带以及中隔墙对城市交通隧道洞口污染的扩散进行了研究.对于设置绿化隔离带工况,研究了不同风速大小/风向下绿化隔离带对废气的洞口直接排放中污染物扩散影响,获得了洞口排放污染物在不同来流风速/风向条件下的浓度衰减规律及其影响范围;对于设置中隔墙工况,试验涉及了三种不同中隔墙长度(隧道...     

Identification and analysis of Swiss National Road tunnels pathologies

In order to evaluate the general conditions (i.e. safety, serviceability and durability) of tunnels, a detailed analysis of the lining structure and surrounding rock mass is required. During the service life of the tunnel, regular survey activities should be performed to check the tunnel conditions and regular conservation practices are necessary to preserve the tunnel’s structural integrity and guarantee safety and serviceability during operation. The collection of data about tunnels since their construction and during their service life may help in the assessment of tunnel conditions and improve the understanding of tunnel degradation with time. The long term behaviour of the Swiss National Road tunnels has been studied and a specific data base has been developed. Based on detailed literature review and analysis of principal inspections results collected in the data base, the main pathologies that affect the Swiss road tunnels have been identified. In addition, by means of a specific data analysis, both degradation potential and rate have been investigated and the main influence factors involved have been selected. The obtained results confirm what was expected according to observations in the past. After a brief introduction about the tunnels of the National Roads network, this paper describes the main steps of the data analysis, different methods used and main results of the analysis. Due to the fact that the tunnels within Swiss National Roads were developed during the 60s, attention has been focused only on concrete lined tunnels.     

圆形隧道的粘弹性应力分析

本文讨论圆形隧道的粘弹性应力分析问题。文中给出了在隧道围岩自重作用下,衬砌与围岩均为粘弹性材料时,求解衬砌与围岩变形及内力的一般性解答。求解的方法是:将衬砌与围岩相互作用的径向力和切向力表示成三角级数,按弹性问题分别求解衬砌及围岩的变形和内力;然后利用粘弹性——弹性对应原理,由弹性解得到粘弹性问题的解;再利用衬砌与围岩间变形的协调条件,确定衬砌与围岩相互作用之径向力和切向力级数中的系数,进而求得衬砌及围岩内力和变形的粘弹性解。