ITA study of non-destructive methods of inspecting and testing tunnel linings

The International Tunneling Association's Working Group on Maintenance and Repair of Underground Structures is preparing a report dealing with non-destructive methods of inspecting and testing tunnel linings. This request for information details the scope of the group's work and the types of information the group is seeking at this time.     

Access way to underground space: Present status of access ways to underground space with examples of spatial requirements ITA Working Group 4 “subsurface planning”

This report presents the results and output from a questionnaire undertaken by the ITA Working Group No. 4 regarding “Design Criteria for Access ways” to different types of underground structures. This theme was considered an important issue as the design and layout of access ways and installed mechanical equipment have great influence on construct ability and construction costs, maintenance and operation of the underground structures.

The questions raised were basically dealing with the theme of access ways, but as well with the wider scope of design criteria for underground structures, such as: road (transport) tunnels; underground (metro) railway stations; underground parking areas and underground shopping malls and other facilities.

Foreword

The theme of this report, design criteria for access ways to underground structures, was proposed by the representatives of Japan and Spain during the ITA Working Group No. 4 meeting, held in Sao Paulo in 1998. Around the globe an increased application of underground space has been experienced and the design of access ways is an important aspect of underground structures. The participants in the meeting in Sao Paolo, representing their member nations, supported the theme. Following the Working Group meetings in Oslo (1999) and Durban (2000) a questionnaire was prepared by Japan and Spain and distributed amongst the ITA member nations. The questions raised were basically dealing with the theme of access ways, but dealt as well with the wider scope of design criteria for underground structures, such as: road (transport) tunnels; underground (metro) railway stations; underground parking areas and underground shopping malls and other facilities.

The main intention of the Working Group No. 4 Subsurface Planning was that the findings of the questions raised could be of great help in the field of assisting, developing and harmonizing subsurface planning.

Not surprisingly, the member nations who replied to the questionnaires addressed the various aspects of this topic in different ways. Nevertheless, the diverse views clearly show differences in opinions and details by which various countries approach these issues. The report is intended to aid subsurface planners who wish to gain a broad view on how matters are dealt with in other countries or seek guidance in comparable situations – and also for the benefit and understanding of owners and operators of such facilities.

The fire and life safety issues in road and railway tunnels are of course of great importance for public confidence in such structures. These issues have been specifically dealt with in a previous report by Working Group No. 4; “Fire and Life Safety for Underground Facilities” published in the journal “Tunneling and Underground Space Technology” (TUST), volume 13/3 July/September 1998.

The ITA expresses the appreciation to the member nations who made contributions and especially to Japan who assembled and presented the material. The ITA also wish to thank Norway and the Netherlands for assisting in finalizing the report, which was completed under remaining Working Group 4 responsibilities.     

隧道工程无损检测技术理论与方法研究

本文介绍了隧道工程中锚杆、喷射混凝土和衬砌质量无损检测技术,为既有工程的加固改造质量评估和新建工程施工过程质量控制、验收、质量事故处理和后期维护使用,提供检测技术理论与方法。     

隧道工程无损检测技术理论与方法研究

本文介绍了隧道工程中锚杆、喷射混凝土和衬砌质量无损检测技术,为既有工程的加固改造质量评估和新建工程施工过程质量控制、验收、质量事故处理和后期维护使用,提供检测技术理论与方法.     

隧道及地下工程岩体模型材料研究现状分析

归纳了当今国内外地质力学模型相似材料的研究现状,指出了常用相似材料的优缺点,并对测试相似材料力学特性的方法作了介绍,最终选取相似程度最好的模型材料,以更好的模拟实际条件。     

Development of methods for the protection of buildings, structures, and underground utilities

Methods of protecting an urban setting during underground construction and underworking of lands are analyzed in an example of the development of domestic regulatory-recommendatory documents. Attention is focused on methods used to protect underground utilities. The urgency of accumulated experience is assessed for modern conditions of underground construction. The paper is based on results of analysis of the problem’s status, which was conducted for the development of Standard [1]. __________ Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 3, pp. 18–22, May–June, 2008.     

西南某水电站地下厂房顶拱衬砌裂损机理探讨

通过对水电站地下厂房顶拱衬砌裂损进行分析探讨,揭示了衬砌裂损的机理,并指出开挖过程中,顺层岩体的顺层滑移产生偏压是主要原因,提出了初步的修复措施,以提高地下厂房围岩岩层的抗弯刚度及强度。     

高层建筑施工对邻近地下隧道影响的监测分析

针对高层建筑对临近建筑的不利影响,结合具体工程实例,以此次安全监控的实施情况为依据,系统地说明了量测方法、数据处理以及数据的应用,并论述了对类似工程的指导意义.     

深埋长大隧道交叉段衬砌裂缝成因分析与处治

通过对某高速公路深埋隧道主、横洞交叉段开洞侧主洞衬砌裂缝的现场检测及性状分析,研究对比了可能引起衬砌开裂的各种因素,得出了开裂的主要原因,认为隧道交叉段地层工程地质情况复杂,构造应力在应力场构成中占有很大比例,水平应力要比竖向应力大,且在横洞开挖后。主洞开洞侧截面承载能力一定程度上有所削弱,衬砌受力不均匀,出现应力集中现象,从而导致混凝土开裂;基于现场地质参数及裂缝成因初步分析,利用有限元分析软件对衬砌开裂段的应力场及位移场进行了模拟,模拟结果验证了现场成因分析所得结论的正确性;基于现场裂缝实际情况,提出了详细的裂缝处治措施,可为今后解决类似隧道衬砌开裂问题提供参考。     

Fire and life safety for underground facilities: present status of fire and life safety principles related to underground facilities : ITA working group 4, “subsurface planning”

This study on the present status of fire and life safety principles for underground facilities is based on contributions by eight member nations of the International Tunnelling Association: Australia, Canada, China, Germany, Italy, Japan, Sweden and the U.SA This document may serve as a tentative guideline for future development in this field Findings are divided into three major category areas of underground works: road tunnels, railway tunnels, and underground parking facilities. Tables and explanatory information for each category are provided.     

基于结构材质状况的分层综合评定法在桥梁检测中的应用

以山东省枣庄市S343北留线漷河大桥为例,通过对桥面系及上、下部结构的病害进行了外观调查,分析了病害产生的原因,并通过混凝土强度、钢筋保护层厚度、混凝土碳化深度的检测对桥梁结构材质参数进行了测定,给出了各检测项的评定标度值,采用分层综合评定法确定了旧桥的技术状况等级,对桥梁的使用状态给出了科学评价,提出了后期维修养护建议,为桥梁后期养护、维修和加固提供了决策依据。     

Application of the comprehensive forecast system for water-bearing structures in a karst tunnel: a case study

Bulletin of Engineering Geology and the Environment - While tunneling in karst terrains, engineers may encounter unpredictable well-developed karst conduits, which frequently lead to water inrush...     

水下浅埋软岩隧道施作拱墙二衬力学效应的现场实测与分析

以一座用矿山法施工的水下浅埋软岩公路隧道为工程背景,基于现场实测数据,分析了施作拱墙二衬对初期支护受力性状的影响以及拱墙二衬本身的受力特性.研究结果表明:与浇注拱墙二衬混凝土的前一天相比,浇注完拱墙二衬混凝土后第20d,初期支护的局部锚杆轴力和局部型钢拱架应力明显减小,说明施作拱墙二衬能分担初期支护承受的部分围岩荷载;...     

Indicators for the evaluation of wind tunnel test section flow quality and application to a numerical closed-circuit wind tunnel

The flow in a wind tunnel test section must meet high standards to obtain accurate and reliable measurement data. Good flow quality demands a certain degree of spatial uniformity and temporal steadiness of velocity and pressure. In this paper, a set of six new indices is developed and presented that relate spatial aspects of the mean velocity field to flow quality. One index quantifies the degree of uniformity of the velocity field and can be used directly as a flow quality indicator. The five other indices are related to different types of deviations from spatially uniform flow; skewed flow and angularity (up-flow and down-flow, swirl, cross-flow, diverging and converging flow). The indices can be used to evaluate the flow quality in existing tunnels, to assess the impact of design modifications, as well as to carry out CFD-based design of new wind tunnels. As an example, the indices are applied to assess the impact of guide vanes and screens on the test section flow quality in a numerical closed-circuit wind tunnel.     

Proposal of a probabilistic model for multi-hazard risk assessment of structures in seismic zones subjected to blast for the limit state of collapse

It is desirable to verify the structural performance based on a multi-hazard approach, taking into account the critical actions the structure in question could be subjected to during its lifetime. This study presents a proposal for a probabilistic model for multi-hazard risk associated with the limit state of collapse for a reinforced concrete (RC) structure subjected to blast threats in the presence of seismic risk. The annual risk of structural collapse is calculated taking into account both the collapse caused by an earthquake event and the blast-induced progressive collapse. The blast fragility is calculated using a simulation procedure for generating possible blast configurations, and verifying the structural stability under gravity loading of the damaged structure, using a kinematic plastic limit analysis. As a case study, the blast and seismic fragilities of a generic four-storey RC building located in seismic zone are calculated and implemented in the framework of a multi-hazard procedure, leading to the evaluation of the annual risk of collapse.     

A comparison of two methods to project regional and state populations for the U.S.

This paper is a comparison of two contrasting methods for projecting population at the regional and state levels. A projection of the U.S. Bureau of the Census employs standard demographic methods, while the population projection by Data Resources, Inc., is based on economic opportunity. The methodological differences between these two projections are discussed, and the projections for the year 2000 are compared. While both projections use the same national control total for population in the year 2000, some of the regional and state projections are very different. The U.S. Bureau of the Census projects population decline in the Northeast and rapid growth in the West while Data Resources, Inc., projects some population growth in the Northeast and less rapid growth in the West.Funding for this project was provided by the U.S. Department of Energy under Contract W-31-109-Eng-38.The authors hope that this paper has illustrated the extent to which such a change in the growth pattern established in the 1970s may matter to the regions and states.     

ITA study of non-destructive methods of inspecting and testing tunnel linings

The International Tunneling Association's Working Group on Maintenance and Repair of Underground Structures is preparing a report dealing with non-destructive methods of inspecting and testing tunnel linings. This request for information details the scope of the group's work and the types of information the group is seeking at this time.     

Whole-stream phosphorus cycling: testing methods to assess the effect of saturation of sorption capacity on nutrient uptake length measurements

The cycling rate of nutrients such as phosphorus (P) is a fundamental parameter in stream ecology. In whole-stream ecosystem experiments, cycling rates are often assessed using continuous short-term nutrient addition studies. While several simplifying assumptions are generally recognised, these are rarely, if ever, fully tested under field conditions. One principal assumption is that uptake (sorption) processes do not become saturated during periods of nutrient addition, which is perhaps questionable from laboratory studies of soluble reactive phosphorus (SRP) sorption kinetics. Three approaches were developed and tested, which bridged the gap between laboratory-based net (sum of uptake and release) sorption kinetics and whole-stream assessments of P uptake. These were applied to a short-term (three times mean travel time of water in the studied reach) whole-stream multiple-rate P addition. The results were then tested independently with a whole-stream long-term (15 times mean travel time) SRP addition. The net sorption kinetics were not altered during the short-term addition with low SRP additions, 9-16 microg L(-1) (two to three times the ambient concentration). Although this may not be the case at higher added concentrations (as possibly hinted at five times the ambient concentration), the long-term addition showed no change in P uptake length with a P addition (39 microg L(-1)) 16 times higher than the ambient concentration.