Running Tunnels Research Articles

Application of Blow-Off Wind Tunnel Control Based on Genetic Algorithm Optimized BP-Neural Network PID Neural Network

For a blow-off tunnel running, there is the large delay and lag issues. We build a mathematical model of the wind tunnel Mach number control by the test modeling method, then analyse the pros and cons of various control methods based on BP neural network control algorithm. Put forward genetic algorithm optimization neural network adaptive control method to solve the large inertia of the wind tunnel system, and large delay. A large number of simulation studies, run a variety of operating conditions for the wind tunnel simulation proved that the improved adaptive neural network PID control method is reasonable and effective.

Application of Blow-off Wind Tunnel Control Based on Genetic Algorithm Optimized BP-Neural Network PID Neural Network

For a blow-off tunnel running, there is the large delay and lag issues. We build a mathematical model of the wind tunnel Mach number control by the test modeling method, then analyse the pros and cons of various control methods based on BP neural network control algorithm. Put forward genetic algorithm optimization neural network adaptive control method to solve the large inertia of the wind tunnel system, and large delay. A large number of simulation studies, run a variety of operating conditions for the wind tunnel simulation proved that the improved adaptive neural network PID control method is reasonable and effective.

Aerodynamic design for China new high-speed trains

The high-speed trains have very complex running environments, which contain single-train running in open air, two-trains passing by in open air, single-train running in tunnel and two-trains passing by in tunnel. As the environment wind appears, cross-wind effect must be considered. Aerodynamic design of high-speed trains mainly aims at the drag, lift, moment, impulse pressure waves, aerodynamic noise etc at typical running conditions. In the paper, the aerodynamic design processes of CRH380A and 380B are introduced and the aerodynamic performances of different designs are emphatically analyzed and compared. Wind tunnel experiments and running tests indicate that the new generation of high-speed trains holds excellent aerodynamic performances.

Improvement of Running Tunnel Based on OSPF TE

In the existing traffic engineering, information can only be transmitted in a single OSPF area. When there are multiple OSPF areas, the tunnel is difficult to establish. For this problem, combined with the existing OSPF technology on three categories LSA processing flow, in the right less impact on the relevant modules of the situation, solutions are proposed to achieve a particular area of traffic engineering information across the region spread to other regions in order to facilitate the establishment of range of the tunnel.

Control Standard of Ground Surface Settlement Induced by Running Tunnel Construction in Beijing Subway

Ground settlement, especially the ground surface settlement induced by subway tunneling is an important issue. However, there is no an agreed standard for controlling ground surface settlement during the subway construction at present. The control standard of ground surface settlement was studied using the methods of statistical analysis and numerical simulation based on the running tunnel in Beijing subway. According to the research results, a conclusion could be obtained that the ground surface settlement can be controlled within 40 mm using the general construction measures in Beijing subway running tunnel construction, and furthermore, the settlement of 40mm will not damage the existing nearby structures and utilities including neighboring buildings, bridges and pipelines, etc. So the control valve of 40 mm is rational, which can be adopted as the control standard of ground surface settlement induced by running tunnel construction in Beijing subway.

Necrosis of the long process of the incus following stapes surgery: New anatomical observations

The most frequent complication (generally recognized during revision procedures) following seemingly successful stapedotomies and stapedectomies is necrosis of the long process of the incus. This is currently ascribed to a malcrimped stapes prosthesis or to a compromised blood supply of the incus. The two-point fixation can cause a mucosal injury with a resulting toxic reaction, and also osteoclastic activity. An important aspect in the engineering of ideal stapes prostheses is that they should be fixed circularly to the long process of the incus with appropriate strength. The objective of this study was to compare current knowledge relating to the blood supply of the ossicular chain with the present authors' observations on cadaver incudes. Most of the papers dealing with this issue appeared in the mid-20th century. The published data were compared with the authors' findings gained from photodocumentation on 100 cadaver incudes. The photos were taken with a Canon EOS 20 digital camera (Canon, Inc., Lake Success, NY) with a 5:1 macro-objective. The long processes of the incudes were examined from four directions under a Leica surface-analyzing microscope (Leica Microsystems GmbH, Wetzlar, Germany). Analysis of the positions of the entrances of the feeding arteries (nutritive foramina) on the incudes revealed 1-4 nutritive foramina on the long processes of 48% (24) of the left-sided incudes and 56% (28) of the right-sided incudes. The positions of these foramina differed, however, from those previously described in the literature. They were mostly located not on the medial side of the incus body or on the short process or on the cranial third of the long processes, but antero-medially, mostly on the middle or cranial third. In 48% of all the incudes examined, an obvious foramen was not observed either in the body or in the long process of the incus. No relationship was discerned between the chronological age of the incus specimens and the numbers and/or locations of the nutritive foramina. In each case, the opening of the foramen was the beginning of a tunnel running obliquely and medially upward through the corticalis of the long process of the incus. The foramina are thought to be capable of ensuring a richer blood supply between the surface and the inside of the long process, allowing the arteries to run in and out. These observations indicate that conclusions drawn from classical anatomical works appear to need reconsideration. The present authors consider that the reason for the necrosis of the long process of the incus is not a compromised blood supply, except in some exceptional anatomical situations. They discuss the possible reasons why malcrimping may lead to necrosis of the long process of the incus. To prevent such malcrimping, attention is paid to the new generation of prostheses.

Rebound effects of running tunnels underneath an excavation

To maximize the usage of underground space, there will be more and more engineering projects that will be built above the running tunnels. To ensure the safety operation of the running tunnels, there is a need to predict and control the tunnel deformations. This paper combines the experiences from the construction of underpasses above running tunnels in the soft soil region of Shanghai and discusses the rules of rebound effects of running tunnels due to excavation by FEM numerical simulation. The writer attempts to use the soil unloading Semi-experiential modulus derived from the Shanghai soft soil region experiments, taking into consideration the effects of the load-space relation and the effects of the property of the soil within the rebound zone in reaction to the unload distribution to propose a calculation formula for the rebound effects of running tunnels. The results calculated from the formula are very close to those measured, hence proving that the formula is a simple and practical way to predict tunnel deformations within the same regional projects. (A) This paper was presented at Safety in the underground space - Proceedings of the ITA-AITES 2006 World Tunnel Congress and the 32nd ITA General Assembly, Seoul, Korea, 22-27 April 2006. For the covering abstract see ITRD E129148. Reprinted with permission from Elsevier.

Bridge construction above existing underground railway tunnels – A case study from Cheong-Gye Cheon restoration project

A river restoration work named 'Cheong-gye Cheon Restoration Project' launched in July 2003 in Seoul, Korea. The project includes construction of 21 new bridges. Four bridges among them were planned above running tunnels which are about 10m below ground surface, and of which axis is parallel to bridge axis. All bridges were for heavy vehicle traffic. The subway tunnels were constructed by the sprayed concrete lining method (SCL), i.e., NATM, in between 1983 and 1995. In design phase several measures to reduce the impact of bridge loads on the railway tunnels were considered. It was required to design bridge abutments to avoid eccentric loads on the tunnel and reduce stresses causing any structural harm to the running tunnels. Balance of construction loads was the main issue during construction. Two different foundation methods were employed: piled-foundation and grouted-foundation. To evaluate the behaviour of ground and tunnel, three dimensional numerical modelling was performed using the computer program MIDAS/GTS. Construction management program including intensive instrumentation of the running tunnels was implemented to secure safe construction. The bridges were successfully completed without damages to the running tunnels. Design analysis, instrumentation and construction performance are presented and reviewed in this paper. It is found that the piled-foundation is beneficial in reducing the impact of the bridge load, meanwhile the grouted-foundation is more cost-effective. (A) This paper was presented at Safety in the underground space - Proceedings of the ITA-AITES 2006 World Tunnel Congress and the 32nd ITA General Assembly, Seoul, Korea, 22-27 April 2006. For the covering abstract see ITRD E129148. Reprinted with permission from Elsevier.

Marmaray project: Tunnels and stations in BC contract

Abstract Istanbul is one of the most famous historical cities in the world. However, the project alignment selected as the best of a range of alignments cannot avoid passing beneath the historical and cultural heritages of Istanbul as well as under ancient and densely inhabited areas of the city. This paper will explain some of the challenges related to the bored tunnels. Historical buildings are vulnerable. Yet many existing residential and office buildings are old and constructed on minimal foundations. As a consequence, it is vital that any drawdown of groundwater and any ground settlements have to be minimized. In addition, the connection between the immersed and bored tunnels will be made directly and totally underground, without the usual intermediate shafts and beneath the deep waters of the Bosphorus Strait. This operation needs the utmost control of the tunnel excavation face to ensure its stability and to minimize water ingress. Based on such considerations, tunnel excavation by tunnel boring machine (TBM) using a slurry shield and having the ability to operate under high pore pressures was recommended as the method of excavation for the main running tunnels. The paper will explain how the design team from Avrasyaconsult – the Employer’s Representative – arrived at the final minimum, specific and functional requirements of the bored tunneling works which are to be carried out using the ‘FIDIC EPC/Turnkey Project’ conditions.

Design and Testing of a Transonic Linear Cascade Tunnel With Optimized Slotted Walls

In linear cascade wind tunnel tests, a high level of pitchwise periodicity is desirable to reproduce the azimuthal periodicity in the stage of an axial compressor or turbine. Transonic tests in a cascade wind tunnel with open jet boundaries have been shown to suffer from spurious waves, reflected at the jet boundary, that compromise the flow periodicity in pitch. This problem can be tackled by placing at this boundary a slotted tailboard with a specific wall void ratio s and pitch angle α. The optimal value of the s-α pair depends on the test section geometry and on the tunnel running conditions. An inviscid two-dimensional numerical method has been developed to predict transonic linear cascade flows, with and without a tailboard, and quantify the nonperiodicity in the discharge. This method includes a new computational boundary condition to model the effects of the tailboard slots on the cascade interior flow. This method has been applied to a six-blade turbine nozzle cascade, transonically tested at the University of Leicester. The numerical results identified a specific slotted tailboard geometry, able to minimize the spurious reflected waves and regain some pitchwise flow periodicity. The wind tunnel open jet test section was redesigned accordingly. Pressure measurements at the cascade outlet and synchronous spark schlieren visualization of the test section, with and without the optimized slotted tailboard, have confirmed the gain in pitchwise periodicity predicted by the numerical model.

Sea-surface wave growth under extraterrestrial atmospheres: Preliminary wind tunnel experiments with application to Mars and Titan

We describe for the first time the generation and measurement of capillary waves in a water surface in a wind tunnel running with air at pressures of 15–1000 mbar. These experiments suggest a stronger dependence of wave generation on atmospheric density than the simple proportionality that might be expected from energy transfer arguments. Additionally, airflow over a nonaqueous fluid (kerosene) was found to produce waves of higher amplitude than for water under the same conditions. These preliminary results may indicate different efficiencies of wave generation on other planets, for which empirical terrestrial relations therefore do not apply, and thus may have a bearing on the lack of strong shoreline features on Mars and the possibility of specular glints from hydrocarbon lakes on Titan.

Metro de Santiago: tunnelling under the Fray Andresito Bridge

The northern extension of the Line 2 of the Metro de Santiago, with approximately 1.6 km total length. Running tunnels consist of double-track single-tubes. At the southern route section, tunnel horizontal alignment bents with a 253 m radius to link to the existing Cal y Canto station. This constraint causes the tunnel to pass a few centimeters below the heavily loaded abutment foundation of the Fray Andresito bridge just before reaching the Mapocho River. To make possible the construction of this tunnel section, special construction and monitoring measures were required, as explained next. The bridge foundation was underpinned by six piles, constructed manually from within small-dimension pilot tunnels, excavated in advance of the main tunnel. Piles were provided with an active jacking and monitoring system to control load distribution and deformations during main tunnel excavation. Jacks were accommodated in the interior of a rectangular steel frame installed within the body of each pile and were accessible during the whole construction period. Main tunnel excavation was carried out with the use of mined tunneling methods (NATM). This comprised a sequential tunnel excavation, followed by the installation of a temporary reinforced shotcrete lining. The cross-section was subdivided in three independent partial headings. Side drifts were excavated in advance of the central heading. When deformations stabilized, the jacking system was removed for the installation of the permanent tunnel secondary lining. Structural and serviceability requirements were provided by the installation of a massive reinforced concrete cast in place secondary lining, with thickness ranging from 1 to up to 2 m. This lining was installed before underpinning piles were demolished. After the secondary lining was installed and achieved sufficient resistance, the exposed parts of the underpinning piles were demolished, transferring the total load of the ground and bridge foundation to the tunnel lining. Additionally to the typical control of ground and tunnel deformations, monitoring also included the screening and control of jack loads (pressure cells), total and relative deformations of piles and steel structures (transducer bars and a rotational laser system). At all times, monitoring data fed continuously an interpretation software designed specifically for this project, which compared registered values with pre-established trigger levels. Construction of this section was complete successfully with maximum registered deformations in the order of only 5 mm, as required by the client and foreseen by the designers. Results achieved by the use of the methods and additional measures carried out, showed the accomplishment of both design and construction purposes, allowing the construction of this metro line across a particularly complex section with a high level of concern on the impact of construction works on the surrounding urban environment. (A). Reprinted with permission from Elsevier. For the covering abstract see ITRD E124500.

A subsurface “drift and pile” protection scheme for the construction of a shallow metro tunnel

In the construction of a shallow running-tunnel for Beijing metro line No. 13, due to restrictions by the surface environment of the area, a subsurface protection scheme was applied: two small cross-section drifts with shotcrete linings were constructed at above each side of the subway running tunnel, and reinforced concrete piles were installed into the ground from within the drifts. The piles were rigidly connected with the floor slabs of the drift linings, so that the drifts could effectively help extend the height of the protected zone of ground. With no disturbance to the normal living of the residents in the area, the major objective of the scheme was to separate the negative effects of tunneling on two nearby high-rise residential buildings, one at each side of the tunnel, respectively. Relating to the scheme, this paper presents the relevant site conditions, design concepts and analyses, constructions and monitoring highlights.

The Channel Tunnel Safety Authority

The paper is a critical review of the operation of the Channel Tunnel Safety Authority (CTSA) before and since the inauguration of the tunnel system. It considers four of its major decisions in relation to the tunnel fire hazard: (1) spacing of the cross-passages that link the running tunnels to the service tunnel and form the escape routes for people caught in a fire; (2) construction of shuttle carrier wagons for heavy goods vehicles involved in the severe tunnel fire of November 1996; (3) non-segregation of car drivers and passengers from their vehicles; and (4) requisitioning a Safety Case. It concludes that CTSA's decisions resulted in reduced safety in spacing and construction in (1) and (2), respectively, a lengthy theoretical and experimental study that followed a preconceived, rather than preceded a sought, solution in (3) and a Safety Case that followed rather than preceded construction. In all four examples an alternative decision in the direction of greater safety could have led to severe economic consequences for the tunnel project.

The North Hollywood Project, Los Angeles

The North Hollywood Project is a 10 km twin tunnel extension to the Los Angeles Metro Red Line valued at US$1·3 billion. The extension includes three stations constructed by cut and cover methods, together with the rail track, the necessary support systems, and rolling stock. This paper covers the main civil engineering construction of the project. The construction of the cut and cover stations is described. A number of interesting features of the tunnel construction are described, including the boring of the main running tunnels using tunnel boring machines (TBMs), the construction of a special seismic section of oversize tunnel through a major fault using shotcrete lining, track level rooms, starter tunnels and cross passages between running tunnels. An important emphasis of the paper is on the rock tunnels driven by the TBMs. The difficulties caused by severe geological conditions include dealing with water at high pressure and fissure grouting to reduce water inflow through the permanent lining. Both the temporary and the permanent tunnel lining are described.

Anterior cruciate ligament reconstruction with alternative tibial tunnel: early results after accelerated weight-bearing.

In this study an autologous graft of 50%-60% of the patellar tendon (mid portion) was used for anterior cruciate ligament (ACL) reconstruction in 50 patients (19 women, 31 men; mean age 26 years). The distal part of the graft was fixed in a tunnel running from the centre of the anatomical tibial attachment of the ACL to the place where the bone block of the graft was removed from the tibial tubercle. A rehabilitation programme with accelerated weight-bearing postoperatively without external protection was followed. Evaluation consisting of function and stability tests, activity level and Lysholm's subjective function score took place an average of 26 months postoperatively; 35 of 50 patients had an additional evaluation monthly for 1 year and 6 monthly after 1 year. The stability tested manually after an average of 26 months postoperatively was good in 45 patients; 5 of them had a positive Pivot shift test (one 1+, two 2+, two 3+). Only 2 of these patients complained of giving way of the knee. All patients regained good knee function. The average postoperative Lysholm score was 85 (SD 14.5) and the subjective stability of the knee was described as 'good' in 41 patients, and 'poor' in 9. The objective stability was good in 7 of these 9 patients. The mean Tegner score was 6.5 (SD 1.9). The mean time to resuming activities was 5.4 weeks for full weight-bearing, 10 weeks for running, 13.5 weeks for going back to work and 6 months for returning to previous sports. In the group of 35 patients who underwent an additional evaluation, no change in manual stability was found during observation except for 3 of them. No patellar ruptures were seen. The operation technique used in this study appears to allow accelerated knee rehabilitation after ACL reconstruction.

TUNNEL COOLING, DRAINAGE AND FIRE-FIGHTING.

This paper describes the three main pipework systems in the Channel Tunnel. These systems have more than 350km of main pipes, and provide for cooling, drainage, and fire-fighting services. Each system operates automatically, and can be controlled remotely, as required. As far as possible, the drainage and fire-fighting systems are both based in the service tunnel or at locations easily accessed from it. This permits maximum maintenance access, without disruption of train services. Both these systems have built-in redundancy to provide high reliability. The cooling system is unusual for a tunnel. In the case of the Channel Tunnel, it is required because of the unprecedented levels of power, needed to overcome shuttle aerodynamic resistance to movement within the tunnel, and the high forecast traffic levels. A new form of cooling system was developed, which circulates chilled water in the running tunnels, and provides heat exchange across a continuous bare pipe surface for friction energy and other losses, rejected as waste heat to the tunnel air. The cooling pipes need almost no maintenance. For the covering abstract see IRRD 877203.

TUNNEL VENTILATION, INCLUDING AERODYNAMICS.

Keywords TRANSMANCHE LINK JV CHANNEL TUNNEL, TUNNELS, VENTILATION, AERODYNAMICS, PROPERTIES, SHUTTLES, TRAINS, DESIGN, AIR, VELOCITY, SIMULATION, PISTONS, SYSTEMS, FANS, RELIEF, DUCTS, DAMPERS, CROSSOVERS, DOORS, OPERATION CHANNEL TUNNEL UK, FRANCE... Show All

TUNNELS - SPECIAL WORKS.

Keywords GIE TRANSMANCHE CONSTRUCTION TUNNELS, CHANNEL TUNNEL, WORKS, PASSAGES, TRANSVERSE, PUMPING STATIONS, RAILWAYS, CROSSOVERS, SPECIAL, PISTONS, RELIEF, DUCTS, AIR, VENTILATION, DEWATERING, DESIGN, STRUCTURES, CYLINDRICAL, CONSTRUCTION, ELECTRICAL, EQUIPMENT, ROOMS, LININGS, EXCAVATIONS, SHAFTS, SERVICE, RUNNING, STAGES, METHODS, GALLERIES, CORES, EXCAVATING, TUNNELLING CHANNEL TUNNEL FRANCE... Show All

TUNNELS - SHAFT AND MARSHALLING CHAMBERS.

Keywords GIE TRANSMANCHE CONSTRUCTION TUNNELS, CHANNEL TUNNEL, CHAMBERS, SHAFTS, MARSHALLING, TEMPORARY, STRUCTURES, DRIVING, TUNNELLING, WORKS, PERMANENT, VENTILATION, PUMPING, EQUIPMENT, CONSTRUCTION, METHODS, TBM, BORING, MACHINERY, ASSEMBLY, CROWNS, HEADINGS CHANNEL TUNNEL FRANCE... Show All