Side Of Tunnel Research Articles

Mine-Tunnel Design & Monitoring Analysis for Major Faults and Complex Geological Conditions

Mining operations at Nanyang-Slope Coal Mine are considerably challenging. The Nanyang- Slope Coal Field has a complex tectonic structure; having major faults, large fissures and fracture- zones, and great changes in coal-seam thickness. Mine tunnel-way 301 traverses multiple complex faults with developed fractures, broken surrounding rock, and high tectonic stresses. The original rectangular-section tunnel design using anchor-bolt-mesh retainment was prone to rib-spalling, and the problem could not be controlled by use of additional encryption anchors on the tunnel sides. The mud-rock above the tunnel-ceiling is soft and argillized, which expands and softens on contact with water. This caused problems with the epoxy bonding agent failing to effectively secure bolt-anchors to the rock, resulting in anchor-bolt-mesh failure. In consideration of the complex geological conditions, a tunnel construction utilizing a curved wall arch-section and anchor-bolt- mesh-concrete spray was proposed. MJ-40 anchor-rod dynamometers were used to measure the forces in the tunnel rock-anchor bolts; and tunnel-rock deformation and surface displacement was monitored over the course of several weeks using a measuring station. Results show that the construction design effectively lowers the effects of the tectonic stresses on any one part of the tunnel, and demonstrates the safety and reliability of the tunnel-retainment and support design. DOI: http://dx.doi.org/10.11591/telkomnika.v11i3.2302

UNPREDICTABILITY KEY TO COLLISION AVOIDANCE

Life is one big obstacle course for a locust. Living in swarms in dense tree canopies, they not only have to avoid bumping into branches and other members of the locust mob, but they also have to steer clear of collisions with peckish predators. Avoiding all of these hurdles is no mean feat, as Fabrizio Gabbiani from the Baylor College of Medicine, USA, explains: ‘Suddenly something approaches and then you have to combine what you’re already doing, which is flying, with avoiding an object, which is quite a complex behaviour. And on top of that you can have wind gusts, so there are also [other] disturbances that could affect what you do.’ Gabbiani knew that locusts react in a stereotypical way when threatened with a head-on collision – which is more likely to occur with stationary objects – but wondered how they would cope with a side impact when a predator swoops in for the kill (p. 641).Suspecting that the locusts would also show stereotypical avoidance behaviour when presented with a side-on collision, Gabbiani and his post-doc Raymond Chan, headed out into the heat of the Texan sun to capture locusts in nearby shrublands to maintain their colony and begin their investigation.The duo tethered the locusts with a thread in a wind tunnel to prevent them from crashing against the walls as they flew freely, and used high-speed cameras to record the locusts’ movements. They then simulated a predator-like threat by projecting an image of an expanding square onto the side of the wind tunnel, and filmed how the insects reacted to this perceived incoming object. However, the locusts did not simply fly away from the approaching threat using a tightly choreographed suite of moves as expected. Gabbiani remarks, ‘We found something that is much more complicated; they actually seem to be going in all possible directions, even sometimes towards the approaching object,’ adding that, ‘In retrospect that makes sense; if you really want to be able to avoid a predator you want to be as unpredictable as possible.’To understand how the locusts were able to perform such an array of manoeuvres, the duo went back to the wind tunnel with their locusts to investigate the details of the insects’ evasive wing beats. This time a 2-cm-long thread restricted the locusts’ flight within a tiny sphere so that a camera could zoom in on their wings and film their movements at 500 frames s–1. However, restricting their freedom changed their escape tactics slightly: the team noticed that the insects interrupted their wing beats more often, allowing them to dive in response to the sideways threat. Gabbiani suspects that the insects may have some understanding that they are tethered. Nonetheless, the duo was also able to detect changes in the wings that also explained the range of collision-avoidance movements undertaken by the free-flying locusts. They found that increased height in the forewings and slight deformations in the curvature or tilt of the wings led to changes in the locusts’ body orientation and flight direction that would allow the insects to evade predators.Understanding how insects use their wings to fly is exciting and very useful as it may help us build better small flying robots, explains Gabbiani. These micro-fliers have great potential; for example, they could inspect burning buildings or aid rescue operations. However, to design appropriate robotic wings we need to better understand how minute deformations of the wing and split-second alterations in wing-beat patterns allow insects to duck and dive.

컨조인트 분석에 의한 터널 내 조명시설 설치조합별 경관 선호도 분석

PURPOSES : This study is to suggest suitable lighting facility installation plans by finding out driver's preference for combination of lighting facility installation among landscape factors that affect driver visibility in tunnels. METHODS : SD method is used to extract emotional factors that affect drivers' preference, Components of tunnel lighting facility installation are evaluated through conjoint analysis and it suggested relative importance of attributes and utility values. RESULTS : In the aspects of satisfaction levels of components of tunnel lighting facility installation, Tunnel side, two lows, and solid line arrangement type has the highest level of satisfaction. Extract emotional factors that affect drivers' preference are "safety", "openness" and "amenity." In addition, the result of analyzing relative importance of attributes of tunnel lighting facility shows that numbers of lighting array has the highest importance and lighting facility arrangement has the lowest importance. Result of analyzing partial utility shows that the 2 low type among number of lows, the solid line arrangement type between arrangement types, placing in the middle part among lighting facility arrangement were highly preferred. CONCLUSIONS : In the case of lighting numbers, utility values of the first line and the second line showed us a big difference. Increasing the number arrays in the future reformation of lighting facility installation combination will be effective in enhancing the utility of the driver.

직광에 의한 눈부심 현상이 터널 출구부 안전성에 미치는 영향 연구

PURPOSES : In Korea, over 70 percent of the land consists of mountainous and rolling area. Thus, tunnels continue its upward trend as road network are extended. In these circumstances, the importance of tunnel has been increased nowadays and then its safety investigation and research should be performed. This study is focus on confirming and improving the safety of tunnel. On tunnel hood, sunglare effect can irritate driver`s behavior instantly and this can result in incident. METHODS : The study of this phenomenon is rarely conducted in domestic and foreign papers, so there is no proper measure for this. This study analyzes the driving environment of the effect of sunglare effect on tunnel hood. RESULTS : Traffic accidents stem from complex set of factors. This study build the Traffic Accident Prediction Models to find out the effect of sunglare effect on tunnel`s hood. The independent variables are traffic volume, geometric design of road, length of tunnel and road side environment. Using these variables, this model estimates accident frequency on tunnel hood by Poisson regression model and Negative binomial regression model. Although Poisson regression model have more proper goodness of fit than Negative binomial regression model, Poisson regression model has overdipersion problem. So the Negative binomial regression model is used in this analysis. CONCLUSIONS : Consequently, the model shows that sunglare effect can play a role in driving safety on tunnel hood. As a result, the information of sunglare effect should be noticed ahead of tunnel hood so this can prevent drivers from being in hazard situation.

Optimization Support Controlling Large Deformation of Tunnel in Deep Mine based on Discontinuous Deformation Analysis

Field investigation and numerical analysis both show that the effects of multi-dynamic pressure on the tunnel deformation and failure in Qianjiaying coal mine are the main reasons, namely, the dynamic pressure of mining adjacent coal seams, the dynamic pressure due to the effects of mining the upper coal seams on the down coal seams and the advance dynamic pressure of coal seam. Field data indicate that the horizontal displacement is more than vertical displacement, which mainly due to the horizontal stress greater than the vertical stress. Through discontinuous deformation analysis (DDA), we have analyzed the shortage of the old support design, and put forward the revised support design. The functions of three adopted cables are different, namely, the middle cable is used to control the displacement of roof strata, and both sides cable are used to transfer the stress of the overlying strata. The corner bolts are used to control the squeezing pressure of two sides of tunnel, so as to effectively control the floor heave of tunnel. Based on DDA analysis, the failure process, deformation field, stress field and damage scope of tunnel under different support design have been investigated. Results have indicated that the DDA method is the potential method to optimize the bolting support design for coal tunnel.

Analysis and Design Approach for Large Storage Caverns

AbstractThis paper presents a case study of an underground crude oil storage project. This storage site is researched with detailed field and laboratory investigations. The layout, cross section, and elevation of the caverns are analyzed and designed based on geological and geotechnical information obtained during these investigations. In this study, two-dimensional (2D) elastoplastic analysis is performed using the finite-element code Phase 2D to study the rock mass behavior caused by staged excavation of the cavern (20 m wide×30 m high). The excavation of the cavern is simulated with different stages, i.e., excavation of a pilot tunnel and subsequent side slashing followed by excavation for a pilot bench and subsequent side slashing with a total of three benches. Displacement values obtained analytically are compared with the observed displacement as the excavation progresses. Because the 2D FEM code is based on the plain strain concept, it could not take into account the effect of excavation in other d...

The development of the small pierced test system on the far side of the shield tunnel

The development of the small pierced test system on the far side of the shield tunnel

Study of rock evaluation with tunnel side wall image in TBM pilot tunnel

Study of rock evaluation with tunnel side wall image in TBM pilot tunnel

Alterations in the β flap and β' dock domains of the RNA polymerase abolish NusA-mediated feedback regulation of the metY-nusA-infB operon.

The RimM protein in Escherichia coli is important for the in vivo maturation of 30S ribosomal subunits and a ΔrimM mutant grows poorly due to assembly and translational defects. These deficiencies are suppressed partially by mutations that increase the synthesis of another assembly protein, RbfA, encoded by the metY-nusA-infB operon. Among these suppressors are mutations in nusA that impair the NusA-mediated negative-feedback regulation at internal intrinsic transcriptional terminators of the metY-nusA-infB operon. We describe here the isolation of two new mutations, one in rpoB and one in rpoC (encoding the β and β' subunits of the RNA polymerase, respectively), that increase the synthesis of RbfA by preventing NusA from stimulating termination at the internal intrinsic transcriptional terminators of the metY-nusA-infB operon. The rpoB2063 mutation changed the isoleucine in position 905 of the β flap-tip helix to a serine, while the rpoC2064 mutation duplicated positions 415 to 416 (valine-isoleucine) at the base of the β' dock domain. These findings support previously published in vitro results, which have suggested that the β flap-tip helix and β' dock domain at either side of the RNA exit tunnel mediate the binding to NusA during transcriptional pausing and termination.

Structural and Biochemical Elucidation of Mechanism for Decarboxylative Condensation of β-Keto Acid by Curcumin Synthase

The typical reaction catalyzed by type III polyketide synthases (PKSs) is a decarboxylative condensation between acyl-CoA (starter substrate) and malonyl-CoA (extender substrate). In contrast, curcumin synthase 1 (CURS1), which catalyzes curcumin synthesis by condensing feruloyl-CoA with a diketide-CoA, uses a β-keto acid (which is derived from diketide-CoA) as an extender substrate. Here, we determined the crystal structure of CURS1 at 2.32 Å resolution. The overall structure of CURS1 was very similar to the reported structures of type III PKSs and exhibited the αβαβα fold. However, CURS1 had a unique hydrophobic cavity in the CoA-binding tunnel. Replacement of Gly-211 with Phe greatly reduced the enzyme activity. The crystal structure of the G211F mutant (at 2.5 Å resolution) revealed that the side chain of Phe-211 occupied the hydrophobic cavity. Biochemical studies demonstrated that CURS1 catalyzes the decarboxylative condensation of a β-keto acid using a mechanism identical to that for normal decarboxylative condensation of malonyl-CoA by typical type III PKSs. Furthermore, the extender substrate specificity of CURS1 suggested that hydrophobic interaction between CURS1 and a β-keto acid may be important for CURS1 to use an extender substrate lacking the CoA moiety. From these results and a modeling study on substrate binding, we concluded that the hydrophobic cavity is responsible for the hydrophobic interaction between CURS1 and a β-keto acid, and this hydrophobic interaction enables the β-keto acid moiety to access the catalytic center of CURS1 efficiently.

Test study on permeability properties of the sandstone specimen under triaxial stress condition

During the formation of mining space, the stress of rock within the scope of disturbance of mining redistributes, and a range of rock in front of and on the both sides of tunnel is damaged under concentration stress. Due to the change of the stress, some of cracks in damaged rock open and the others close, which greatly affects the flow of gas in rock. The change and development of cracks in rock and the unusual flow of gas are two main reasons that cause all kinds of gas accidents to happen in roadways. Based on this fact, a water seepage test was conducted in a sandstone specimen under triaxial stress condition by using MTS815.02 Electro-Hydraulic Servo-controlled Rock Mechanics Testing System. During the test, the deformation parameters and permeability of the specimen at twelve testing points were measured. Through the analysis of experimental results from a macroscopic perspective, the laws that the permeability changed respectively with axial strain, hoop strain and volumetric strain in the completely stress-strain process of the sandstone specimen were obtained. By comparison of influences of axial strain and hoop strain on the permeability in the completely stress-strain process of the sandstone specimen, it was concluded that hoop strain dominated the change of permeability at elastic stage and plastic stage of rock deformation under triaxial stress.

Numerical Analysis of Flow through a Hole for Modeling of Wind Tunnel Porous Wall

To model porous walls used in transonic wind tunnels, flow through a hole is investigated using Computational Fluid Dynamics (CFD). First, we analyze the relation between flow rate and differential pressure across the hole. At low differential pressures, such as for wind tunnel porous walls, the flow rate is found to increase linearly with differential pressure. We therefore propose a new model based on a linear relationship between flow rate and differential pressure. The effects of hole shape and boundary layer conditions near the hole are then investigated. In the outflow case (i.e., wind tunnel to plenum chamber), the flow rate increases as the ratio of hole depth to diameter becomes large due to variation of the flow separation area at the hole exit. Boundary layer thickness also affects the flow field: when the ratio of boundary layer thickness to hole diameter becomes small, the flow rate decreases, because the flow along wind tunnel side wall interacts more strongly with the flow through the hole.

Research on inversion high mining pressure distribution and technology of preventing dynamic disasters by MS monitoring in longwall face

Under two rock strata combination conditions, over 10,000 microseismic events were received with microseismic location monitoring technology which possessed by the author’s studying team, used in fully mechanized coal face of Huafeng Mine of Xinwen Coal Mining Group Co., Shandong Province. On the basis of the achievement of the location results, the conclusions were drawn as follows: On the basis of the achievement of 3D strata fracturing situation and the section plane of microseimic events in different areas, the relationship between spatial structure of overlying strata and mining pressure field was found, and we might describe distribution range of dynamic pressure of advance pressure and lateral stress around long face, and range of structure ad-tivation. Quantitative guidance to prevent dynamic disasters was provided. The practice in coal mine got a effective results. According to the FLAC3D soft numerical simulation of diameter drilling hole (the diameter is 300 mm) to relieve pressure in specified geological condition in Huafeng Mine, the right distance of two dirlls is 2.5 m and the right depth is 12 m. The research pro-vided basic guiding and practical experiences for the underground microseismic monitoring and disaster prevention in side slopes or tunnels engineering.

Xanthomonas campestris PqqD in the pyrroloquinoline quinone biosynthesis operon adopts a novel saddle‐like fold that possibly serves as a PQQ carrier

<i>Xanthomonas campestris</i> PqqD in the pyrroloquinoline quinone biosynthesis operon adopts a novel saddle‐like fold that possibly serves as a PQQ carrier

Lagrangian measurements of inertial particle accelerations in a turbulent boundary layer

Two-dimensional Lagrangian acceleration statistics of inertial particles in a turbulent boundary layer with free-stream turbulence are determined by means of a particle tracking technique using a high-speed camera moving along the side of the wind tunnel at the mean flow speed. The boundary layer is formed above a flat plate placed horizontally in the tunnel, and water droplets are fed into the flow using two different methods: sprays placed downstream from an active grid, and tubes fed into the boundary layer from humidifiers. For the flow conditions studied, the sprays produce Stokes numbers varying from 0.47 to 1.2, and the humidifiers produce Stokes numbers varying from 0.035 to 0.25, where the low and high values refer to the outer boundary layer edge and the near-wall region, respectively. The Froude number is approximately 1.0 for the sprays and 0.25 for the humidifiers, with a small variation within the boundary layer. The free-stream turbulence is varied by operating the grid in the active mode as well as a passive mode (the latter behaves as a conventional grid). The boundary layer momentum-thickness Reynolds numbers are 840 and 725 for the active and passive grid respectively. At the outer edge of the boundary layer, where the shear is weak, the acceleration probability density functions are similar to those previously observed in isotropic turbulence for inertial particles. As the boundary layer plate is approached, the tails of the probability density functions narrow, become negatively skewed, and their peak occurs at negative accelerations (decelerations in the streamwise direction). The mean deceleration and its root mean square (r.m.s.) increase to large values close to the plate. These effects are more pronounced at higher Stokes number. In the vertical direction, there is a slight downward mean deceleration and its r.m.s., which is lower in magnitude than that of the streamwise component, peaks in the buffer region. Although there are free-stream turbulence effects, and the complex boundary layer structure plays an important role, a simple model suggests that the acceleration behaviour is dominated by shear, gravity and inertia. The results are contrasted with inertial particles in isotropic turbulence and with fluid particle acceleration statistics in a boundary layer. The background velocity field is documented by means of hot-wire anemometry and laser Doppler velocimetry measurements. These appear to be the first Lagrangian acceleration measurements of inertial particles in a shear flow.

Three-dimensional characterization of the wind-borne pheromone tracking behavior of male hawkmoths, Manduca sexta

We studied the relationship between vertical and lateral movements during free flight odor plume tracking by male moths, Manduca sexta, in a wind tunnel with the "horizon" set at different altitudes. Three-dimensional recordings revealed that the plume tracking males generated roughly equivalent movements vertically and laterally regardless of horizon height. We hypothesized that the moths' tracks would be narrower in the vertical plane when they were presented with visual patterns on the tunnel's side walls. Instead, we discovered that their tracks tended to be wider in the horizontal plane. Anecdotal observations of other moth species describe plume tracking flight in three dimensions as "spiraling", suggesting a specific predictable relationship between vertical and lateral movements. However, we found that the relative phase, frequency, and amplitude of the vertical versus lateral movements vary on a maneuver-by-maneuver basis with no predictable temporal or spatial relationship. Our analyses suggest that a moth's trajectory in 3D can best be described as progressing upwind toward the source while cutting through the plume from all directions with loops of different radii. This is a more precise description than the terms "zigzagging" and "counter-turning" which were derived from 2D analyses of this behavior.

Polyphosphatase Activity of CthTTM, a Bacterial Triphosphate Tunnel Metalloenzyme

Triphosphate tunnel metalloenzymes (TTMs) are a superfamily of phosphotransferases with a distinctive active site located within an eight-stranded beta barrel. The best understood family members are the eukaryal RNA triphosphatases, which catalyze the initial step in mRNA capping. The RNA triphosphatases characteristically hydrolyze nucleoside 5'-triphosphates in the presence of manganese and are inept at cleaving inorganic tripolyphosphate. We recently identified a TTM protein from the bacterium Clostridium thermocellum (CthTTM) with the opposite substrate preference. Here we report that CthTTM catalyzes hydrolysis of guanosine 5'-tetraphosphate to yield GTP and P(i) (K(m) = 70 microm, k(cat) = 170 s(-1)) much more effectively than it converts GTP to GDP and P(i) (K(m) = 70 microm, k(cat) = 0.3 s(-1)), implying that a nucleoside interferes when positioned too close to the tunnel entrance. CthTTM is capable of quantitatively cleaving diadenosine hexaphosphate but has feeble activity with shorter derivatives diadenosine tetraphosphate and diadenosine pentaphosphate. We propose that the tunnel opens to accommodate the dumbbell-shaped diadenosine hexaphosphate and then closes around it to perform catalysis. We find that CthTTM can exhaustively hydrolyze a long-chain inorganic polyphosphate, a molecule that plays important roles in bacterial physiology. CthTTM differs from other known polyphosphatases in that it yields a approximately 2:1 mixture of P(i) and PP(i) end products. Bacterial/archaeal TTMs have a C-terminal helix located near the tunnel entrance. Deletion of this helix from CthTTM exerts pleiotropic effects. (i) It suppresses hydrolysis of guanosine 5'-tetraphosphate and inorganic PPP(i); (ii) it stimulates NTP hydrolysis; and (iii) it biases the outcome of the long-chain polyphosphatase reaction more strongly in favor of P(i) production. We discuss models for substrate binding in the triphosphate tunnel.

Shallow tunneling in unconsolidated ground with effective auxiliary method - Rokunohe tunnel in Tohoku Shinkansen -

This paper describes the results regarding the measurements and analysis to investigate the characteristics of ground surface settlement when a tunnel is advanced through unconsolidated ground. Rokunohe tunnel is a 3,810m long railway tunnel in Hachinohe Shin-Aomori section of Tohoku Shinkansen. It is located in almost flat diluvial Tableland (Sambongihara plateau) at elevation of 60m above sea level. The tunnel will pass beneath the public facilities such as roads, railways, water channels for agriculture. Hence, measurements of ground subsidence by using the auto tracking level were adopted to monitor the displacement of the ground resulting from the tunneling. 90 % to the total settlement has been occurred due to the excavation of upper and lower section. Shear deformation appears at the side of tunnel due to the invert excavation. These measurement data shows the needs of auxiliary methods with dewatering method to stabilize the tunnel. The numerical simulation was also applied in order to interpret the measurement results. The validation procedure of effective auxiliary methods based on the investigation are described.

Transonic turbine vane tests in a new miniature cascade facility

A new two-dimensional mini-cascade blow-down tunnel, with eight vane passages of only 20 mm true chord, 15 mm pitch, and 40 mm span, has been developed for testing gas turbine nozzle guide vane profiles at transonic exit Mach numbers ( M) and realistic Reynolds numbers ( Re) with a quick turnaround and high accuracy. The small size of the cascade has many advantages. Vane profiles can be tested at adjustable engine representative Re at room temperature with exit static pressures above atmospheric and Re and M can be independently varied. The mass flow is small and the long run times (&gt;3 min) allow downstream traversing with a three-hole miniature probe. The inaccuracies inherent in the traditional method of mounting the vanes/blades on pegs in the Schlieren windows have been eliminated by accurately computer numerical control (CNC) machining the whole cascade of vanes integral with the tunnel side walls, with re-usable, plug-in Schlieren windows. Cascades of new test vane profiles are quickly machined and tested, with a fast turn-around for comparative studies. A new Schlieren photography lens arrangement is demonstrated, which captures numerous flow visualization images per run directly into a digital SLR camera. Lower-than-atmospheric exhaust pressures were achieved by using a long exhaust designed to maximize exit flow dynamic pressure recovery using the self-ejector pumping effect. Exhaust pressures as low as 0.7 bar were achieved using the self-pumping exhaust, allowing M up to 1.6 with 3 bar inlet pressure and an exhaust at atmospheric pressure. An analytical model is developed for the mildly supersonic exit flow condition and validated against experimental data. Excellent agreement is achieved. Results presented for a typical transonic cascade show that the tunnel performs well in the subsonic and low supersonic region, but, as the exit M increases, shock-wave reflections from the free jet boundary, seen on the Schlieren, cause non-periodicity. Deep in the cascade, the flow is still periodic and can be used for investigations of loss and shock boundary-layer interaction. Interestingly, if the downstream pressure is reduced further to give even higher (but unrealistic) M, the cascade becomes axially supersonic and excellent periodicity is restored. Schlieren results are compared with computational fluid dynamics (CFD) simulations of the tunnel flow, and the loss measurements are validated against measurements conducted using a large-scale cascade at Göttingen.

A three-velocity-component laser-Doppler velocimeter for measurements inside the linear compressor cascade

A 24′′ (610 mm) access laser-Doppler velocimeter (LDV) system was developed to make simultaneous three-velocity-component measurements in a low speed linear cascade wind tunnel with moving wall simulation. The probe has a 610 mm access length and achieves a measurement spatial resolution of 100 μm by using off-axis optical heads. With the relatively large access length, the LDV probe allows for measurements from the side of a wind tunnel instead of through the tunnel floor, while the high spatial resolution allows for quality near-wall measurements. The probe has been tested in a zero-pressure gradient 2D turbulent boundary layer and the test results agree well with the experimental data measured with different LDV systems and hot-wire anemometery for the boundary layer flows. The energy spectral density was estimated using a slot correlation, and Von Karman’s model for the energy-spectrum function was used to analyze the measured spectral data to estimate the turbulent kinetic energy dissipation rate, which compares favorably with the measured production values in the log-layer region of the turbulent boundary layer. Measurements are presented for the moving endwall boundary layer at the inlet of the linear compressor cascade facility to validate the capability of this LDV for tip leakage flow measurements. These results indicate that the moving endwall reduces velocity gradients in the near-wall region and results in less production of Reynolds stresses and turbulent kinetic energy compared to the stationary endwall case.