• Journal of the Korean Society of Industry Convergence
• /
• v.5 no.4
• /
• pp.313-320
• /
• 2002

A 2-dimensional $k-{\varepsilon}$ numerical model was developed to explore the effects of vehicle movement, jet fan and wind speed for the ventilation of road tunnels. To consider the temperature distribution in the tunnel, the energy equation was solved with a source term of the energy exhausted from vehicles. Although the tunnel ventilation can be made by the piston effect of vehicle movement, an additional ventilation is necessary when a head wind is existing. Jet fans may assist the air flow in the tunnel. However, more efficient ventilation system should be necessary, because the exhaust gas from vehicles flow along the road surface and it cannot be diffused in the longitudinal tunnel.

• Journal of Korean Neurosurgical Society
• /
• v.65 no.2
• /
• pp.307-314
• /
• 2022

Objective : The percutaneous thread transection technique is a surgical dissecting method using a dissecting thread inserted through a needle under ultrasound guidance without skin incision. As the new dissecting threads were developed domestically, this cadaver study was conducted to compare the effectiveness and safety between the new threads (ultra V sswire and smartwire-01) and a pre-existing commercial dissecting thread (loop & shear) by demonstrating a modified looped thread cubital tunnel release. Methods : The percutaneous cubital tunnel release procedure was performed on 29 fresh cadaveric upper extremities. The pre-existing commercial thread was used in 5 upper extremities. The two newly developed threads were used in 24 upper extremities. Two practitioners performed the procedures separately. After the modified looped thread cubital release, anatomical and histological analyses were performed by a blinded anatomist. The presence of the dissected cubital tunnel and damaged adjacent soft tissue was assessed. Results : Out of the 29 cadaveric upper extremities, 27 specimens showed complete dissection of the Osborne ligament and the proximal fascia of the flexor carpi ulnaris muscle. One specimen was incompletely dissected in each of the ultra V sswire and smartwire-01 groups. There were no injuries of adjacent structures including the ulnar nerve, ulnar artery, medial antebrachial cutaneous nerve, or flexor tendon with either the commercial thread or the newly developed threads. The anatomical analysis revealed clear and sharp incisional margins of the cubital tunnel in the Smartwire-01 and loop & shear groups. All three kinds of threads maintained proper linear elasticity for easy handling during the procedure. The smartwire-01 provided higher visibility in ultrasound than the other threads. Conclusion : The newly developed threads were effective and safe for use in the thread cubital tunnel release procedure.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.33 no.4
• /
• pp.1529-1539
• /
• 2013

Recent case studies in Japan have shown that rockbolts are commonly installed at an oblique angle to the excavation direction of the tunnel, instead of at a right angle, due to restriction of the working space. In particular, in the case of expansion in an existing tunnel, the working space can be very small, due to the large protective structures necessary to operate within an existing tunnel. In this case, where both the current use of the existing tunnel, and the reinforcement of the ground around the tunnel are required, the effects of installation angles and patterns of rockbolts are important factors in the design process. Therefore, in this study, a total number of 24 model tests are performed, to investigate the reinforcing effects of system bolting installed obliquely from the excavation direction of the tunnel, by changing the installation angle of bolts, longitudinal distance, and bonded length of bolts. The model test results indicate that the relaxed load ratio decreases, with the increase of both the bonded lengths and the number of the installed bolts, resulting in the decrease of the supported area by one bolt. Two-dimensional numerical analysis, which considered the reinforcement effect of inclined system bolting as the change of engineering properties near the tunnel, demonstrated that the deflection patterns at the tunnel crown in the numerical simulations, show a similar tendency to those measured in the model tests.

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.3 no.4
• /
• pp.35-55
• /
• 2001

Recently, as tunnel structures are getting older and decrepit, many tunnel inspections are carried out for evaluating the tunnel state and safety. But, because there is no exact standard for tunnel state and safety, depending on subjective decision, the new standard to assess the tunnel state is required. The existing standard including mainly the assessment of the state of tunnel lining is not considered the characteristics of tunnel as underground structures. Also, the item of assessment and process of grading and classifying the state of tunnel is not objective and systemetic. In this study, new standard for assessment of tunnel state is presented for improving the problems in evaluating the tunnel state and safety. In the new standard, the new items of assessment including geotechnical condition were selected and graded, the process in classifying the tunnel state is quantitative for objective assessment for tunnel state. This new standard and method is practically used in effective safety inspection and diagnosis and tunnel maintenance.

• Geomechanics and Engineering
• /
• v.36 no.6
• /
• pp.563-573
• /
• 2024

In this study, various countermeasures used to mitigate tunnel deformations due to nearby multi-propped basement excavation in soft clay are explored by three-dimensional numerical analyses. Field measurements are used to calibrate the numerical model and model parameters. Since concrete slabs can constrain soil and retaining wall movements, tunnel movements reach the maximum value when soils are excavated to the formation level of basement. Deformation shapes of an existing tunnel due to adjacent basement excavation are greatly affected by relative position between tunnel and basement. When the tunnel is located above or far below the formation level of basement, it elongates downward-toward or upward-toward the basement, respectively. It is found that tunnel movements concentrate in a triangular zone with a width of 2 H_e (i.e., final excavation depth) and a depth of 1 D (i.e., tunnel diameter) above or 1 D below the formation level of basement. By increasing retaining wall thickness from 0.4 m to 0.9 m, tunnel movements decrease by up to 56.7%. Moreover, tunnel movements are reduced by up to 80.7% and 61.3%, respectively, when the entire depth and width of soil within basement are reinforced. Installation of isolation wall can greatly reduce tunnel movements due to adjacent basement excavation, especially for tunnel with a shallow burial depth. The effectiveness of isolation wall to reduce tunnel movement is negligible unless the wall reaches the level of tunnel invert.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2005.10a
• /
• pp.550-555
• /
• 2005

In vicinity of Seoul, there has been water service tunnel that classified into 1st grade facility by special act for the safety control of public structures and with providing capacity equals to $1,543{\times}10^3$(ton/day) and inner pressure equals to $2.5-3.5kg/cm^2$. In this research, site investigation and stability analysis for water tunnel caused by new construction of road tunnel were carried out. the ground near water tunnel were zoned into spatial area having similar geotechnical characteristics and estimating geotechnical properties for each area. The site for analysis consists of banded biotite gneiss, biotite schist and granite gneiss with spatial non-homogeneity, and for that reason weathering and fault zone were distributed with large scale. It's important thing to consider spatial ground zone and their geotechnical properties properly into stability analysis at design and construction stage. Also, using results of site investigation, stability of existing tunnel have been analyzed for Hydraulic Fracture/Jacking and deformation in detail.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2002.03a
• /
• pp.213-220
• /
• 2002

Generally it is informed that urethane materials are superior to the others in physical characteristics, durability, ground improvement and the influence to environment . But, the existing urethane methods are too expensive to apply. So this study has analyzed the applicability of TAS method which has developed the existing urethane injection mechanism. From the results, Extending the max-infection distance over l0m from 6m which the existing methods could inject to, TAS method has proved to be economical. Also, the TAS method is obtained quickly to ground improvement effect in various tunnel constructions because rise-time was relatively shorter than that of cement-grouting. Therefore, it is expected that TAS method would be applied a lot for water proof and ground improvement etc. owing to its many advantages mentioned the above.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2014.04a
• /
• pp.487-490
• /
• 2014

These Days a lot of Noise Complaints in vicinity of Railway has been more increase than before. Almost 1/3 Residences who lives in Railway side are Exposure to Noise Pollution. Since the Apartment Buildings around Railway are getting more higher, so those of the Noise Barrier are not best solution anymore. We are going to make a New Plane with the state of the art technology for Railway Noise Abatement Control. Our Goal are focus on a development of Light Weight Noise Tunnel designed by new absorption mat'l and tunnel Stucture on the Overbridge and Viaduct of existing Railway. New Noise Tunnel will be reducing their weight more than 30% against Road Traffic One and also 10dB(A) Noise Reduction against Noise Barrier.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.63 no.8
• /
• pp.1140-1145
• /
• 2014

Tunnel lighting is composed of entrance zone, interior zone and exit zone by KS C 3703. We have to consider adaptation at entrance zone and exit zone lighting to prevent deteriorate visibility like black hole and white hole phenomenon. So External luminance, vehicle velocity and traffic volume should be considered in threshold zone lighting and vehicle speed and traffic volume should be considered in interior zone lighting. But existing tunnel lighting system is not good at visibility and economic because that is only controled by external luminance. So in this paper, We improve visibility and economic of tunnel lighting system using fuzzy reasoning according to external luminance, vehicle velocity, traffic volume.

• Ocean Systems Engineering
• /
• v.1 no.4
• /
• pp.297-315
• /
• 2011

New applications of streamlined Autonomous Underwater Vehicles require an AUV capable of completing missions with both high-speed straight-line runs and slow maneuvers or station keeping tasks. At low, or zero, forward speeds, the AUV's control surfaces become ineffective. To improve an AUV's low speed maneuverability, while maintaining a low drag profile, through-body tunnel thrusters have become a popular addition to modern AUV systems. The effect of forward vehicle motion and sideslip on these types of thrusters is not well understood. In order to characterize these effects and to adapt existing tunnel thruster models to include them, an experimental system was constructed. This system includes a transverse tunnel thruster mounted in a streamlined AUV. A 6-axis load cell mounted internally was used to measure the thrust directly. The AUV was mounted in Memorial University of Newfoundland's tow tank, and several tests were run to characterize the effect of vehicle motion on the transient and steady state thruster performance. Finally, a thruster model was modified to include these effects.