• Journal of Korean Tunnelling and Underground Space Association
• /
• v.17 no.2
• /
• pp.167-174
• /
• 2015

Since about 70 percent of the territory is mountainous, more tunnels are constructed in Korea for maximizing the development efficiency. With the increasing number of tunnel construction, safe construction in tunnels has been emerged as the utmost important subject. Recently, the number of long tunnel construction is steeply increased because of the request for high speed and straight road. In this study, a safe tunneling method using numerical modeling of rock blocks in long tunnels is proposed, and then applied to the long tunnel based on real discontinuity information observed in situ. It is possible to detect key blocks all along the tunnel exactly by using the numerical analysis program developed for the safe tunneling method using numerical modeling of rock blocks. This computer simulation method with user-friendly interfaces can calculate not only the stability of rock blocks but also the design of supplementary supports.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.6 no.3
• /
• pp.103-110
• /
• 2002

Maintenance monitoring of the tunnel which offers continuous data during and after tunneling has been applying to tunnels in order to meet the maintenance of tunnel and to confirm continuous security of the tunnel after tunneling. But, the maintenance monitoring of tunnel results for long period is not easy to find, and moreover, the rational analysis method on tunnel monitoring has not been established yet. In this study, the relationships between displacement and stress of the tunnel concrete lining using various analysis methods are compared with maintenance monitoring. The tunnel behavior were measured in the subway tunnel passing comparative soft the weathering and analyzed both security and mechanical characteristics of the tunnel concrete lining. Also, analyzed relationship between residual water pressure applied on tunnel design and one obtained by monitoring.

• Tunnel and Underground Space
• /
• v.15 no.3 s.56
• /
• pp.177-184
• /
• 2005

The Sapaesan tunnel, the longest twin tube tunnel (4km) in Korea with 4 lanes each, is under construction with two years of delayed schedule because of the strong opposition from environmental bodies. Therefore, maximizing the construction efficiency was needed in tunnel project to compensate for time delay. This study includes improvements in the construction of the Sapaesan tunnel such as increasing excavation length and changing excavation sequence. In this paper the system for predicting tunnel face ahead is also introduced. Bulk-Emulsion explosive and Cylinder-Cut method were adopted in tunnel blasting to increase the excavation length. Optimum tunnel excavation step was designed to make up delayed time. Tunnel foe mapping, TSP survey and geological prediction system using computerized jumbo-drill were performed fnr safe construction of long and large twin tube tunnel.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.13 no.6
• /
• pp.448-454
• /
• 2001

In the present study, the transient axi-symmetric numerical simulation of traffic ventilation induced by a train running through a 15.6km-long tunnel is performed by using over 100,000 computational cells. With train running, three cases of ventilation schemes are simulated, which are the case of ventilation fans turned on, the case of no fan but ventilation shafts open, and the case of no fan and no shaft. Results of the ventilation flow rate are pressure transients are compared for the cases considered.

• Explosives and Blasting
• /
• v.31 no.2
• /
• pp.32-39
• /
• 2013

Generally, The way of long hole blasting is carried out in coal-face, basic excavation for dam, mine etc. Recently, this long hole blasting has been implemented in civil engineering for efficiency & economic feasibility. National express no.600 of Pusan outer high-express ${\bigcirc}$ construction site with four lanes of the length of 8km was also a site applied by long hole blasting. But After blasting, tunnel advance rate is less than 75%. As a result of that, Follow-up working time is influenced. Thereby, The total of working process is significantly so increased that planned excavation cannot be implemented many times. For not only improve excavation rate but reduce working process time in job site, we introduce blasting case which apply the ${\phi}36mm$ explosive suited for high desity of charging among long hole blasting in order to overcome mentioned problem.

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.13 no.6
• /
• pp.463-499
• /
• 2011

Control of ground water is one of the most important factors for long-term operation of tunnel because most tunnels are located under the ground water level. In case of a drainage tunnel, there is no pore water pressure on the lining when the drainage system is properly working. After long-term operation, however, residual pore water pressure can be developed on the lining due to the deterioration of the drainage system. In this study, the water pressure distribution under obstruction condition of drainage material and conduit on the tunnel is numerically investigated using the ICFEP program and compared with the current value being applied to the residual water pressure for rational application plan of residual water pressure on the tunnel linings.

• Journal of the Korea Concrete Institute
• /
• v.14 no.3
• /
• pp.341-348
• /
• 2002

The purpose of maintenance monitoring is to offer the objective and continuous data in order to be lasting security affirmation and best fitted maintenance of tunnel structure. Though recently the examples of maintenance monitoring which Is applied to tunnel are rapidly increasing, long-term measured monitoring actual results and rationally analysis method researches are wholly lacking. In this study, it is analyzed that the relationship of stress and reinforcement stress of concrete lining, i.e., last support materials of tunnel through regression analysis based on the monitoring result of the subway tunnel, which was accomplished the monitoring for long period, passing the weathering. Also, through the analysis of the stress and the safety of concrete lining, it is estimated that the frequency of maintenance monitoring and the in-situ application of the criteria value of management.

• Geomechanics and Engineering
• /
• v.2 no.2
• /
• pp.107-123
• /
• 2010

Ground settlements and pore pressure changes were monitored around a shallow tunnel constructed in clay till during the excavation and primary lining installation. The settlements above the tunnel continued to develop for up to 100 days after the primary lining installation. Triaxial compression tests were carried out to estimate the short-term and long-term deformation characteristics of the till. Numerical simulation was conducted to history match the field measurements, and thus, to quantify the settlements induced by ground stress relief, consolidation and creep. It was found that the surface settlements due to ground stress relief, consolidation and creep are 17, 12 and 71% of total settlement (about 44 mm), respectively. In addition, early installation of rigid concrete lining could be an effective means to reduce the settlement due to creep.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.22 no.8
• /
• pp.1091-1100
• /
• 1998

Longitudinal distributions of the extinction coefficient and concentrations of hazardous gases in a long tunnel located in urban area haute been predicted theoretically. The results are compared with design criteria. It is found that the maximum concentrations of both CO and $NO_X$ in the tunnel are lower than the design criteria. However, the maximum extinction coefficient, generally considered to be a governing factor for ventilating flow rate, is shown lower than the design criterion. Therefore, it is suggested that the design criterion of the extinction coefficient should be increased to a slightly larger value.

• Structural Engineering and Mechanics
• /
• v.52 no.6
• /
• pp.1257-1271
• /
• 2014

The hydraulic deterioration of the drainage system in tunnel linings is one of the main factors governing long-term lining-ground interactions during the lifetime of tunnels. Thus, in the design procedure of a tunnel below the groundwater table, the possible detrimental effects associated with the hydraulic deterioration should be addressed. Hydraulic deterioration in double-lined tunnels can occur because of reasons such as clogging of the drainage layer and drain-pipe blockings. In this study, the coupled mechanical and hydraulic interactions between linings due to drain-pipe blockings are investigated using the finite-element method. A double-lined structural model incorporating hydraulic behavior is developed to represent the coupled structural and hydraulic behavior between the linings and drainage system. It is found that hydraulic deterioration hinders flow into the tunnel, causing asymmetric development of pore-water pressure and consequent detrimental effects to the secondary lining.