• Tunnel and Underground Space
• /
• v.15 no.5 s.58
• /
• pp.378-386
• /
• 2005

Jook-Ryung roadway tunnel was constructed by drill-blast after pilot tunnelling by 2 TBMS. nis report analyzes the data for TBM performance in the total length of 7.3 km for the two pilot tunnels. Net penetration rates were recorded as high as 2.3 m/h and 2.0 m/h for the two different directions while degrees of operation were $31.4\%$ and $33.3\%$, respectively. The cutter lives for No.2 tunnel were evaluated $200\~280\;m^3/c$ and around 400 m/set as high as for Meraker 10 km tunnel in Norway. The relationship between net penetration rate and characteristics of rock mass which were obtained by RMR and TSP measurement, coincides with the prior studies. This kind of evaluation is expected to be used to design TBM tunnelling and to help to perform the TBM operation effectively

• Tunnel and Underground Space
• /
• v.25 no.3
• /
• pp.255-263
• /
• 2015

Explosive blasting is a very useful tool for mining and civil engineering applications. It, however, may cause severe environmental hazards on adjacent structures due to blasting impact. Blast engineers try to make optimum blast design to provide efficient performance and to minimize the environmental impact as well. It requires a pre-assessment of the impacts resulting from the blasting operation in design stage. One of the common procedures is to evaluate the proposed blast pattern through a series of test blasting in the field. Another approach is to evaluate the possible environmental effects using the numerical methods. There are a number of input parameters to be prepared for the numerical analysis. Some of them are well understood, while some are not. This paper presents some results of sensitivity analysis of the basic input parameters in numerical modelling of blasting problems so as to provide sound understanding of the parameters and some guidelines for input preparation.

• Journal of the Korea Institute of Building Construction
• /
• v.20 no.3
• /
• pp.279-287
• /
• 2020

Recently, the demand for underground-type ammunition storage facilities has increased. Comparing with a ground-type ammunition storage facility, the underground-type ammunition storage facility can decrease the standard of safety distance because fragment and blast wave can be locked in the rock formation. However, the absence of a design method on the underground-type ammunition storage chamber became a major setback for the construction promotion. In this study, the process for designing an overall configuration of the underground-type ammunition storage facility was provided. First, the determination method for configuration and number of the chamber was developed by performing the ammunition storage simulation. Then, a tunnel (i.e., transfer channel for vehicles) and designed chambers can be arranged on the basis of safety distance standard. The safety distance standard also should be considered for determining the location and the size of entrances because of the blast wave and fragment effect at the entrances when an explosion is generated inside a chamber. In addition, considerations on the design for the waterproof and the drainage of subsurface water were analyzed through construction cases. Finally, an example of designing underground-type ammunition storage chambers was provided in order to verify the developed design process.

• Advances in concrete construction
• /
• v.9 no.6
• /
• pp.537-545
• /
• 2020

In order to reduce the usage of cement slurry in grouting engineering and consume the tunnel excavation waste soil, a new geopolymeric grouting material (GGM) was prepared by combine completely weathered granite (CWG) and blast-furnace slag (BFS), which can be applied to in-situ grouting treatment of completely weathered granite strata. The results showed CWG could participate in the geopolymerization process, and GGM slurry has the characteristics of short setting time, high flowability, low viscosity, high stone rate and high mechanical strength, and a design method of grouting pressure based on viscosity evolution was proposed. By adjusted the content of completely weathered granite and alkali activator concentration, the setting time of GGM were ranged from 5 to 30 minutes, the flowability was more than 23.5 cm, the stone rate was higher than 90%, the compressive strength of 28 days were 7.8-16.9 MPa, the porosity were below 30%. This provides a novel grouting treatment and utilizing excavated soil of tunnels in the similar strata.

• Tunnel and Underground Space
• /
• v.16 no.2 s.61
• /
• pp.179-188
• /
• 2006

The vibration or/and noise generated by blast operations might cause not only structural damage to properties but mentally also to humans and animals. For that reason, maximum permitted vibration and noise levels are set by sensitivities of structures and they are used for the management of blast vibration. It is known that the fish lived in water are more sensitive to vibration than land animals, and thus the adverse impact of the blasting on fish farms should be very concerned. This study investigated the vibration and noise levels at a large eel farm located some 840 meters of the blasting site through the large real-scale experiments of blastings, prior to conducting the actual blasting. As a result, it was found that the noise met the requirement to be within maximum permitted level, while the ground vibration exceeded the permitted vibration. Accordingly, the impact of the excess vibration was investigated by an existing empirical method and verified by a new three dimensional numerical analysis. In this study, such an inspection process was briefly described, and a method was suggested for the examination of possible adverse effects from blasting on vibration-sensitive structures like the eel farm. The study also introduced a design method that controls the blast effects - ground vibration and noise.

• Explosives and Blasting
• /
• v.41 no.3
• /
• pp.26-37
• /
• 2023

In order to determine the amount of explosives that can minimize the vibration generated during tunnel construction using the blasting method, it is necessary to derive the blasting vibration coefficients, K and n, by analyzing the vibration records of trial blasting in the field or under similar conditions. In this study, we aimed to develop a technique that can derive reasonable K and n when trial blasting cannot be performed. To this end, we collected full-scale trial blast data and studied how to predict the blast vibration coefficient (K, n) according to the type of explosive, center cut blasting method, rock origin and type, and rock grade using deep learning (DL). In addition, the correction value between full-scale and borehole trial blasting results was calculated to compensate for the limitations of the borehole trial blasting results and to carry out a design that aligns more closely with reality. In this study, when comparing the available explosive amount according to the borehole trial blasting result equation, the predictions from deep learning (DL) exceed 50%, and the result with the correction value is similar to other blast vibration estimation equations or about 20% more, enabling more economical design.

• Tunnel and Underground Space
• /
• v.24 no.1
• /
• pp.97-109
• /
• 2014

In order to identify the characteristics of the propagation depending on delay time (20, 25 ms) and priming location (top priming, middle priming, bottom priming), test blasts were carried out a total of 4 times using different spacing, burden, drilling length, charge per delay and was derived the formula to predict blast vibration. This study investigated the characteristics of vibration by analysis of the nomogram and prediction of Peak Particle Velocity (PPV) from delay time and priming location by the formula to predict ground vibration. And it analyzed the trends of vibration increase by standards charge 0.5, 1.6, 5, 15 kg. Standards charge is "Blasting design and construction guidelines to road construction" by the Ministry of Land, Infrastructure and Transport. Depending on the charge in favor of vibration control method is proposed. Thus, when the design was to be used as a variable.

• Explosives and Blasting
• /
• v.24 no.1
• /
• pp.29-37
• /
• 2006

The demand of the bulk emulsion explosives is being increased more and more by using the mechanization loading system in a domestic tunnel sites. Thus, a rational design criteria that is suitable for rock and circumstance condition has been required. In this study, authors investigated a optimum specific charging weight and resonable charging weight based on domestic blasting construction cases, which were performed by using a mechanization bulk emulsion explosives loading system up to now. Authors also analyzed the blasting results and got the following formula $({\Upsilon}= 0.669 + (0.0154{\times}RMR),\;r=0.81)$ from the relationship between a optimum specific charging weight of bulk exp. and rock mass rating. A range of resonable charging weight with a drilling depth is calculated considering a rock conditions.

• Smart Media Journal
• /
• v.10 no.4
• /
• pp.35-44
• /
• 2021

Recently, the new subway project called "Great Train Express" is in progress. During the tunnel excavation in the center of city, vibration and noise are generated, which make an uncomfortable effect on nearby residents. In order to prepare for this situation, the construction company generally establishes a noise and vibration management plan at the site from the construction planning stage through consultation with the residents of nearby areas and establishment of countermeasures for complaints raised. However, despite the establishment of a noise and vibration management plan, civil complaints have not been fundamentally resolved due to occurring noise and vibration during the construction in progress. In order to solve this problems, one of the best solution is to provide noise and vibration simulation technology with a high sense of reality and immersion for residents of nearby areas. Considering the ease and convenience of using the system, we intend to develop a UI(User Interface) necessary for the development of a simulation system that can directly experience the air blast and vibration based on virtual reality. The results of this study are expected to contribute to the development of virtual reality-based air blast and vibration simulations in the future.

• Tunnel and Underground Space
• /
• v.25 no.1
• /
• pp.46-55
• /
• 2015

A water tube with detonating cord was devised to control the blast dust. Water diffusion experiments with different detonating cord positions were conducted during the series of experiments to optimize the design parameters of the tube. Images from high speed camera were analyzed to evaluate the results. AUTODYN program was adopted to simulate the diffusion process of water and compared with the images. Diffusion of water shows cross flow in case of external charge while the internal case shows radial flow. A bubble ring was formed during the numerical analysis of internal charge case as occurred in underwater blast. An additional bubble ring was formed by the reflection pressure from the ground. And the Weber number was determined as sufficient for spray atomization performance of the water tube.