• Geotechnical Engineering
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• v.14 no.4
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• pp.17-32
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• 1998

has been much progress in theories and construction techniques to secure the stability of the underground structures. Recently, several studios have shown that it is possible to predict the existence of discontinuities ahead of a tunnel face by analyzing 3-dimensional absolute displacements measured during tunnel excavation. This paper concentrated on the development of a methodology to predict the existence and location of the discontinuities, or the void space(abandoned mine) , by performing 3-dimensional FEM analysis and considering the stress relocation caused by arching effect during excavation. Also, this study tried to verify deformation for choosing the most suitable support system. The results of this study might provide a way of safer and economical tunnel construction by utilizing the in-situ monitoring data.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.03a
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• pp.1046-1053
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• 2006

In the large scale recent reclaiming works performed within the wide spatial boundary, evaluation of long-term consolidation settlement and residual settlement of the whole construction area is sometimes made with the results of the limited ground investigation and measurement. Then the reliability of evaluation has limitations due to the spatial uncertainty. Additionally, in case of large scale deep excavation works such as urban subway construction, there are a lot of hazardous elements to threaten the safety of underground pipes or adjacent structures. Therefore it is necessary to introduce a damage prediction system of adjacent structures and others. For the more accurate analysis of monitoring information in the wide spatial boundary works and large scale urban deep excavations, it is necessary to perform statistical and spatial analysis considering the geographical spatial effect of ground and monitoring information in stead of using diagrammatization method based on a time-series data expression that is traditionally used. And also it is necessary that enormous ground information and measurement data, digital maps are accumulated in a database, and they are controlled in a integrating system. On the abovementioned point of view, we developed Geomonitor 2.0, an Internet based real time monitoring program with a new concept by adding GIS and geo-statistical analysis method to the existing real time integrated measurement system that is already developed and under useful use. The new program enables the spatial analysis and database of monitoring data and ground information, and helps the construction- related persons make a quick and accurate decision for the economical and safe construction.

• KSBB Journal
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• v.16 no.6
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• pp.527-532
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• 2001

Trichlooethylene (TCE) has become a widespread contaminant in air, soil, and underground water due to extensive industrial used and improper disposals. Since TCE is a suspected carcinogen and constitutes public health concerns, many treatment systems have been investigated to remove this hazardous waste. One of the most premising reactor systems for the treatment of TCE is trickling biofilter (TBF), in which monooxygenase (MO), the corresponding enzyme for initiating primary substrate oxidation, fortuitously degrades TCE via cometabolism. TCE, however, is not easily treated by simple TBF. This is mainly due to the toxicities of TCE and its degradation products to microbial film in TBF. In this paper, recent progresses on the development of bioreactor system for the treatment of TCE, especially gas-phase TCE, are reviewed. The potentials of novel biofilm reactor systems were also discussed for the long-term continuous treatment of TCE.

• Spatial Information Research
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• v.21 no.3
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• pp.55-69
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• 2013

In the modern society, as the city grows and constructive technology gradually develops, land usage has been sophisticated and three-dimensionalized. Consequently, issues such as property ownership and legal claim over ground and underground space have been triggered, which disclose the problems of using two-dimensional cadastral management system. Numerous researches on building three-dimensional cadastral are ongoing such as defining the right relationship of land space and providing the registration and management scheme so as to solve the imminent matter. It is the chief aim of this study to increase efficiency by analyzing the vocational practices through adding on necessary sections and properties for current registration to original research work. If three-dimensional cadastral management system is once constructed, highly qualified services for citizens will be available by providing accurate land related information swiftly, which can result in inevitable improvement of efficiency at work. Hence, this thesis will suggest the internationally suitable feature model development method in terms of standardization by probing into the factual profession to derive each attributes and properties that are related to three-dimensional cadastral and affix them to the classified item requisites of initial research studies.

• 한국터널공학회:학술대회논문집
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• 2005.04a
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• pp.233-247
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• 2005

Most tunnel lining material which has been used in the domestic is a concrete. But many problems as the construction period, the cost, and the crack occurrence for the design, construction, and management were happened in the concrete lining. For this reason, many research institutes like the Korea Highway Corporation recognize the necessity of an alternate material development and grow on the interest for that. So in this study, the seismic behaviour characteristics for the application of the Corrugated Steel Plate Lining in cut-and-cover tunnel are evaluated as several conditions for the backfill height, the cutting slope, and the relative density of backfill soil are changed. The compressive stress which is calculated in the Corrugated Steel Plate Lining by the seismic load is decreased as the backfill height increases and the cut slope grows gentle. Also, the moment shows the tendency of decrease according to the increase of the backfill height. But in the case of the relative density of the backfill soil is small, the moment increases according to the increase of the backfill height and affects the dynamic behaviour characteristic. So it is considered that the relative density of the backfill soil is also the important point. As the result in analyzing the seismic response characteristics of the reinforcement spacing of the Corrugated Steel Plate, the variation in the compressive force is hardly happened, but the moment and the shear force increase on the reinforcement spacing being narrow.

• Journal of the Korea Society for Simulation
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• v.21 no.2
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• pp.1-9
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• 2012

Subterranean termites forage by constructing tunnel networks in soil and encounter food resources during tunnel excavation. Some species of termites can travel up to 150 m underground. They often travel to the surface to find wood cellulose to feed their colony, which in turn causes extensive damage to wooden architecture, such as timber-frame houses. This type of damage has been constantly increasing along with global warming because higher temperatures provide an ecological niche for termites. The damage is closely related to termite territory size and distribution. Recently, as a way to research termite control, the necessity of a mathematical model to simulate termite territory formation in relation to damage has increased. So far, however, few studies have been conducted on the development of a model because it is difficult to quantify or characterize the relationship between territorial behavior and field conditions including complicated environmental factors. In the present study, we suggest a simulation model of the territoriality of the Formosan subterranean termites, Coptotermes formosanus (Shiraki), and Reticulitermes flavipes (Kollar), based on empirical data. The model consists of 2 procedures. One describes tunnel network growth for each colony, and the other represents territoriality based on tunnel-tunnel interactions between different colonies. Using the model, we show changes in territorial competition according to the termination probability of tunnel growth.

• Explosives and Blasting
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• v.24 no.1
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• pp.9-19
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• 2006

The objective of this study is to propose curve fitted equations that can facilitate calculations and improve a practical applicability when the seismic performance of buried pipelines needs to be evaluated. The curve fitted equations are derived based on the evaluation of the dynamic responses of concrete pipe with a boundary condition of fixed-free ends. To study the dynamic response of underground pipe, the numerical analysis program developed in the previous research has been used. The location of maximum strain has been determined through dynamic analyses for a boundary condition of fixed-free ends. Then $wavelength{\lambda}$ of 5-1000(m) and propagation velocity(Vs) of 100-2000(m/s) have been applied at the location of maximum strain and the unit srain curve with the changes of the $wavelength{\lambda}$ and propagation velocity(Vs) has been obtaind. Non-linear least-square regression has been used to develop highly applicable curve fitted equations and various types of exponential regression equations have been checked out. Thus curve fitted equations and necessary coefficients with best results are suggested.

• Tunnel and Underground Space
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• v.10 no.3
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• pp.366-377
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• 2000

The development of proper joint model, which can describe real phenomena exactly and still can be used easily, is one of the most important element for the analysis of the mechanical and hydraulic behavior of discontinuous rock mass. In this study, an elasto-plastic constitutive model of joint behavior considering asperity degradation was extended with the concept of first and second order asperities. The proposed model was implemented to numerical code with discrete finite joint element. The parametric study with the various asperity angles and degradation coefficients showed that the model can reproduce the shear behavior of typical rough joints well. Results of laboratory monotonic and cyclic shear tests were compared with those of numerical tests to validate the model. The hydraulic model considering the relations between gouge production and aperture was introduced to the mechanical mode1. In an attempt to examine the performance of the model, comparative numerical test was conducted. Permeability between joint surfaces increased rapidly at the first stage, but became nearly constant with increasing shear displacement due to gouge production and uniform variation of aperture distribution.

• Tunnel and Underground Space
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• v.21 no.3
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• pp.181-191
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• 2011

It is very difficult to prepare a lab. test specimen from weak rock masses affected by faults, highly fractured zone or weathered zone. In conventional method of in situ direct shear test a rock block is sheared inside galleries, where reactions for the hydraulic jacks are available. A new in situ direct shear test apparatus has been developed in this study to perform the test inside galleries as well as open pit conditions. The apparatus is composed of normal and shear reaction plates including load transfer plates, hydraulic cylinder systems, load cells, multistage shear boxes with fixing devices, and needle rollers. Maximum size of the test block is $400{\times}400{\times}460$ mm, and procedures of the test block preparation has been suggested. To explore the field applicability of in situ direct shear test apparatus, proper test block site was investigated by extensive geological field survey. In situ direct shear test has been successful in producing most of information related to strength and deformability of the weak rock.

• Tunnel and Underground Space
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• v.27 no.1
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• pp.58-68
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• 2017

According to the development of optical technology, the capacity of LIDAR equipments has been greatly improved to get rock mass characteristics precisely and accurately enough and it has been lightened and popularized so that it can be easily used in the field. In this study, we examined the applicability of roughness measurement for joints in a rock slope using LIDAR technique. A triangular irregular network was constructed using LIDAR and a patch, which is a plane structure of discontinuity on rock mass measured from LIDAR scanning, was extracted to estimate the roughness of the rock slope. Four different kinds of roughness parameters were analyzed to find out their correlation with JRC for various point intervals. Among them, $R_s$ parameter was used to measure the roughness of a patch. Regression analysis between four roughness parameters and JRC with respect to point interval was performed. All the roughness parameters decreased with the increase of point interval. In addition, the parameter value showed greater decrease for rougher surfaces. A method of roughness measurement using $R_s$ parameter on rock slope discontinuities was suggested which showed slight overestimation of the real roughness value.