• International conference on construction engineering and project management
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• 2013.01a
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• pp.367-374
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• 2013

Underground infrastructure systems provide essential public services and goods through buried structures including water and sewer, gas and petroleum, power and communication pipelines. The majority of existing underground infrastructure systems was installed in green field areas prior to development of complex urban built environments. Currently, there is a global trend to escalate major demand for underground infrastructure system renewal and new installation while minimizing disruption and maintaining functions of existing superstructures. Therefore, Engineers and utility owners are rigorously seeking technologies that minimize environmental, social, and economic impact during the renewal and installation process. Trenchless technologies have proven to be socially less disruptive, more environmentally friendly, energy conservative and economically viable alternative methods. All of those benefits are adequate to enhance overall sustainability. This paper describes effective sustainable solutions using trenchless technologies. Sustainability is assessed by a comparison between conventional open cut and trenchless technology methods. Sustainability analysis is based on a broad perspective combining the three main aspects of sustainability: economic; environmental; and social. Economic includes construction cost, benefit, and social cost analysis. Environmental includes emission estimation and environmental quality impact study. Social includes various social impacts on an urban area. This paper summarizes sustainable trenchless technology solutions and presents a sustainable construction method selection process in a proposed framework to be used in urban underground infrastructure capital improvement projects.

• Journal of the Korean GEO-environmental Society
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• v.16 no.9
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• pp.13-21
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• 2015

Recently, land subsidence and sinkhole are generated due to a change in the groundwater level in the city. For this reason, the necessity for management of stable underground water level is on the rise. In this study, it was conducted for the underground structure that passes through the lower of bus transfer center construction site to examine the influence on the stability for underground structures to changes in the groundwater level and effective stress, the coupled finite element analysis and structural analyses were performed to evaluate stability for underground structure. It is to secure stability for underground structures according to underground water level declines. In this way, effective construction management will be made by previewing and forecasting the influence on the ground behavior and adjacent structures due to changes in the groundwater level.

• Journal of the Korean GEO-environmental Society
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• v.22 no.11
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• pp.23-29
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• 2021

Recently, ground subsidence has been steadily occurring mainly in downtown areas, threatening the safety of citizens. Under the road, various underground facilities such as water supply pipe, sewage pipe, and communication pipe are buried. Due to the aging of these underground facilities and the reckless development of the underground, it is acting as a cause of ground subsidence. Although there is a result of analyzing the risk of ground subsidence according to the deterioration of the existing pipeline, there is no result of analyzing the risk of ground subsidence using the density of pipelines indicating ground disturbance. Therefore, in this study, the density of the underground space was analyzed using the data of six types of representative underground pipelines in Seoul, and a study was conducted on whether there is a correlation with the ground subsidence. As a result, it was found that the density of underground facilities is high in the area where the ground subsidence occurred, indicating that the density of pipelines have an effect on the ground subsidence.

• Geomechanics and Engineering
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• v.37 no.4
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• pp.307-321
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• 2024

This paper delves into the critical assessment of predicting sidewall displacement in underground caverns through the application of nine distinct machine learning techniques. The accurate prediction of sidewall displacement is essential for ensuring the structural safety and stability of underground caverns, which are prone to various geological challenges. The dataset utilized in this study comprises a total of 310 data points, each containing 13 relevant parameters extracted from 10 underground cavern projects located in Iran and other regions. To facilitate a comprehensive evaluation, the dataset is evenly divided into training and testing subset. The study employs a diverse array of machine learning models, including recurrent neural network, back-propagation neural network, K-nearest neighbors, normalized and ordinary radial basis function, support vector machine, weight estimation, feed-forward stepwise regression, and fuzzy inference system. These models are leveraged to develop predictive models that can accurately forecast sidewall displacement in underground caverns. The training phase involves utilizing 80% of the dataset (248 data points) to train the models, while the remaining 20% (62 data points) are used for testing and validation purposes. The findings of the study highlight the back-propagation neural network (BPNN) model as the most effective in providing accurate predictions. The BPNN model demonstrates a remarkably high correlation coefficient (R2 = 0.99) and a low error rate (RMSE = 4.27E-05), indicating its superior performance in predicting sidewall displacement in underground caverns. This research contributes valuable insights into the application of machine learning techniques for enhancing the safety and stability of underground structures.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2008.11a
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• pp.348-355
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• 2008

In Korea, the Seoul subway line 1 was opened in 1974 and the subway service is being operated in Seoul, Pusan, Daegu, Daejeon, and Inchon. The subway station is related to a underground shopping mall that was developed as complex spaces. According to the time of people's stay at the underground space, the necessity about the safety countermeasure of the underground space has been enlarged. Therefore the result of this study is t propose guidelines for improving the evacuation safety performance in underground subway stations.

• Journal of Power System Engineering
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• v.17 no.6
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• pp.136-141
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• 2013

This study introduces and analyzes the energy for heating and cooling system in region with volcano-stratigraphic. The thermodynamic properties of air through the air blower installed at the entrance of borehole are measured. It estimates the availability of underground air for heating and cooling system through experimental data and theoretical analysis. Based on our conclusion from these calculations we predict possibility of over 40kW steady and stable energy source from underground. Therefore this underground air can be utilized in region with volcano-stratigraphic.

• Journal of computational fluids engineering
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• v.10 no.1
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• pp.94-98
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• 2005

Accurate prediction of the fire-induced air velocity, temperature and smoke flow in underground utility tunnel becomes more important for the optimization of design and placement of heat and smoke detectors. In order to improve the safety of underground utility tunnel systems, the behaviors of fire-induced smoke flow and temperature distributions are investigated. Especially, two different cross-sectional shapes of tunnel, such as rectangular and circular types are modeled. Also, fire source is modeled as a volumetric heat source. Three-dimensional thermal-flow characteristics in an underground tunnel are solved by means of FVM using SIMPLE algorithm. The effects of shape geometry on the fire-induced flow characteristics are graphically depicted. It is desirable that heat and smoke detectors are installed on the cables and the top of the wall.

• Geomechanics and Engineering
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• v.17 no.6
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• pp.573-581
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• 2019

Excavation of underground cavern and shaft was proposed for the construction of a ventilation facility in an urban area. A shaft connects the street-level air plenum to an underground cavern, which extends down approximately 46 m below the street surface. At the project site, the rock mass was relatively strong and well-defined joint sets were present. A kinematic block stability analysis was first performed to estimate the required reinforcement system. Then a 3-D discontinuum numerical analysis was conducted to evaluate the capacity of the initial support and the overall stability of the required excavation, followed by a 3-D continuum numerical analysis to complement the calculated result. This paper illustrates the application of detailed numerical analyses to the design of the required initial support system for the stability of underground hard rock mining at a relatively shallow depth.

• Geomechanics and Engineering
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• v.25 no.3
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• pp.179-194
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• 2021

In this paper, to study the stability of surrounding rock during roadway excavation in different rock mass structures, the physical model test for roadway excavation process in three types of intact rock mass, layered rock mass and massive rock mass were carried out by using the self-developed two-dimensional simulation testing system of complex underground engineering. Firstly, based on the engineering background of a deep mine in eastern China, the similar materials of the most appropriate ratio in line with the similarity theory were tested, compared and determined. Then, the physical models of four different schemes with 1000 mm (height) × 1000 mm (length) × 250 mm (width) were constructed. Finally, the roadway excavation was carried out after applying boundary conditions to the physical model by the simulation testing system. The results indicate that the supporting effect of rockbolts has a great influence on the shallow surrounding rock, and the rock mass structure can affect the overall stability of the surrounding rock. Furthermore, the failure mechanism and bearing capacity of surrounding rock were further discussed from the comparison of stress evolution characteristics, distribution of stress arch, and failure modes in different schemes.

• Tunnel and Underground Space
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• v.10 no.2
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• pp.249-256
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• 2000

According to the industrial restructuring in the late 1980's, most domestic mines have been shutdown or suspended in operation. The closed underground excavation caverns remain in their abandoned conditions, and they will potentially cause environmental hazards. To evaluate the feasibility of the utilization of the abandoned caverns, the foreign crises were studied. As a result, we proposed several possible examples including underground storage cavern fur food products, underground compressed air energy system(CAES), and underground repository (or incineration plant) of industrial wastes. Among them, the underground waste repositories are most probable to be seen in Korea in the near future. For this, the study in rock engineering aspects should be conducted, which will include the establishment of support system and safety measure of the abandoned underground excavation caverns.