• Title/Summary/Keyword: Ground subsidence

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Effect of Ground Subsidence on Reliability of Buried Pipelines (지반침하가 매설배관의 건전성에 미치는 영향)

  • 이억섭;김동혁
    • Journal of the Korean Society for Precision Engineering
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    • v.21 no.1
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    • pp.173-180
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    • 2004
  • This paper presents the effect of varying boundary conditions such as ground subsidence, internal pressure and temperature variation for buried pipelines on failure prediction by using a failure probability model. The first order Taylor series expansion of the limit state function incorporating with von-Mises failure criteria is used in order to estimate the probability of failure mainly associated with three cases of ground subsidence. Using stresses on the buried pipelines, we estimate the probability of pipelines with von-Mises failure criterion. The effects of varying random variables such as pipe diameter, internal pressure, temperature, settlement width, load for unit length of pipelines, material yield stress and pipe thickness on the failure probability of the buried pipelines are systematically studied by using a failure probability model for the pipeline crossing ground subsidence regions which have different soil properties.

Reliability Estimation of the Buried Pipelines for the Ground Subsidence (지반침하에 대한 매설배관의 건전성 평가)

  • 이억섭;김의상;김동혁
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2003.06a
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    • pp.1557-1560
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    • 2003
  • This paper presents the effect of varying boundary conditions such as ground subsidence on failure prediction of buried pipelines. The first order Taylor series expansion of the limit state function is used in order to estimate the probability of failure associated with three cases of ground subsidence. We estimate the distribution of stresses imposed on the buried pipelines by varying boundary conditions and calculate the probability of pipelines with von-Mises failure criterion. The effects of random variables such as pipe diameter, internal pressure, temperature, settlement width, load for unit length of pipelines, material yield stress and thickness of pipeline on the failure probability of the buried pipelines are also systematically studied by using a failure probability model for the pipeline crossing a ground subsidence region.

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A Study on the Upper Ground Reinforcement Effect in Underground Cavern (지하공동 상부지층 보강효과에 관한 연구)

  • Kim, Ki Ho;Lim, Jong Se;Jang, Won Yil
    • Tunnel and Underground Space
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    • v.25 no.3
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    • pp.275-283
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    • 2015
  • Excavation of underground space in soft ground implicate to the structure, such as subsidence. As a result, it has been acting as a serious risk to the stability of the roads and facilities. Therefore, in order to stabilize the soil stabilization and reinforcement of the structure, we have been using a number of methods and injecting material. In this study, we compared and analyzed the amount of subsidence regarding the ground reinforcement during underground excavation in soft ground by performing model test. And three-dimensional numerical analysis was performed using FLAC 3D. The subsidence was simulated numerically according to the tunnel excavation. The subsidence results of the model tests and numerical analyzes were relatively consistent. Thus comparing the ground subsidence by varying the reinforcement area on the numerical analysis was analyzed. As a results, three-dimensional numerical simulation could be regarded to simulate better on the ground subsidence by various kinds of underground excavation and it can be used as a material of subsidence prevention methods.

Analysis of Ground Subsidence Influencing Factors Using Underground Facility Property Information (지하매설물 속성정보를 활용한 지반함몰 영향인자 분석)

  • Jaemo Kang;Sungyeol Lee;Jinyoung Kim;Myeongsik Kong
    • Journal of the Korean GEO-environmental Society
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    • v.25 no.1
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    • pp.5-11
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    • 2024
  • Ground subsidence mainly occurs in urban areas with high population density, so it is necessary to clearly identify the cause of occurrence and prepare in advance. The main cause of ground subsidence is reported to be the creation of cavities in the ground due to damage to underground pipes, but the property information and influencing factors of underground pipes to predict and prepare for ground subsidence are not properly established. Therefore, in this study, factors showing a significant correlation with the occurrence of ground subsidence were selected among the underground facility property information and a regression equation was proposed through logistic regression analysis. For this purpose, data on underground structures and ground subsidence history information in the target area were collected, and the target area was divided into girds of 100m x 100m in size using QGIS. The underground facility attribute information and ground subsidence history information contained within the gird were extracted. Then, preprocessing was performed to construct a dataset and correlation analysis was performed. As a result, factors excluding the year of sewer pipes and communication pipes and the average depth of communication pipes, heat pipes, and gas pipes were found to have a significant correlation with ground subsidence. In addition, a regression equation for whether ground subsidence occurred in the target area is proposed through logistic regression analysis.

Ground Subsidence Risk Grade Prediction Model Based on Machine Learning According to the Underground Facility Properties and Density (기계학습 기반 지하매설물 속성 및 밀집도를 활용한 지반함몰 위험도 예측 모델)

  • Sungyeol Lee;Jaemo Kang;Jinyoung Kim
    • Journal of the Korean GEO-environmental Society
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    • v.24 no.4
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    • pp.23-29
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    • 2023
  • Ground subsidence shows a mechanism in which the upper ground collapses due to the formation of a cavity due to the movement of soil particles in the ground due to the formation of a waterway because of damage to the water supply/sewer pipes. As a result, cavity is created in the ground and the upper ground is collapsing. Therefore, ground subsidence frequently occurs mainly in downtown areas where a large amount of underground facilities are buried. Accordingly, research to predict the risk of ground subsidence is continuously being conducted. This study tried to present a ground subsidence risk prediction model for two districts of ○○ city. After constructing a data set and performing preprocessing, using the property data of underground facilities in the target area (year of service, pipe diameter), density of underground facilities, and ground subsidence history data. By applying the dataset to the machine learning model, it is evaluated the reliability of the selected model and the importance of the influencing factors used in predicting the ground subsidence risk derived from the model is presented.

Analysis of Ground Subsidence on Gyochon Residential Region of Muan City (무안 교촌리주거지역 지반침하 안정성 분석)

  • Han, Kong-Chang;Cheon, Dae-Sung;Ryu, Dong-Woo;Park, Sam-Gyu
    • Tunnel and Underground Space
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    • v.17 no.1 s.66
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    • pp.66-74
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    • 2007
  • The analysis of ground subsidence stability was conducted for the residential area located on the limestone corrosion zone. For the investigation of the cavity distribution in limestone region, various geophysical investigations such as electroresistivity tomography, electromagnetic prospecting are carried out. Geotechnical field tests with drilling are also carried out for the evaluation of the ground characteristics. Based upon their results, numerical modeling is performed for the simulation and prediction of the ground subsidence with the conditions of cavity geometry and groundwater level. The main factor to cause the ground subsidence is estimated as the draw down of the groundwater level below soil overburden, which disturbs the mechanical equilibrium of ground and drives washing away the overburden soil through the cavity and solace subsidence. It seemed that it is essential to maintain the groundwater level continuously above the shallow cavity for the prevention of the ground subsidence on the limestone corrosion zone.

Design and Construction Cases of Preventing Ground Subsidence in Mine (광산지역 지반침하방지 설계 및 시공사례)

  • Choi, Woo-Seok;Kim, Eun-Sup;Yang, In-Jae
    • Tunnel and Underground Space
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    • v.27 no.6
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    • pp.393-405
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    • 2017
  • This report is intended to be used as a reference in the project being conducted by MIRECO for preventing ground subsidence in mining district. For this purpose, the procedure of the project for preventing ground subsidence mining district was described and cases of design, construction, and study were introduced.

A Case Study of Ground Subsidence in a Groundwater-saturated Limestone Mine (지하수로 포화된 석회석광산의 지반침하 사례연구)

  • Choi, Woo-Seok;Kim, Eun-Sup;Kang, Byung-Chun;Shin, Dong-Choon;Kim, Soo-Lo;Baek, Seung-Han
    • The Journal of Engineering Geology
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    • v.25 no.4
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    • pp.511-524
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    • 2015
  • Groundwater causing subsidence in limestone mines is uncommon, and thus relatively poorly investigated. This case study investigated the cause and possibility of future subsidence through an evaluation of ground stability at the Samsung limestone mine, Chungcheongbuk-do. The ground near the mine area was evaluated as unstable due to rainfall permeation, and subsidence in the unmined area resulted from groundwater level drawdown. Future subsidence might occur through the diffusion of subsidence resulting from the small thickness of the mined rock roof, fracture rock joints, and poor ground conditions around the mine. In addition, the risk of additional subsidence by limestone sinkage in corrosion cavities, groundwater level drawdown due to artificial pumping, and rainfall permeation in the limestone zone necessitates reinforcements and other preventative measures.

A Study on Risk Influence Factors of Ground Subsidence through Soil Investigation Analysis (지반조사 분석을 통한 지반함몰 위험영향인자 연구)

  • Joung, Ho Young;Lee, Gil Hwan
    • Journal of Korean Society of Disaster and Security
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    • v.10 no.1
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    • pp.43-46
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    • 2017
  • Recently, the development of underground space is being actively carried out in the urban area by saturation, and the excavation works are mainly carried out by various excavation methods by the structures adjacent to the ground and underground excavation. During such excavation work, ground subsidence accidents are occurring due to inattention construction, lack of construction technology, and leakage of ground water. For the prevention of ground subsidence we studied the method of risk influence factors by soil investigation. Analysis of 75 sites soil investigation by U.S.C.S (Unified Soil Classification System), construction method, depth of excavation and we studied the risk influence factors with ground subsidence.

A Study on Stress Assessment of Standing Gas Pipeline Subjected to Ground-Subsidence (지반 침하를 고려한 도시가스 입상배관의 응력평가)

  • Kil, Seong-Hee;Kim, Byung-Duk;Kwon, Jeong-Rock;Yoon, Kee-Bong
    • Journal of the Korean Institute of Gas
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    • v.17 no.2
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    • pp.1-8
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    • 2013
  • In this study, 120 cases of damage due to ground subsidence of city gas pipeline which is hanging on apartment outer wall were investigated. From the survey results, it was determined to be approximately 100m~200mm ground subsidence occurred and at severe damage, pipeline was cut and the gap was about 50mm between two cut pipeline. Device for measuring the amount of deformation of standing gas pipeline was designed and fabricated. And installed it on apartment outer wall for measuring the deformation due to ground subsidence, after 5 months measurement the amount of ground subsidence was measured to 1.3mm. Stress assessment was conducted based on results of ground subsidence occurred on standing gas pipeline.