• Title/Summary/Keyword: Construction Failure

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Investigation of slope reinforcement with drilled shafts in colluvium soils

  • Lia, An-Jui;Wang, Wei-Chien;Lin, Horn-Da
    • Geomechanics and Engineering
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    • v.31 no.1
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    • pp.71-86
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    • 2022
  • In Taiwan, an efficient approach for enhancing the stability of colluvium slopes is the drilled shaft method. For slopes with drilled shafts, the soil arching effect is one of the primary factors influencing slope stability and intertwines to the failure mechanism of the pile-soil system. In this study, the contribution of soil arching effect to slope stability is evaluated using the FEM software (Plaxis 3D) with the built-in strength reduction technique. The result indicates the depth of the failure surface is influenced by the S/D ratio (the distance to the diameter of piles), which can reflect the contribution of the soil arching effect to soil stability. When α (rock inclination angles)=β (slope angles) is considered and the S/D ratio=4, the failure surface of the slope is not significantly influenced by the piles. Overall, the soil arching effect is more significant on α=β, especially for the steep slopes. Additionally, the soil arching effect has been included in the proposed stability charts. The proposed charts were validated through two case studies, including that of the well-known Woo-Wan-Chai field in Taiwan. The differences in safety factor (FoS) values between the referenced literature and this study was approximately 4.9%.

Limit analysis of a shallow subway tunnel with staged construction

  • Yu, Shengbing
    • Geomechanics and Engineering
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    • v.15 no.5
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    • pp.1039-1046
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    • 2018
  • This paper presents a limit analysis of the series of construction stages of shallow tunneling method by investigating their respective safety factors and failure mechanisms. A case study for one particular cross-section of Beijing Subway Line 7 is undertaken, with a focus on the effects of multiple soil layers and construction sequencing of dual tunnels. Results show that using the step-excavation technique can render a higher safety factor for the excavation of a tunnel compared to the entire cross-section being excavated all at once. The failure mechanisms for each different construction stage are discussed and corresponding key locations are suggested to monitor the safety during tunneling. Simultaneous excavation of dual tunnels in the same cross-section should be expressly avoided considering their potential negative interactions. The normal and shear forces as well as bending moment of the primary lining and locking anchor pipe are found to reach their maximum value at Stage 6, before closure of the primary lining. Designing these struts should consider the effects of different construction stages of shallow tunneling method.

Development of AI-Based Condition Monitoring System for Failure Diagnosis of Excavator's Travel Device (굴착기 주행디바이스의 고장 진단을 위한 AI기반 상태 모니터링 시스템 개발)

  • Baek, Hee Seung;Shin, Jong Ho;Kim, Seong Joon
    • Journal of Drive and Control
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    • v.18 no.1
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    • pp.24-30
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    • 2021
  • There is an increasing interest in condition-based maintenance for the prevention of economic loss due to failure. Moreover, immense research is being carried out in related technologies in the field of construction machinery. In particular, data-based failure diagnosis methods that employ AI (machine & deep learning) algorithms are in the spotlight. In this study, we have focused on the failure diagnosis and mode classification of reduction gear of excavator's travel device by using the AI algorithm. In addition, a remote monitoring system has been developed that can monitor the status of the reduction gear by using the developed diagnosis algorithm. The failure diagnosis algorithm was performed in the process of data acquisition of normal and abnormal under various operating conditions, data processing and analysis by the wavelet transformation, and learning. The developed algorithm was verified based on three-evaluation conditions. Finally, we have built a system that can check the status of the reduction gear of travel devices on the web using the Edge platform, which is embedded with the failure diagnosis algorithm and cloud.

Disaster Risk Assessment by Work Unit of Construction Work for Improve the Efficiency of Design for Safety Task (설계의 안전성 검토(DFS) 업무의 효율성 증대를 위한 공동주택 건설공사의 단위작업별 재해위험성 평가)

  • Kim, Jin-Won;Kim, Jae-Jun
    • Journal of the Architectural Institute of Korea Structure & Construction
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    • v.34 no.6
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    • pp.45-53
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    • 2018
  • The construction work to establish a safety management plan should be carried out Design for Safety(DFS) task by the designers from May 2016 according to the amendment of the Construction Technology Promotion Act. However, designers lack experience in construction work and lack of information on safety accidents, so it is not easy to predict a disaster that may occur during the construction phase. Therefore, the purpose of this study is to provide information about disasters that can occur in each construction work in order to enable designers to efficiently perform DFS task in the design phase. In this study, the construction work was classified by work unit and the disaster risk assessment was conducted using the Failure Mode and Effect Analysis technique. The disaster information by work unit analyzed in this study can be used to provide designers with an alternative to prevent disasters at the design stage. Disaster information by work unit of apartment construction can be used by designers to prepare an alternative for disaster prevention at the design stage.

A Study on Life Prediction of Hydraulic Piston Pump (유압 피스톤 펌프의 수명 예측 연구)

  • Kim, Kyungsoo;Lee, Jihwan;Kang, Myeongcheol;Ryuh, Beomsahng
    • Journal of the Korea Institute of Military Science and Technology
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    • v.21 no.5
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    • pp.607-613
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    • 2018
  • Hydraulic systems are widely used in the field of defense, construction machinery, agricultural machinery, and general industries, due to various advantages such as quick response speed and precision control. The defense equipments such as light rescue vehicle is operated in very harsh environments, so hydraulic components used in defense equipment are required to have very high reliability. In particular, hydraulic piston pump is very important component in a hydraulic systems, so life prediction of pump is essential. Therefore, in this study, we analyze the potential failure and the main failure mode of the hydraulic piston pump for the light rescue vehicle through the FMEA analysis, and predict the life of the pump by the accelerated life test considering the usage conditions.

A Consideration about Stability Investigation method of Failure Cut-Slope Covered by Vegetation (식생공이 시공된 붕괴절토사면의 안정성 검토기법에 관한 고찰)

  • Yoo, Ki-Jeong;Koo, Ho-Bon;Rhee, Jong-Hyun;Kim, Seung-Hyun
    • Proceedings of the Korean Geotechical Society Conference
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    • 2005.03a
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    • pp.725-730
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    • 2005
  • In case of the national roads which is opened in the past, there are carried out the expansion and improvement for enlargement of the traffic demand by industrial development and safety road operation to narrow of road width and serious change of the road alignment with effect of topography and graphical features of a mountain. A protection method using vegetation in the cut-slope has been constructed for harmony of ambient environment after cutting the slope recently. But it requires a study because the surface lose and the failure have been occurred in the large cut-slope which is covered by vegetation. In this study it was presented a countermeasure and examined a stability of contained uncertainty in the cut-slope according to the failure example of the cut-slope which is covered by vegetation. The additional research will be necessary against the development of the investigation technique which executes the stability investigation of the cut-slope which is covered by vegetation.

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Slope stability associated with construction (건설공사와 사면 안정성)

  • Baek, Yong;Kim, Gyo-Won;Koo, Ho-Bon
    • The Journal of Engineering Geology
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    • v.10 no.2
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    • pp.1-17
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    • 2000
  • In this study, 270 cut-slopes are investigated and statistical analyses are performed. More than 84% of unstable slopes are rock slopes or rock-soil mixed slopes, and 72% of the slopes have 10 to 30 meter in height. And in order to clarify the cause of failure, 3 slopes which have been failed are back-analysed by using the computer programs such as DIPS, UDEC and PCSTABL5M. A heavy rainfall during rainy season is a main cause of slope failure, and a blasting vibration during construction could also give a significant influence on the slope instability.

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A Study on the Risk Evaluation using Acoustic Emission in Rock Slope (암반 비탈면에서 AE 기법을 이용한 위험도 평가 연구)

  • Byun, Yoseph;Kim, Sukchun;Seong, Joohyun;Chun, Byungsik;Jung, Hyuksang
    • Journal of the Korean GEO-environmental Society
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    • v.15 no.11
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    • pp.5-12
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    • 2014
  • A slope may fail after construction owing to external factors such as localized rainfall, earthquake, and weathering. Therefore, the grasp of failure probability for slope failures is necessary to maintain their stability. In particular, it is very difficult to detect the symptoms of rock slope failure in advance by using traditional methods, such as displacement due to the brittleness of rocks. However, Acoustic Emission (AE) techniques can predict slope failures earlier than the traditional methods. This study grasped failure probability of slope by applying AE techniques to a rock slope with a history of collapse. When applying AE techniques to a slope that has a high probability of failure, the grasp of failure probability of the specific location became possible.

A Study on the Stability Evaluation and Numerical Simulation of Toppling Failure on a Cut-Slope (절토사면의 전도파괴에 대한 안정성 평가 및 수치해석적 고찰)

  • Choi, Ji-Yong;Kim, Seung-Hyun;Koo, Ho-Bon
    • The Journal of Engineering Geology
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    • v.20 no.1
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    • pp.13-23
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    • 2010
  • Toppling failure of a slope is defined as failure behavior accompanying the rotation of rock block which is different from other failure such as sliding along with discontinuities and so on. It generally occurs in the region that discontinuities were developed with inverse dip direction to a slope and it could play a critical role in judging stability of slope. In this study, the stability evaluation was performed about toppling failure on a jointed road cut-slope. To check the deformation behavior, numerical analysis is widely used. However common analysis programs are based on continuum model. Recently, many methods that discontinuity properties can be considered in continuum analysis are suggested. In this study, numerical analysis based on FEM(Finite Element Method) was performed using interface element applied in heterogeneous boundary to simulate effects of discontinuities.

Dynamic nonlinear member failure propagation in truss structures

  • Malla, Ramesh B.;Nalluri, Butchi B.
    • Structural Engineering and Mechanics
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    • v.9 no.2
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    • pp.111-126
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    • 2000
  • Truss type structures are attractive to a variety of engineering applications on earth as well as in space due to their high stiffness to mass ratios and ease of construction and fabrication. During the service life, an individual member of a truss structure may lose load carrying capacity due to many reasons, which may lead to collapse of the structure. An analytical and computational procedure has been developed to study the response of truss structures subject to member failure under static and dynamic loadings. Emphasis is given to the dynamic effects of member failure and the propagation of local damage to other parts of the structure. The methodology developed is based on nonlinear finite element analysis technique and considers elasto-plastic material nonlinearity, postbuckling of members, and large deformation geometric nonlinearity. The pseudo force approach is used to represent the member failure. Results obtained for a planar nine-bay indeterminate truss undergoing sequential member failure show that failure of one member can initiate failure of several members in the structure.