• Title/Summary/Keyword: 트라프

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Case study of volume loss estimation during slurry tbm tunnelling in weathered zone of granite rock (화강풍화대를 통과하는 슬러리 TBM의 체적손실 산정에 대한 사례 연구)

  • Park, Hyunku;Oh, Ju-Young;Chang, Seokbue;Lee, Seungbok
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.18 no.1
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    • pp.61-74
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    • 2016
  • This paper presents a case study on the ground settlement and volume loss estimation for slurry pressure balanced shield TBM tunnelling in weathered zone of granite rock. Settlement at each stage of shield tunnelling was analyzed and the volume losses and settlement trough factors were estimated from observations. In addition, using the existing volume loss evaluation method in literature, volume losses were estimated considering ground properties and actual driving parameters. Most of ground settlement occurred during passage of shield skin passage and after backfill grouting, and the measured total volume loss and trough curves appeared to coincide with literature. Shield and tail loss obtained from field measurement were found to be around 90% and 60% of the predictions, where tail loss indicated larger deviation than shield loss.

A Study on the Fatigue Strength of a Welded Joint with Misalignment of a U-type Trough Rib in a Steel Deck Plate (강상판(鋼床版) U형(形) 트라프리브 단차용접(段差熔接)이음부(部)의 피로강도(疲勞强度)에 관(關)한 연구(硏究))

  • Lee, Dong Uk;Seo, Won Chan
    • Journal of Korean Society of Steel Construction
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    • v.8 no.3 s.28
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    • pp.13-20
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    • 1996
  • With the adoption of welded joints rather than bolted joints, we investigate the fatigue strength and the fatigue crack initiation of U-type trough rib and welded specimen with misalignment in a steel deck plate. The stress concentration factor of welded specimens with a misalignment is also verified by a finite element method. The main conclusions obtained from this study are as follows Experimental results of full-scaled U-type trough rib models have indicated that fatigue life depends on misalignments of welded joints in steel deck plate ; The more misalignments are, the less the fatigue life is. It has also shown that fatigue crack propagates from the welded root to the bead surface. We have also obtained the same results from both the fatigue test of welded specimens with a misalignment and the stress analysis of a finite element method.

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Flowrate characteristics and application of screw pump (스크류펌프의 유량특성과 적용)

  • Lim, Jong-Soon
    • 유체기계공업학회:학술대회논문집
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    • 2004.12a
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    • pp.614-625
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    • 2004
  • The main purpose of this study is to get flowrate coefficient 'q' and to study characteristics of flowrate of screw pump. This study is based on Muskin's formula and depends on the computer simulation. The results of study are as follows. 1. Flowrate coefficient will reduce according to increase of inclination. The larger the pitch ratio is and the smaller the diameter ratio is, the more coefficient reduces. 2. As a rule, the coefficient increases according to reduction of the diameter ratio, but the coefficient tends to reduce when the ratio is less than 0.45. So, in actual application, it is recommended that the ratio should be above 0.45. 3. If the pitch ratio increases, the coefficient increases in case of small inclination and decreases in case of large inclination. 4. The coefficient increases according to number of windings. Especially, singles winding is not used in actual application because it has too small coefficient. 5. The coefficient decreases when the influent water level falls. Flowrate is almost zero when the water level is below $40\%$ of Filling Points.

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Petrography and Mineral Chemistry of Some Deep Sea Basaltic Rocks from the Western Caroline Ridge and Yap Trench-Arc System (서부 캐롤라인 해령과 얍 해구-열도계의 해저 현무암질암에 대한 암석 기재 및 광물화학)

  • Park Jun-Beom;Kwon Sung-Tack;Ahn Jung-Ho;Kang Jung-Keuk
    • The Journal of the Petrological Society of Korea
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    • v.1 no.1
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    • pp.71-84
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    • 1992
  • This paper reports the results about the petrography and mineral chemistry of 13 representative dredged basaltic rocks from the western Caroline Ridge (WCR) and Yap Trench-Arc system, and provides the chemical and tectonic informations based on the compositions of clinopyroxene phenocrysts. Compositions of olivine phenocrysts in some analyzed samples are Fo$_{86-80}$. Plagioclase phenocrysts have variable compositions ranging from An$_{90}$ to An$_{55}$. The compositions of clinopyroxene phenocrysts vary according to geological environments; titansalite in atoll and guyot of WCR, diopside-augite in trough and bank of WCR, and endiopside in Yap Trench-Arc system. Application of the discrimination schemes proposed by Leterrier et al. (1982) suggests: (1) the samples from atoll-guyot belong to within plate alkali basalt, implying that western CR could be the continuation of eastern CR formed by hot spot magmatism, (2) the samples from the Yap Trench-Arc system with no present-day magmatism clearly indicate the occurrence of orogenic tholeiites presumably related to early island arc magmatisms in this area, however, (3) the samples from the bank and trough do not provide definitive informations, which might indicate the complexity of their origins.

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Estimation of Settling Efficiency in Sedimentation Basin Using Particle Tracking Method (입자추적기법을 이용한 침전지의 효율 평가)

  • Lee, Kil-Seong;Kim, Sang-Hoon
    • Journal of Korea Water Resources Association
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    • v.37 no.4
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    • pp.293-304
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    • 2004
  • Sedimentation basin plays an important role in urban water treatment, and there are many complicated phenomena which need to be understood for efficient design and control of it. Especially, the study on the improvement of settling efficiency is required. In this study, commercial CFD (Computational Fluid Dynamics) program, FLUENT, and particle tracking method were used to simulate the flow in sedimentation basin, and to predict the settling efficiency. Computational domain of real scale was made, and detail factors such as porous wall, and outlet trough were considered instead of being simplified. The simulation results were compared with the experimental data to calibrate the parameters of particle tracking method. Sensitivity analysis showed that the particle diameter had more significant effects on settling efficiency than the particle density. The computation results gave the best agreements with the experimental data, when the value of particle diameter was 26.5 ${\mu}{\textrm}{m}$.

Evaluation of the Effect of Sedimentation Basin Structure on Hydrodynamic Behavior Using CFD (II): The Effect of Trough (CFD를 이용한 침전지 구조가 수리거동에 미치는 영향 평가(II): 트라프의 영향 중심으로)

  • Park, No-Suk;Lim, Jae-Lim;Lee, Sun-Ju;Kwon, Soon-Bum;Min, Jin-Hui
    • Journal of Korean Society of Water and Wastewater
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    • v.19 no.6
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    • pp.758-766
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    • 2005
  • This study was conducted to evaluate the effect of the transverse troughs on hydrodynamic behavior within the a certain full-scale sedimentation basin (flow rate/one basin; $10,000m^3/d$) using CFD simulation and ADV technique. In order to verify the CFD simulation, we measured the factual velocity at 36 points in the full-scale sedimentation basin, whose outlet structure is inadequate, with ADV technique. Both the CFD simulation and the ADV measurement results were in good accordance with each other. From the CFD simulation results of the existing basin, it was investigated that extreme upward flow occurs in the near of two transverse troughs. It was suspected that since the transverse troughs converted the open channel flow into the local closed pipe flow, the increased pressure in this local closed pipe flow region made the extreme upward flow. For solving this problems, it was suggested to modify transverse-typed launder into finger-typed launder and to install a longitudinal baffle in the center in this study. The CFD simulation results of all suggested amendments told us that the extreme upward flow, had occurred especially in the beneath of transverse troughs, was much less in the case of finger typed launder basin than that in the existing basin. Also, it was predicted that installing a longitudinal baffle made the fully developed flow which is more effective for sedimentation.

A Study in Seismic Signal Analysis for the First Arrival Picking (초동발췌를 위한 탄성파 신호분석연구)

  • Lee, Doo-Sung
    • Geophysics and Geophysical Exploration
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    • v.10 no.2
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    • pp.131-137
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    • 2007
  • With consideration of the first arrival picking methodology and inherent errors in picking process, I propose, from the computerization point of view, a practical algorithm for picking and error computation. The proposed picking procedure consists of 2-step; 1) picking the first coherent peak or trough events, 2) derive a line which approximates the record in the interval prior to the pick, and set the intercept time of the line as the first break. The length of fitting interval used in experiment, is few samples less than 1/4 width of the arriving wavelet. A quantitative measure of the error involved in first arrival picking is defined as the time length that needed to determine if an event is the first arrival or not. The time length is expressed as a function of frequency bandwidth of the signal and the S/N ratio. For 3 sets of cross-well seismic data, first breaks are picked twice, by manually, and by the proposed method. And at the same time, the error bound for each trace is computed. Experiment results show that good performance of the proposed picking method, and the usefulness of the quantitative error measure in pick-quality evaluation.

Development of a Neural Network Expert System for Safety Analysis of Structures Adjacent to Tunnel Excavation Sites Focused on Development and Reliability Evaluation of Expert System (터널굴착 현장에 인접한 지상구조물의 안전성 평가용 전문가 시스템의 개발 (1) -전문가 시스템 개발 및 신뢰성 검증을 중심으로)

  • 배규진;신휴성
    • Geotechnical Engineering
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    • v.14 no.2
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    • pp.107-126
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    • 1998
  • Ground settlements induced by tunnel excavation cause the foundations of the neighboring building structures to deform. An expert system called NESASS( Neural network Expert System for Adjacent Structure Safety analysis) was developed to analyze the structural safety of such building structures. NESASS predicts the trend of ground settlements resulting from tunnel excavation and carries out a safety analysis for building structures on the basis of the predicted ground settlements. Using neural network technique. the NESASS learns the database consisting of the measured ground settlements collected from numerous actual fields and infers a settlement trend at the field of interest. The NESASS calculates the magnitudes of angular distortion, deflection ratio, and differential settlement of the structure. and in turn, determines the safety of the structure. In addition, the NESASS predicts the patterns of cracks to be formed in the structure, using Dulacska model for crack evaluation. In this study, the ground settlements measured from Seoul subway construction sites were collected and classified with respect to the major factors influencing ground settlement. Subsequently, a database of ground settlement due to tunnel excavation was built. A parametric study was performed to select the optimal neural network model for the database. A comparison of the ground settlement predicted by the NESASS with the measured ones indicates that the NESASS leads to reasonable predictions. The results of confidence evaluation for safety evaluation system of the NESASS are presented in this paper.

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Damage Assessment of Adjacent Structures due to Tunnel Excavation in Urban Areas (II) - Focused on the Variations of Building Stiffness Ratio - (도심지 터널 굴착에 따른 인접구조물의 손상평가에 관한 연구 (II) - 지상 건물의 강성비 변화를 중심으로 -)

  • 김창용;배규진;문현구;박치현;오명렬
    • Journal of the Korean Geotechnical Society
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    • v.15 no.5
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    • pp.81-98
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    • 1999
  • The influence of tunnelling on buildings has become an important issue in urban areas. The problem is an interactive one: not only do tunnelling settlements affect existing structures, but existing structures affect tunnel-induced soil movements. In order to examine the constraint of surface settlement and the degradation of building damage parameters, 3-dimensional elasto-plastic finite element analyses are peformed. Also, in this paper, the results of the parametric studies for the variations of the damage parameters due to the ground movements are presented by utilizing 2-dimensional elasto-plastic finite element models, totally 162 models. The width of a structure, its bending and axial stiffness, its position relative to the tunnel and the depth of tunnel are considered. The interaction is shown by reference to commonly-used building damage parameters, namely angular distortion, deflection ratio, maximum building settlements, maximum differential settlements and horizontal strain. By introducing relative stiffness parameters which combine the bending and axial stiffness of the structure with its width and stiffness of soil, design curves are established. These give a guide as to the likely modification of the greenfield settlement trough caused by a surface structure. They can be used to give initial estimates of likely building damage.

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