• Title/Summary/Keyword: 암반절리

Search Result 514, Processing Time 0.023 seconds

Modification of the Cubic law for a Sinusoidal Aperture using Perturbation Approximation of the Steady-state Navier-Stokes Equations (섭동 이론을 이용한 정상류 Navier-Stokes 방정식의 주기함수 간극에 대한 삼승 법칙의 수정)

  • 이승도
    • Tunnel and Underground Space
    • /
    • v.13 no.5
    • /
    • pp.389-396
    • /
    • 2003
  • It is shown that the cubic law can be modified regarding the steady-state Navier-Stokes equations by using perturbation approximation method for a sinusoidal aperture variation. In order to adopt the perturbation theory, the sinusoidal function needs to be non-dimensionalized for the amplitude and wavelength. Then, the steady-state Navier-Stokes equations can be solved by expanding the non-dimensionalized stream function with respect to the small value of the parameter (the ratio of the mean aperture to the wavelength), together with the continuity equation. From the approximate solution of the Navier-Stokes equations, the basic cubic law is successfully modified for the steady-state condition and a sinusoidal aperture variation. A finite difference method is adopted to calculate the pressure within a fracture model, and the results of numerical experiments show the accuracy and applicability of the modified cubic law. As a result, it is noted that the modified cubic law, suggested in this study, will be used for the analysis of fluid flow through aperture geometry of sinusoidal distributions.

The Water Environment at the Seokdae Waste Landfill Area in the Pusan Metropolitan City (부산 석대 폐기물 매립지 일원의 수질 환경)

  • 정상용;권해우;이강근;김윤영
    • Journal of the Korean Society of Groundwater Environment
    • /
    • v.4 no.4
    • /
    • pp.175-184
    • /
    • 1997
  • The Seokdae Waste Landfill is a middle-sized site used from June, 1987 to May, 1993. Many joints and faults are developed in andesitic rocks and rhyolitic rocks distributed at the landfill. The chemical analyses of leachates, streams and groundwaters sampled in July, 1996 and June, 1997 show that the concentrations of leachates and streams were decreased, and that the groundwater qualities became worse. The groundwater contamination is deeply extended to not only shallow groundwater but also bedrock-groundwater around the Seokdae Waste Landfill Area. The range of groundwater contamination by the leachates is about 500 m to the west and about 1 km to the south from the boundaries of the waste landfill. The development of monitoring wells and pumping wells, the construction of a leachate-treatment facilities, and the adjustment of the existing grout curtains are necessary for the control of water pollution at the Seokdae Waste Landfill Area.

  • PDF

Evaluation on the leakage of ground-water through fractured rock under a spillway (여수로 구조물 하부 암반 내 발달한 절리들을 통한 지하수 누수량 분석)

  • Kim, Hyoung-Soo;Lee, Ju-Hyun;Jeong, Ui-Jin;Lee, Joong-Woo
    • Proceedings of the Korean Geotechical Society Conference
    • /
    • 2006.03a
    • /
    • pp.69-74
    • /
    • 2006
  • Recently, spillways are need to control stable water level for supporting main dams because of floods by unusual change of weather such as Typhoon Rusa. This study has been focused on the amount of leakage through the rock mass distributed fractures and joints under the opened emergency spillway. It is very important to evaluate the amount of leakage as these affect stability of spillway by interaction between effective stress and pore pressure. The commercial program MAFIC has been used for analyzing groundwater flow in fractured rock mass. The results showed that the values of range, average and deviation of leakage were $2.85\sim\;3.79\times10^{-1}$, $3.32\times10^{-1}$ and $1.70\times10^{-2}\;m^3/day/m^2$ respectively. Secondary, we have estimated the effect of grouting after the transmissivity$(T_f)$ of joint 1 as main pathway of leakage known from above results was changed from $1.78\times10^{-7}$ to $1.59\times10^{-9}\;m^2/s$. The results showed that the values of range, average and deviation of leakage were $7.80\times10^{-4}\sim1.53\times10^{-3}$, $1.18\times10^{-3}$ and $1.32\times10^{-4}\;m^3/day/m^2$ respectively. As the result, the amount of leakage after grouting has been decreased by a ratio of 1 to 277.

  • PDF

A Study of Theoretical Method and Application to Laboratory Tests for Three-dimensional Transient Seepage Analysis (삼차원(三次元) 침투류해석(浸透流解析)을 위한 이론적(理論的) 방법(方法)과 실험적용예(實驗適用例)에 관(關)한 고찰(考察))

  • Jin, Byung Ik;Kim, Jae Hong
    • KSCE Journal of Civil and Environmental Engineering Research
    • /
    • v.4 no.2
    • /
    • pp.13-24
    • /
    • 1984
  • The main part of this thesis deals with a three-dimensional transient seepage flow, discussing its fundamental conception into Which the mathematical analysis was introduced based upon the finite element method, propriety of geometrical analysis and flow movement of seepage water. As is commented in the body of the report, the saturated-unsaturated method with respect to the free water surface method is revealed to have the relative merits and demerits. Generally, the unknown sections in the form of free water surface matters in case that tunnels or pores appear. On the other hand, the applicable range is quite large and variable to the methods accordingly. Also, an example as to the seepage analysis in the rock bed section is described. An unfavorable time-consuming problem is inevitale because the complicated and widely multifarious joints and faults are responsible for the intensity of seepage flow.

  • PDF

An Analysis on the Deformation of Foundation Using the Interface Element Method (접합요소(接合要素)를 이용(利用)한 기초지반(基礎地盤)의 변형해석(變形解析))

  • Park, Byong Kee;Lee, Jean Soo;Lim, Sung Chull
    • KSCE Journal of Civil and Environmental Engineering Research
    • /
    • v.10 no.1
    • /
    • pp.155-162
    • /
    • 1990
  • In analysis of deformation in which the stiffness is greatly different between the adjacent materials, the desired results have been obtained by using the interface element method compared with those secured by the conventional method of the concept of continua. However the interface element method was originally developed for the behavior of rocks. This study deals with the deformation analysis of foundation with sand drain by the introduction of interface element. The physical conditions of interface element are devided into three categories by Mohr-Coulomb failure criterion ie. sliding, separation, and contact. Finally the accuracy of the program proposed in this paper is proved highly accurate by performing the comparison of the theoretical values and numerical results of a model element with simplified boundary conditions.

  • PDF

A Study on Applicability of Equivalent Continuum Flow Model in DFN Media (DFN 매질에 대한 등가연속체 유동모델의 적용 가능성 평가에 관한 연구)

  • Lee, Dahye;Um, Jeong-Gi
    • Tunnel and Underground Space
    • /
    • v.27 no.5
    • /
    • pp.303-311
    • /
    • 2017
  • The correlation analysis between the results obtained from DFN flow model and equivalent continuum flow model were conducted on total of 72 DFN blocks having various fracture geometry and domain size. A strong linear relation seems to exist between the two approaches under condition that normalized relative error for continuum behavior (ER) is less than 0.2, and the results from both methods are found to almost identical. To explore the field applicability of equivalent continuum flow model in DFN media, a total of 48 numerical schemes related to inflow of underground circular openings were implemented under various DFN configurations. The equivalent continuum flow model in DFN media with a constant hydraulic aperture was evaluated as valid. However, as the anisotropy increases due to variation of the hydraulic aperture, the results are likely to be overestimated compare to the DFN flow model.

Evaluation of tunnel face stability based on upper bound theorem (상한치 이론에 근거한 터널 막장의 안정성 연구)

  • Lee, In-Mo;Lee, Jae-Sung;Nam, Seok-Woo
    • Journal of Korean Tunnelling and Underground Space Association
    • /
    • v.5 no.1
    • /
    • pp.3-11
    • /
    • 2003
  • Face stability of a tunnel is a main concern during tunnel excavation. However, there has been only a few studies on this problem while a lot of researches on the support systems have been carried out. In addition, when tunneling is performed below the groundwater level, the groundwater flows into the tunnel so that the seepage forces generated on the tunnel face might give rise to a serious potential for the face instability. In this study, the face stability was evaluated by simultaneously considering two factors: one is the effective stress calculated by upper bound theorem; the other is the seepage forces acting on the tunnel face obtained by numerical analysis under the condition of steady-state groundwater flow. Tunneling in difficult geological conditions often requires auxiliary techniques to guarantee safe tunnel excavations and/or to prevent damage to structures and services around the tunnel. The steel pipe-reinforced multistep grouting has been recently applied to tunnel sites in Korea. Face stability of a tunnel with the steel pipe-reinforced multistep grouting was also analyzed in this study.

  • PDF

A Case Study of Prediction and Analysis of Unplanned Dilution in an Underground Stoping Mine using Artificial Neural Network (인공신경망을 이용한 지하채광 확정선외 혼입 예측과 분석 사례연구)

  • Jang, Hyongdoo;Yang, Hyung-Sik
    • Tunnel and Underground Space
    • /
    • v.24 no.4
    • /
    • pp.282-288
    • /
    • 2014
  • Stoping method has been acknowledged as one of the typical metalliferous underground mining methods. Notwithstanding with the popularity of the method, the majority of stoping mines are suffering from excessive unplanned dilution which often becomes as the main cause of mine closure. Thus a reliable unplanned dilution management system is imperatively needed. In this study, reliable unplanned dilution prediction system is introduced by adopting artificial neural network (ANN) based on data investigated from one underground stoping mine in Western Australia. In addition, contributions of input parameters were analysed by connection weight algorithm (CWA). To validate the reliability of the proposed ANN, correlation coefficient (R) was calculated in the training and test stage which shown relatively high correlation of 0.9641 in training and 0.7933 in test stage. As results of CWA application, BHL (Length of blast hole) and SFJ (Safety factor of Joint orientation) show comparatively high contribution of 18.78% and 19.77% which imply that these are somewhat critical influential parameter of unplanned dilution.

Assessment of Blast-induced Vibration Using Dynamic Distinct Element Analysis (불연속체 동해석 기법을 이용한 발파진동 영향평가)

  • Park, Byung-Ki;Jeon, Seokwon;Park, Gwang-Jun;Do, Deog-Soo;Kim, Tae-Hoon;Jung, Du-Seop
    • Transactions of the Korean Society for Noise and Vibration Engineering
    • /
    • v.15 no.12 s.105
    • /
    • pp.1389-1397
    • /
    • 2005
  • Since blast-induced vibration may cause serious problem to the rock mass as well as the nearby structures, the prediction of blast-induced nitration and the stability evaluation must be performed before blasting activities. Dynamic analysis has been increased recently in order to analyze the effect of the blast-Induced vibration. Most of the previous studies, however, were based on the continuum analysis unable to consider rock joints which significantly affect the wave propagation and attenuation characteristics. They also adopted pressure corves estimated tv theoretical or empirical equations as input detonation load, thus there were very difficult to reflect the characteristics of propagating media. In this study, therefore, we suggested a dynamic distinct element analysis technique which uses velocity waveform obtained from a test blast as an input detonation load. A distinct element program, UDEC was used to consider the effect of rock joints. In order to verify the validity of proposed method, the test blast was simulated. The predicted results from the proposed method showed a good agreement with the measured vibration data from the test blast. Through the dynamic numerical modelling on the planned road tunnel and slope, we evaluated the effect of blast-induced nitration and the stability of rock slope.

Study on Establishing a Blast Guideline for Securing an Underground Crusher Room from Ground Vibrations (지하 조쇄실의 진동 안정성 확보를 위한 발파지침 수립 연구)

  • Choi, Byung-Hee;Ryu, Chang-Ha;Kim, Hyun-Woo;Kang, Myoung-Soo
    • Explosives and Blasting
    • /
    • v.33 no.2
    • /
    • pp.15-24
    • /
    • 2015
  • In general, blast vibrations could make underground cavern unstable by causing relative movements between the surrounding rock blocks that are divided by discontinuities such as joints and faults around the cavern. In the study, a blast guideline was established to obtain the stability of a large-scale cavern for underground crusher room in an open pit limestone mine in Korea. The guideline was suggested in the form of a standard calculation method of the maximum charge per delay for a safe blast. The allowable level of peak particle velocity for the cavern was determined based on the result of a numerical analysis using FLAC2D. The ground vibration data required for the study was obtained from field measurements.