• Title/Summary/Keyword: rock blasting

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Prediction of Disk Cutter Wear Considering Ground Conditions and TBM Operation Parameters (지반 조건과 TBM 운영 파라미터를 고려한 디스크 커터 마모 예측)

  • Yunseong Kang;Tae Young Ko
    • Tunnel and Underground Space
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    • v.34 no.2
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    • pp.143-153
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    • 2024
  • Tunnel Boring Machine (TBM) method is a tunnel excavation method that produces lower levels of noise and vibration during excavation compared to drilling and blasting methods, and it offers higher stability. It is increasingly being applied to tunnel projects worldwide. The disc cutter is an excavation tool mounted on the cutterhead of a TBM, which constantly interacts with the ground at the tunnel face, inevitably leading to wear. In this study quantitatively predicted disc cutter wear using geological conditions, TBM operational parameters, and machine learning algorithms. Among the input variables for predicting disc cutter wear, the Uniaxial Compressive Strength (UCS) is considerably limited compared to machine and wear data, so the UCS estimation for the entire section was first conducted using TBM machine data, and then the prediction of the Coefficient of Wearing rate(CW) was performed with the completed data. Comparing the performance of CW prediction models, the XGBoost model showed the highest performance, and SHapley Additive exPlanation (SHAP) analysis was conducted to interpret the complex prediction model.

The Application of Copper Smelting Slag as Concrete aggregate (콘크리트용 동슬래그 골재의 활용 기술)

  • Ji, Seok-Won;Seo, Chee-Ho
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.2 no.2
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    • pp.68-75
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    • 2006
  • The total production of the smelted copper reaches 450,000 tons per year, and the production of copper-related goods grows year by year owing to the extension of facilities and the development of production techniques. On the other hand, the volume of slag discharges by-produced at the time of copper smelting process is also on trend of increase. The by-produced copper smelting slag amounts to 700,000 tons a year, which is one and half times of the total smelted copper production. Accordingly nobody disagrees that comprehensive researches on how to deal with and how to reuse the accumulated smelting copper slag have to be encouraged. Even though the possible uses of the copper smelting slag have being made on various levels at present as materials for iron powder cement, sand-blasting and fire-proofing rock wool, but a considerable volume of the slag is abandoned as unnecessary by burying or piling up in careless in the open ground.

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The Ancient Construction Materials and Methods: The Great Wall of China in Jinshanling as a Case Study

  • Yang, Jin;Tan, Fabian Hadipriono;Tan, Adrian
    • Journal of Construction Engineering and Project Management
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    • v.7 no.1
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    • pp.37-49
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    • 2017
  • The Jinshanling section of the Great Wall of China is a series of fortifications in northern China that was constructed for strategic military defenses. This section was first built in the beginning of the Ming Dynasty in AD 1368 and then underwent major construction, reconstruction and renovation during the late Ming Dynasty, approximately in AD 1569. The Jinshanling section is 10.5 km long, a very short section compared with the entire 21,200 km wall. The wall section is located in Luanping County, Hebei province, China. This research paper focuses on the construction methods and materials of the wall and the towers in the area. The research methodology includes site visits, knowledge acquisition of experts and 3D graphic modeling. This study reveals that the materials selected for the structure include rubbles and rammed earth, bricks, stones, timber, and mortar. The erection sequence of the wall and the towers was a bottom-up fashion using various ancient construction techniques, such as the fire-setting rock blasting techniques and the surveying techniques from the Sea Island Mathematical Manual.

A Study on the Geotechnical Characteristics of Tunnel Collapse (국내외 터널 붕락의 지반공학적 특징에 관한 연구)

  • Seo, Kyoungwon;Kim, Woongku;Baek, Kihyun
    • Journal of Korean Society of societal Security
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    • v.2 no.4
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    • pp.75-81
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    • 2009
  • This paper presents the geotechnical characteristics of tunnel co \l apse based on the case studies. For domestic cases, most collapses are likely to happen along the weakest zone of shear strength due to the change of stresses induced by excavation specially when soft or weathered rock exist in front of a tunnel. In other words, the collapse of a tunnel occurs along the highly weathered fractured zone due to blasting and excavation. In Europe, collapses have been occurred by one joint group even though the ground is relatively fresh and for the rocks of which RQD is over 50%. In addition, the amount of ground water flow does not seem to be seriously affected by the RQD range.

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A example study on monitoring near field vibration in the rock mass adjacent blast hole (발파공 주변의 인접거리 진동계측 사례연구)

  • Lee, Hyo;Won, Yeon-Ho;Kim, Jin-Soo;Ju, Young-Og
    • Proceedings of the KSEE Conference
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    • 2006.10a
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    • pp.153-166
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    • 2006
  • 종래의 발파진동의 분석은 주로 대상 지장물에 대한 피해한계를 정립시키고자 하는 관점에서 발파공에서 비교적 원거리의 진동특성을 이해하기 위해 수행되어져 왔으나, 최근의 추이는 발파공 주변 암반의 손상의 정도를 평가하고자 하는 관점에서 그 분석영역의 범위가 근거리 진동특성 연구분야로 확대되고 있는 실정이다. 특히, 터널 발파작업시 여굴의 발생, 암반사면의 안정성 검토 등의 목적으로 암반의 손상영역을 평가하는데 있어서, 기초자료로 활용하고자 많은 연구가 이루어지고 있다. 암반손상의 평가를 위한 손상권 예측방법에는 여러 가지가 있으나, 그 중에서 대부분이 발파진동속도에 근거하고 있으며, 평가를 위한 진동의 예측은 기존에는 원거리 진동특성을 이용하여 근거리 진동을 예측하는 방법으로 그 손상의 정도를 평가하였으나, 최근의 추세는 계측기의 발달로 수m 이내의 진동특성의 계측이 가능하게 되었다. 이와 관련하여 국외에서는 수차례의 실험결과가 여러 문헌에서 보고되고 있으나, 실험장비의 선택 및 측정방법의 어려움 등의 연유로 국내에서는 아직까지 실시되지 못하고 있는 상황이다. 따라서, 본 연구에서는 실제 발파공 근접진동(near field vibration) 계측을 실시하고 그 결과를 분석하여 추후 지속적인 근거리 진동측정 방법 및 평가방법에 대한 기초자료를 제공하고자 하였으며, 무엇보다도 어떻게 계측할 것인가 하는 계측방법 및 그 계측결과의 분석방법에 대해 문제점 파악 및 향후 보완점에 대해 비중을 두어 수행하였다.

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Three-Dimensional Dynamic Analysis of Underground Openings Subjected to Explosive Loadings (폭발하중에 대한 지하공동구조체의 3차원 공적 유한요소해석)

  • 김선훈;김진웅;김광진
    • Computational Structural Engineering
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    • v.10 no.2
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    • pp.171-178
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    • 1997
  • Three-dimensional dynamic analyses of underground openings subjected to explosive loadings are carried out. Dynamic analyses consist of two steps; one-dimensional source calculation and three-dimensional tunnel analysis. One-dimensional source calculation includes explosive charge and the free field surrounding rock. The input pressure time history for three-dimensional tunnel analysis is obtained from the companion one-dimensional source calculation. The computer program MPDAP-3D incorporated this analysis capability. It is shown that the computer program is a useful tool for the analysis of the structural safety evaluation of underground openings during construction by drill and blasting method.

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Stemming Effect of the Crushed Granite Sand as Fine Aggregate at the Mortar Blasting Test (화강암 부순모래의 발파전색효과 연구)

  • Kim, Hak-Sung;Lee, Sang-Eun
    • Tunnel and Underground Space
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    • v.21 no.4
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    • pp.320-327
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    • 2011
  • In this study, for stemming effect in blast of the mortar block body, the crushed granite sand as fine aggregate, which is waste rock obtained at the ○○ limestone mine, was investigated to compare with stemming materials such as sea sand, river sand, clayed soil and water can be acquired easily at the field. The mortar block body was manufactured with the dimensions of 50 cm width, 50 cm length and 70 cm height. The direct shear and sieve separator test were performed, and the properties of friction resistance were analyzed by the extrusion test for five stemming materials. Axial strain of steel bar and ejection velocity of stemming materials due to the explosive shock pressure in blasthole with the stemming length of 10 cm and 20 cm in the mortar blast test were measured by the dynamic data acquisition system. Among stemming materials, axial strain showed the largest value at the crushed granite sand as fine aggregate, and the ejection velocity was the smallest value at the stemming of water. The results has shown correlate with harden unit weight in blasthole, particle size distribution, shear resistance, and extrusion strength of stemming materials. The ejection velocity of stemming material at the mouth of blasthole and the axial strain of steel bar in the inside of blasthole tend to be inversely proportional to each other, represent exponentially.

Dynamical Study on the Blasting with One-Free-Face to Utilize AN-FO Explosives (초유폭약류(硝油爆藥類)를 활용(活用)한 단일자유면발파(單一自由面發破)의 역학적(力學的) 연구(硏究))

  • Huh, Ginn
    • Economic and Environmental Geology
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    • v.5 no.4
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    • pp.187-209
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    • 1972
  • Drilling position is one of the most important factors affecting on the blasting effects. There has been many reports on several blasting factors of burn-cut by Messrs. Brown and Cook, but in this study the author tried to compare drilling positions of burn-cut to pyramid-cut, and also to correlate burn-cut effects of drilling patterns, not being dealt by Prof. Ito in his theory, which emphasized on dynamical stress analysis between explosion and free face. According to former theories, there break out additional tensile stress reflected at the free face supplemented to primary compressive stress on the blasting with one-free-face. But with these experimented new drilling patterns of burn-cut, more free faces and nearer distance of each drilling holes make blasting effects greater than any other methods. To promote the above explosive effect rationary, it has to be considered two important categories under-mentioned. First, unloaded hole in the key holes should be drilled in wider diameter possibly so that it breaks out greater stress relief. Second, key holes possibly should have closer distances each other to result clean blasting. These two important factors derived from experiments with, theories of that the larger the dia of the unloaded hole, it can be allowed wider secondary free faces and closes distances of each holes make more developed stress relief, between loaded and unloaded holes. It was suggested that most ideal distance between holes is about 4 clearance in U. S. A., but the author, according to the experiments, it results that the less distance allow, the more effective blasting with increased broken rock volume and longer drifted length can be accomplished. Developed large hole burn-cut method aimed to increase drifting length technically under the above considerations, and progressive success resulted to achieve maximum 7 blasting cycles per day with 3.1m drifting length per cycle. This achievement originated high-speed-drifting works, and it was also proven that application of Metallic AN-FO on large hole burn-cut method overcomes resistance of one-free-face. AN-FO which was favored with low price and safety handling is the mixture of the fertilizer or industrial Ammonium-Nitrate and fuel oil, and it is also experienced that it shows insensible property before the initiation, but once it is initiated by the booster, it has equal explosive power of Ammonium Nitrate Explosives (ANE). There was many reports about AN-FO. On AN-FO mixing ratio, according to these experiments, prowdered AN-FO, 93.5 : 6.5 and prilled AN-FO 94 : 6, are the best ratios. Detonation, shock, and friction sensities are all more insensitive than any other explosives. Residual gas is not toxic, too. On initation and propagation of the detonation test, prilled AN-FO is more effective than powered AN-FO. AN-FO has the best explosion power at 7 days elapsed after it has mixed. While AN-FO was used at open pit in past years prior to other conditions, the author developed new improved explosives, Metallic AN-FO and Underwater explosive, based on the experiments of these fundmental characteristics by study on its usage utilizing AN-FO. Metallic AN-FO is the mixture of AN-FO and Al, Fe-Si powder, and Underwater explosive is made from usual explosive and AN-FO. The explanations about them are described in the other paper. In this study, it is confirmed that the blasting effects of utilizing AN-FO explosives are very good.

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Reformability evaluation of blasting-enhanced permeability in in situ leaching mining of low-permeability sandstone-type uranium deposits

  • Wei Wang;Xuanyu Liang;Qinghe Niu;Qizhi Wang;Jinyi Zhuo;Xuebin Su;Genmao Zhou;Lixin Zhao;Wei Yuan;Jiangfang Chang;Yongxiang Zheng;Jienan Pan;Zhenzhi Wang;Zhongmin Ji
    • Nuclear Engineering and Technology
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    • v.55 no.8
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    • pp.2773-2784
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    • 2023
  • It is essential to evaluate the blasting-enhanced permeability (BEP) feasibility of a low-permeability sandstone-type uranium deposit. In this work, the mineral composition, reservoir physical properties and rock mechanical properties of samples from sandstone-type uranium deposits were first measured. Then, the reformability evaluation method was established by the analytic hierarchy process-entropy weight method (AHP-EWM) and the fuzzy mathematics method. Finally, evaluation results were verified by the split Hopkinson Pressure Bar (SHPB) experiment and permeability test. Results show that medium sandstone, argillaceous sandstone and siltstone exhibit excellent reformability, followed by coarse sandstone and fine sandstone, while the reformability of sandy mudstone is poor and is not able to accept BEP reservoir stimulation. The permeability improvement and the distribution of damage fractures before and after the SHPB experiment confirm the correctness of evaluation results. This research provides a reformability evaluation method for the BEP of the low-permeability sandstone-type uranium deposit, which contributes to the selection of the appropriate regional and stratigraphic horizon of the BEP and the enhanced ISL of the low-permeability sandstone-type uranium deposit.

Suggestion of Safety Level in Fish Farming by Impulsive Sound (충격소음으로 인한 양식어류 피해기준 제안)

  • Choi, Tae Hong;Kim, Jung Han;Song, Ha Lim;Ko, Chin Surk
    • Tunnel and Underground Space
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    • v.25 no.2
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    • pp.125-132
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    • 2015
  • As for noise and vibration occurring due to construction near fish farms, engineering and the technical opinions of experts in different areas were excluded in calculating any damage. The victims tend to present only biological consulting-based opinions while construction companies tend to present information on general construction noise and vibration as they have little biological knowledge on fish. So, the National Environmental Dispute Medication Commission presented specific damage standard in 2009 through studies on standard in calculating compensation and damage assessment of farm-raised fish that were affected by noise and vibration. Currently, 140 dB re $1{\mu}Pa$ is accepted as damage standard of underwater noise in the country. This standard is the RMS value of continuous sounds for more than a second, not the impulsive sounds. To look up the data on existing studies, fish showed different reactions to underwater sounds according to the different kinds of fish such as ostariophysan or non-ostariophysan, and pinnipeds or non-pinnipeds. So, this study will present damage standards for impulsive sounds in consideration of the differences in the characteristics of the impulsive and continuous sounds.