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A novel elastoplastic model for Yunnan sandstone under poly-axial loading

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International Journal of Mining Science and Technology 2023年第7期33卷 801-814页

作者： Xu Li Guangyao Si joung oh Ismet Canbulat Rui Kong Jian Zhang School of Minerals and Energy Resources Engineering University of New South WalesSydney NSW 2052Australia Key Laboratory of Ministry of Education on Safe Mining of Deep Metal Mines Northeastern UniversityShenyang 110819China School of Safety Science and Engineering Henan Polytechnic UniversityJiaozuo 454003China

The lack of understanding of plastic hardening(softening)laws,especially under anisotropic stress conditions,results in inappropriate geotechnical management.Most of the yielding envelopes do not consider the effect of intermediate principal stress and the influence of Lode's angle.In addition,the application of plastic flow rules regarding yielding surfaces compromises the softening of rock internal friction as well as the influence of Lode's angle on the plastic potential.Moreover,the ductility to brittleness transition in the intermediate principal stress direction still requires a theoretical foundation.In this study,based on poly-axial testing results of Yunnan sandstone,we adopted a failure criterion with the intermediate principal stress proposed by Menétrey and Willam.The proposed new failure envelope was applied to capture the plastic evolution of rock samples.A plastic hardening-softening model is constructed,based on the framework of the plastic theory.The softening envelope is modified to better present the stress drop and considers the deterioration of rock internal friction in the post-peak stage of poly-axial loading.The differential of plastic potential according to the principal stresses is also modified,considering the rotation of Lode's angle in the poly-axial loading tests.The model results were compared with laboratory testing results,which showed great consistency across 9 different loading tests(5 under triaxial stress and 4 under poly-axial stress with 22 stress-strain curves in total).The induced brittleness by the intermediate principal stress is also well captured by the proposed model.

关键词： Elastoplastic model Rock mechanics Poly-axial stress state True-triaxial

An investigation of machine learning techniques to estimate minimum horizontal stress magnitude from borehole breakout

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International Journal of Mining Science and Technology 2022年第5期32卷 1021-1029页

作者： Huasheng Lin Sarvesh Kumar Singh Zizhuo Xiang Won Hee Kang Simit Raval joung oh Ismet Canbulat Glencore Coal Assets Australia Mount Thorley 2330Australia School of Minerals and Energy Resources Engineering University of New South WalesSydney 2052Australia Centre for Infrastructure Engineering School of EngineeringWestern Sydney UniversityPenrith 2751Australia

Borehole breakout is a widely utilised phenomenon in horizontal stress orientation determination,and breakout geometrical parameters,such as width and depth,have been used to estimate both horizontal stress magnitudes.However,the accuracy of minimum horizontal stress estimation from borehole breakout remains relatively low in comparison to maximum horizontal stress estimation.This paper aims to compare and improve the minimum horizontal stress estimation via a number of machine learning(ML)regression techniques,including parametric and non-parametric models,which have rarely been explored.ML models were trained based on 79 laboratory data from published literature and validated against 23 field data.A systematic bias was observed in the prediction for the validation dataset whenever the horizontal stress value exceeded the maximum value in the training data.Nevertheless,the pattern was captured,and the removal of systematic bias showed that the artificial neural network is capable of predicting the minimum horizontal stress with an average error rate of 10.16%and a root mean square error of 3.87 MPa when compared to actual values obtained through conventional in-situ measurement techniques.This is a meaningful improvement considering the importance of in-situ stress knowledge for underground operations and the availability of borehole breakout data.

关键词： Borehole breakout In-situ stress estimation Comparative analysis Machine learning

Quantitative assessment of the spatio-temporal correlations of seismic events induced by longwall coal mining

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Journal of Rock Mechanics and Geotechnical Engineering 2022年第5期14卷 1406-1420页

作者： Shuyu Wang Guangyao Si Changbin Wang Wu Cai Binglei Li joung oh Ismet Canbulat School of Minerals and Energy Resources Engineering University of New South WalesSydney2052Australia State Key Laboratory of Coal Resources and Safe Mining School of MinesChina University of Mining and TechnologyXuzhou221116China Zijin School of Geology and Mining Fuzhou UniversityFuzhou350108China

Rock failure process as a natural response to mining activities is associated with seismic events, which can pose a potential hazard to mine operators, equipment and infrastructures. Mining-induced seismicity has been found to be internally correlated in both time and space domains as a result of rock fracturing during progressive mining activities. Understanding the spatio-temporal(ST) correlation of mininginduced seismic events is an essential step to use seismic data for further analysis, such as rockburst prediction and caving assessment. However, there are no established methods to perform this critical task. Input parameters used for the prediction of seismic hazards, such as the time window of past data and effective prediction distance, are determined based on site-specific experience without statistical or physical reasons to support. Therefore, the accuracy of current seismic prediction methods is largely constrained, which can only be addressed by quantitively assessing the ST correlations of mininginduced seismicity. In this research, the ST correlation of seismic event energy collected from a study mine is quantitatively analysed using various statistical methods, including autocorrelation function(ACF), semivariogram and Moran’s I analysis. In addition, based on the integrated ST correlation assessment, seismic events are further classified into seven clusters, so as to assess the correlations within individual clusters. The correlation of seismic events is found to be quantitatively assessable, and their correlations may vary throughout the mineral extraction process.

关键词： Spatial correlation Temporal correlation Autocorrelation function(ACF) Semivariogram Scale of fluctuation

New risk assessment methodology for coal mine excavated slopes

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International Journal of Mining Science and Technology 2018年第4期28卷 581-590页

作者： Alison McQuillan Ismet Canbulat Dan Payne joung oh School of Minerals and Energy Resources Engineering UNSW SydneySydney 2052Australia BHP Billiton Coal Level 11480 Queen StBrisbaneQueensland 4000Australia

This paper presents a new risk assessment methodology for coal mine excavated slopes. This new empirical-statistical slope stability assessment methodology(SSAM) is intended for use by geotechnical engineers at both the design review and operational stages of a mine's life to categorise the risk of an excavated coal mine slope. A likelihood of failure is determined using a new slope stability classification system for excavated coal mine slopes developed using a database of 119 intact and failed case studies sourced from open cut coal mines in Australia. Consequence of failure is based on slope height and stand-off distance at the toe of the excavated slope. Results are presented in a new risk matrix, with slope risk being divided into low, medium and high categories. The SSAM is put forward as a new risk assessment methodology to assess the potential for, and consequence of, excavated coal mine slope failure.Unlike existing classification systems, assumptions about the likely failure mode or mechanism are not required. Instead, the SSAM applies an approach which compares the conditions present within the excavated slope face, with the known past performance of slopes with similar geotechnical and geometrical conditions, to estimate the slope's propensity for failure. The SSAM is novel in that it considers the depositional history of strata in an excavated slope and how this sequence affects slope stability. It is further novel in that it does not require explicit measurements of intact rock, rock mass and/or defect strength to rapidly calculate a slope's likelihood of failure and overall risk. Ratings can be determined entirely from visual observations of the excavated slope face. The new SSAM is designed to be used in conjunction with existing slope stability assessment tools.

关键词：风险评价方法论挖掘煤矿斜坡稳定性分类系统数据库开发澳大利亚

Methods applied in Australian industry to evaluate coal mine slope stability

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International Journal of Mining Science and Technology 2020年第2期30卷 151-155页

作者： Alison McQuillan Ismet Canbulat joung oh School of Minerals and Energy Resources Engineering UNSW SydneyAustralia

Strata failure is a principal hazard in open cut coal mining as it has the potential to cause multiple fatalities.Prior to the excavation of any slope,a geotechnical assessment should review the likely slope performance,including the risk of slope failure.Controls to manage this risk to an acceptable level should accompany the geotechnical analysis.A survey of 43 practising geotechnical engineers indicated that kinematic and 2D limit equilibrium analyses were the methods most commonly applied to analyse excavated slope stability.While these methods are well established and widely applied in the broad rock engineering disciplines(e.***.civil,hard rock),a recent review of over 60 slope failures suggests these methods have limited suitability for modelling the complex failure mechanisms observed in excavated coal mine slopes.Kinematic techniques do not adequately capture the rock mass component of excavated slope failure and do not provide a geospatial location of potential failure,while 2D limit equilibrium techniques do not adequately capture the 3D mechanisms of excavated slope failures.Methods which do consider the 3D mechanisms of slope failure are summarized for industry consideration and application.

关键词： Slope stability 2D 3D Open cut coal mine Limit equilibrium

A review of cavability evaluation in longwall top coal caving

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International Journal of Mining Science and Technology 2017年第6期27卷 907-915页

作者： Tien Dung Le Rudrajit Mitra joung oh Bruce Hebblewhite School of Mining Engineering The University of New South Wales Sydney NSW 2052 Australia

Longwall Top Coal Caving has been considered as one of the most effective technologies for the extraction of underground thick coal seams. A large number of studies on the applicability of Longwall Top Coal Caving into new mine sites have linked the success of its application to the geo mechanical understanding of the cavability of the top coal. The paper aims to improve the knowledge of the top coal cavability evaluation. A range of parameters that affect the top coal cavability were first identified. Afterward, a number of cavability assessment methods and classifications were reviewed. The result is important in that it assists researchers in developing an advanced and reliable tool for the top coal cavability evaluation.

关键词： Longwall top coal caving Cavability Numerical modelling Caving mechanism Caving classification

A hybrid swarm population of Pinus densiflora × P. sylvestris inferred from sequence analysis of chloroplast DNA and morphological characters

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Journal of Forestry Research 2013年第1期24卷 53-60页

作者： Young Hee joung Jerry L. Hill Jung oh Hyun Ding Mu Juchun Luo Do Hyung Lee Takayuki Kawahara Jeung Keun Suh Mark S. Roh Chonnam National University School of Biological Sciences & TechnologyGwangjuKorea US Department of Agriculture Forest ServiceDorena Genetic Resource CenterWashington State UniversityPullmanWA99164USA Seoul National University College of Agriculture and Life SciencesSeoulKorea Chinese Academy of Agricultural Science Beijing Forestry University College of Resources and Environment Yeungnam University College of Natural ResourcesDepartment of Forest ResourcesGyeongsanKorea Hokkaido Research Center Forestry and Forest Products Research InstituteSapporoJapan. Dankook University School of Bio-Resource ScienceDepartment of Environment HorticultureCheonanKorea. US Department of Agriculture Agricultural Research ServiceUS National ArboretumFloral and Nursery Plants Research UnitBeltsvilleMD 20705USA.

To confirm a hybrid swarm population of Pinus densiflora × P. sylvestris in Jilin, China, we used needles and seeds from P. densiflora, P. sylvestris, and P. densiflora × P. sylvestris collected from natural stands or experimental stations to study whether shoot apex morphology of 4-year old seedlings can be correlated with the sequence of a chloroplast DNA simple sequence repeat marker （cpDNA SSRs）. Total genomic DNA was extracted and subjected to sequence analysis of the pine cpDNA SSR marker Pt15169. Results show that morphological characters from 4-year old seedlings did not correlate with sequence variants of this marker. Marker haplotypes from all P. sylvestris trees had a CTAT element that was absent from all sampled P. densiflora trees. However, both haplotype classes involving this insertion/deletion element were found in a P. densiflora × P. sylvestris population and its seedling progeny. It was concluded that the P. densiflora × P. sylvestris accessions sampled from Jilin, China resulted from bi-directional crosses, as evidenced by both species’ cpDNA haplotypes within the hybrid swarm population.

关键词： P. sylvestris var. sylvestriformis chloroplast DNA simplesequence repeat sequencing hybrid swarm population

Gastric leptomeningeal carcinomatosis: Multi-center retrospective analysis of 54 cases

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World Journal of Gastroenterology 2009年第40期15卷 5086-5090页

作者： Sung Yong oh Su-Jin Lee Jeeyun Lee Suee Lee Sung-Hyun Kim Hyuk-Chan Kwon Gyeong-Won Lee Jung Hun Kang In Gyu Hwang joung-Soon Jang Ho Yeong Lim Young Suk Park Won Ki Kang Hyo-Jin Kim Department of Internal Medicine and Medical Research Center for Cancer Molecular Therapy Dong-A University College of Medicine Division of Hematology/Oncology Department of MedicineSamsung Medical Center Department of InternalMedicine Gyeongsang National University School of Medicine Department of Internal Medicine College of MedicineChung-Ang University

AIM: To identify the clinical features and outcomes of infrequently reported leptomeningeal carcinomatosis (LMC) of gastric cancer.METHODS: We analyzed 54 cases of cytologically confirmed gastric LMC at four institutions from 1994 to 2007.RESULTS: The male-to-female ratio was 32:22, and the patients ranged in age from 28 to 78 years (median,48.5 years). The majority of patients had advanced disease at initial diagnosis of gastric cancer. The clini-cal or pathologic tumor, node and metastasis stage ofthe primary gastric cancer wasin 38 patients (70%).The median interval from diagnosis of the primarymalignancy to the diagnosis of LMC was 6.3 mo, rang-ing between 0 and 73.1 mo. Of the initial endoscopic f indings for the 45 available patients, 23 (51%) of the patients were Bormann typeand 15 (33%) patientswere Bormann type. Pathologically, 94% of cases proved to be poorly differentiated adenocarcinomas. Signet ring cell component was also observed in 40% of patients. Headache (85%) and nausea/vomiting (58%) were the most common presenting symptoms of LMC. A gadolinium-enhanced magnetic resonance imaging was conducted in 51 patients. Leptomeningeal enhancement was noted in 45 cases (82%). Intrathecal (IT) chemotherapy was administered to 36 patients-primarily methotrexate alone (61%), but also in combi-nation with hydrocortisone/± Ara-C (39%). The median number of IT treatments was 7 (range, 1-18). Concomitant radiotherapy was administered to 18 patients, and concomitant chemotherapy to seven patients. Sev-enteen patients (46%) achieved cytological negative conversion. Median overall survival duration from the diagnosis of LMC was 6.7 wk (95% CI: 4.3-9.1 wk). In the univariate analysis of survival duration, hemoglobin, IT chemotherapy, and cytological negative conversion showed superior survival duration (P = 0.038, P = 0.010, and P = 0.002, respectively). However, in our multivariate analysis, only cytological negative conversion was predictive of relatively longer survival duration (3.6, 6.7 and 14.6 wk, P = 0.030,

关键词：胃疾病治疗临床 METHODS

Attenuated FOLFIRINOX in the salvage treatment of gemcitabine-refractory advanced pancreatic cancer: a phase II study

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Cancer Communications 2018年第1期38卷 344-351页

作者： Jung Hoon Kim Sang-Cheol Lee Sung Yong oh Seo-Young Song Namsu Lee Eun Mi Nam Soonil Lee In Gyu Hwang Hyo Rak Lee Kyu Taek Lee Sang-Byung Bae Han Jo Kim joung Soon Jang Do Hyoung Lim Hyun Woo Lee Seok Yun Kang Jung Hun Kang Department of Internal Medicine Institute of Health SciencesGyeongsang National University15 Jinju-daero 816beon-gilJinju 52727Republic of Korea Divsion of Hematology and Oncology Department of Internal MedicineSoonchunhyang University Hospital CheonanCheonan 31151Republic of Korea Department of Internal Medicine Dong-A University HospitalBusan 49201Republic of Korea Department of Internal Medicine Kangwon National University School of MedicineChuncheon 24289Republic of Korea Divsion of Hematology and Oncology Department of Internal MedicineSoonchunhyang University Hospital SeoulSeoul 04401Republic of Korea Department of Internal Medicine Ewha Womans UniversityCollege of MedicineSeoul 07985Republic of Korea Department of Internal Medicine Dankook University HospitalCheonan 31116Republic of Korea Department of Internal Medicine Chung-Ang UniversityCollege of MedicineSeoul 06973Republic of Korea Division of Hematology and Medical Oncology Department of Internal MedicineKorea Cancer HospitalSeoul 01812Republic of Korea Department of Hematology-Oncology Ajou University HospitalSuwon 16499Republic of Korea

Background:Combination therapy with oxaliplatin,irinotecan,fluorouracil,and leucovorin(FOLFIRINOX)chemotherapy drastically improves survival of advanced pancreatic cancer patients.However,the efficacy of FOLFIRINOX as a second-line treatment after gemcitabine failure has not been tested prospectively.We investigated the feasibility and safety of attenuated FOLFIRINOX in patients with gemcitabine-refractory advanced pancreatic cancer.Methods:A multicenter phase II prospective open-label,single-arm study was conducted at 14 hospitals.Patients with histologically proven invasive ductal pancreatic adenocarcinoma,a measurable or evaluable lesion,Eastern Cooperative Oncology Group performance status 0 or 1,adequate organ function,and aged 19 years or older were eligible.Attenuated FOLFIRINOX consisted of oxaliplatin 65 mg/m2,irinotecan 135 mg/m2,and leucovorin 400 mg/m2 injected intravenously on day 1 and 5-fluorouracil 2000 mg/m2 continuously infused intravenously over 46 h on days 1-2,repeated every 2 weeks.The primary endpoint was progression-free survival from the initiation of FOLFIRINOX.Secondary endpoints were the objective response rate,disease control rate,overall survival,safety,and tolerability.We estimated overall survival and progression-free survival using the Kaplan-Meier methods.Results:We enrolled 39 patients from 14 institutions.The objective response rate was 10.3%,while the disease control rate was 64.1%.The 6-month and 1-year overall survival rates were 59.0%and 15.4%,respectively.Median progression-free survival and overall survival were 3.8 months(95%confidence interval[CI]1.5-6.0 months)and 8.5 months(95%CI 5.6-11.4 months),respectively.Grade 3 or 4 adverse events were neutropenia(41.0%),nausea(10.3%),anorexia(10.3%),anemia(7.7%),mucositis(7.7%),pneumonia/pleural effusion(5.1%),and fatigue(5.1%).One treatment-related death attributable to septic shock occurred.Conclusion:Attenuated FOLFIRINOX may be promising as a second-line therapy for gemcitabine-refractory pancre-atic cancer.

关键词： Attenuated FOLFIRINOX Second-line Pancreatic cancer Gemcitabine