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Underground ground control monitoring and interpretation,and numerical modeling, and shield capacity design

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International Journal of Mining Science and Technology 2019年第1期29卷 79-85页

作者： Syd S.Peng Jingyi Cheng Feng Du Yuting Xue Department of Mining Engineering West Virginia University Key Laboratory of Deep Coal Resource Mining(CUMT) Ministry of Education of ChinaSchool of MinesChina University of Mining&TechnologyXuzhou School of Energy Science and Engineering Henan Polytechnic University

Mine or longwall panel layout is a 3D structure with highly non-uniform stress distribution. Recognition of such fact will facilitate underground problem identification/investigation and solving by numerical modeling through proper model construction. Due to its versatility, numerical modeling is the most popular method for ground control design and problem solving. However numerical modeling results require highly experienced professionals to interpret its validity/applicability to actual mining operations due to complicated mining and geological conditions. Underground ground control monitoring is routinely performed to predict roof behavior such as weighting and weighting interval without matching observation of face mining condition while the mining pressures are being monitored, resulting in unrealistic interpretation of the obtained data on mining pressure. The importance of ground control pressure monitoring and simultaneous observation of mining and geological conditions is illustrated by an example of shield leg pressure monitoring and interpretation in an U.S. longwall coal mine: it was found that the roof strata act like a plate, not an individual block of the size of a shield dimension, as commonly assumed by all researchers and shield capacity is not a fixed property for a longwall panel or a mine or a coal seam. A new mechanism on the interaction between shield's hydraulic leg pressure and roof strata for shield loading is proposed.

关键词： Mine structure Ground control monitoring Numerical modeling shield leg pressure Periodic weighting

The influence of hand hole on the ultimate strength and crack pattern of shield tunnel segment joints by scaled model test

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Frontiers of Structural and Civil Engineering 2019年第5期13卷 1200-1213页

作者： Shaochun WANG Xi JIANG Yun BAI Department of Geotechnical Engineering College of Civil EngineeringTongji UniversityShanghai 200092China

With the shield tunnel going deeper and deeper, the circumferential axial force becomes the governing factor rather than the bending moment. The hand hole acts as a weak point and initial damage in the segment joint especially when the circumferential axial force is extremely high. Despite the wide application of steel fiber or synthetic fiber in t|ie tunneling, limited researches focus on the structural responses of segment joint with macro structural synthetic fiber (MSSF). In this paper, a 1:2 reduced-scale experiment was conducted to study the structural perfonnance of the segment joint with different types of hand holes under ultra-high axial force. Special attention is paid to failure mode and structural performance (bearing capacity, deformation, cracking, and toughness). Moreover, segment joints with MSSF are also tested to evaluate the effects of MSSF on the failure mode and structural performance of the segment joints. The experiment results show that the hand hole becomes the weakest point of the segment joint under ultra-high axial force. A\/-type crack pattern is always observed before the final failure of the segment joints. Different types and sizes of the hand hole have different degree of influences on the structural behavior of segment joints. The segment joint with MSSF shows higher ultimate bearing capacity and toughness compared to segment joint with common concrete. Besides, the MSSF improves the initial cracking load and anti-spallling resistance of the segment joint.

关键词： shield tunneling structural synthetic fiber concrete hand hole segment joint ultimate bearing capacity crack pattern

Prediction of shield tunneling-induced ground settlement using machine learning techniques

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Frontiers of Structural and Civil Engineering 2019年第6期13卷 1363-1378页

作者： Renpeng CHEN Pin ZHANG Huaina WU Zhiteng WANG Zhiquan ZHONG Key Laboratory of Building Safety and Energy Efficiency Hunan UniversityChangsha 410082China National Joint Research Center for Building Safety and Environment Hunan UniversityChangsha 410082China College of Civil Engineering Hunan UniversityChangsha 410082China China Construction Fifth Engineering Division Co. LtdChangsha 410082China

Predicting the tunneling-induced maximum ground surface settlement is a complex problem since the settlement depends on plenty of intrinsic and extrinsic factors.This study investigates the efficiency and feasibility of six machine learning(ML)algorithms,namely,back-propagation neural network,wavelet neural network,general regression neural network(GRNN),extreme learning machine,support vector machine and random forest(RF),to predict tunneling?induced settlement.Field data sets including geological conditions,shield operational parameters,and tunnel geometry collected from four sections of tunnel with a total of 3.93 km are used to build models.Three indicators,mean absolute error,root mean absolute error,and coefficient of determination the(7?2)are used to demonstrate the performance of each computational model.The results indicated that ML algorithms have great potential to predict tunneling-induced settlement,compared with the traditional multivariate linear regression method.GRNN and RF algorithms show the best performance among six ML algorithms,which accurately recognize the evolution of tunneling-induced settlement.The correlation between the input variables and settlement is also investigated by Pearson correlation coefficient.

关键词： EPB shield shield tunneling settlement prediction machine learning

Optimized Fuzzy Clustering Method for Health Monitoring of shield Tunnels

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Transactions of Nanjing University of Aeronautics and Astronautics 2015年第3期32卷 325-333页

作者：周发张巍孙可唐心煜王小敏 School of Earth Sciences and Engineering Nanjing University

Since health monitoring of shield tunnels generally employs multiple sensors belonging to different types,a fine analysis on massive monitoring data,as well as further quantitative health grading,is really challenging.An optimized fuzzy clustering analysis method based on the fuzzy equivalence relation is proposed for health monitoring of shield tunnels.Clustering results are auto-generated by using fuzzy similarity-valued map.The results follow the idea of unsupervised classification.Moreover,a convenient new health index HI is proposed for a fast tunnel-health grading.A case study on Nanjing Yangtze River Tunnel is presented to validate this method.Three types of indicators,namely soil pressure,pore water pressure and steel strain,are used to develop the clustering model.The clustering results are verified by analyzing the engineering geological conditions;the validity and the efficacy of the proposed method are also demonstrated.Further,the fuzzy clustering analysis also represents a potential for identifying abnormal monitoring data.This investigation indicates the fuzzy clustering analysis method is capable of characterizing the fuzziness of tunnel health,and beneficial to clarify the tunnel health evaluation uncertainties.

关键词： shield tunnel health monitoring optimized fuzzy cl

Late Neoproterozoic adakitic magmatism of the eastern Arabian Nubian shield

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Geoscience Frontiers 2019年第6期10卷 1981-1992页

作者： Grant M.Cox John Foden Alan S.Collins Centre for Tectonics Resources and Exploration(TRaX) Dept of Earth SciencesThe University of Adelaide

Late Neoproterozoic adakitic magmatism within the Eastern Arabian Nubian shield has been dated at633.2±9.0 Ma(2σ).These magnas intrude the forearc Ad Dawadimi Basin,which is composed of metapelitic schists and greywacke along with ophiolitic melanges of boninitic affinity which underwent inversion and deformation by^620 Ma.This adakitic magmatism,while intruding parts of the Ad Dawadimi Basin,predates this deformation,but is possibly coincident with basin closure.As adakitic magmatism requires melting of an amphibolite or eclogitic source,empirical and experimental constraints require anomalously hot supra-subduction zone mantle.Considering that this magmatism immediately predates basin inversion,these magmas possibly pinpoint the timing of the slab breaking,marking the terminal stages of arc magmatism,terrane accretion and the influx of hot oceanic asthenospheric mantle.This influx of hot asthenospheric mantle may also be responsible for postcolltsional A-type magmatism.

关键词： Arabian Nubian shield Adakites A-type magmatism

Zircon U-Pb and Lu-Hf isotope constraints on Archean crustal evolution in Southeastern Guyana shield

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Geoscience Frontiers 2019年第4期10卷 1477-1506页

作者： Joao Marinho Milhomem Neto Jean-Michel Lafon Programa de Pos-graduacao em Geologia e Geoquimica-PPGG Instituto de Geociencias-IGUniversidade Federal do Para-UFPA66075-110BelemParaBrazil Laboratório de Geologia Isotópica-Pará-Iso IG-UFPA66075-110BelémParáBrazil

The southeastern Guyana shield,northeast Amazonian Craton,in the north of Brazil,is part of a widespread orogenic belt developed during the Transamazonian orogenic cycle(2.26-1.95 Ga)that includes a large Archean continental landmass strongly reworked during the Transamazonian orogeny,named Amapa Block.It consists mainly of a high-grade metamorphic granulitic-migmatitic-gneiss complex,of Meso-to Neoarchean age and Rhyacian granitoids and supracrustal sequences.For the first time,coupled U-Pb and Lu-Hf isotope data were obtained on zircon by LA-ICP-MS from five tectono-stratigraphic units of the Archean basement and one Paleoproterozoic intrusive rock,in order to investigate the main episodes of crustal growth and reworking.Whole-rock Sm-Nd isotope data were compared to the zircon Lu-Hf data.Three main magmatic episodes were defined by U-Pb zircon dating,two in the Mesoarchean(~3.19 Ga and 2.85 Ga)and one in the Neoarchean(~2.69-2.65 Ga).SubchondriticεHf(t)values obtained for almost all investigated units indicate that crustal reworking processes were predominant during the formation of rocks that today make up the Amapa Block.Hf-TDMC model ages,ranging from2.99 Ga to 3.97 Ga,indicate that at least two important periods of mantle extraction and continental crust formation occurred during the Archean in southeastern Guyana shield,an older one in the Eoarchean(~4.0 Ga)and a younger one in the Mesoarchean(~3.0-3.1 Ga).The latter is recognized as an important period of crustal accretion worldwide.The recognition of an Eoarchean episode to the southeastern most part of the Guyana shield is unprecedented and was not recorded by whole-rock Sm-Nd data,which were restricted to the Meso-Paleoarchean(2.83 Ga to 3.51 Ga).This finding reveals t hat continental crust generation in the Amazonian Craton began at least 500 Ma earlier than previously suggested by the SmNd systematics.

关键词： U-Pb-Lu-Hf isotopes Zircon Archean crustal evolution Southeastern Guyana shield Amazonian Craton

Improved Particle Swarm Optimization for Selection of shield Tunneling Parameter Values

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Computer Modeling in Engineering & Sciences 2019年第2期118卷 317-337页

作者： Gongyu Hou Zhedong Xu Xin Liu Cong Jin Department of Mechanics and Civil Engineering China University of Mining&TechnologyBeijing100083China.

This article proposes an exponential adjustment inertia weight immune particle swarm optimization(EAIW-IPSO)to enhance the accuracy and reliability regarding the selection of shield tunneling parameter values.According to the iteration changes and the range of inertia weight in particle swarm optimization algorithm(PSO),the inertia weight is adjusted by the form of exponential function.Meanwhile,the self-regulation mechanism of the immune system is combined with the PSO.12 benchmark functions and the realistic cases of shield tunneling parameter value selection are utilized to demonstrate the feasibility and accuracy of the proposed EAIW-IPSO algorithm.Comparison with other improved PSO indicates that EAIW-IPSO has better performance to solve unimodal and multimodal optimization problems.When solving the selection of shield tunneling parameter values,EAIW-IPSO can provide more accurate and reliable references for the realistic engineering.

关键词： Inertia weight EAIW-IPSO self-regulation mechanism shield tunneling parameter.

Earth pressure balance control for EPB shield

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Science China(Technological Sciences) 2009年第10期52卷 2840-2848页

作者： YANG HuaYong SHI Hu GONG GuoFang HU GuoLiang State Key Laboratory of Fluid Power Transmission and Control Zhejiang UniversityHangzhou 310027China College of Mechatronics East China Jiaotong UniversityNanchang 330013China

This paper mainly deals with the critical technology of earth pressure balance (EPB) control in shield tunneling. On the assumption that the conditioned soil in the working chamber of the shield is plasticized, a theoretical principle for EPB control is proposed. Dynamic equilibrium of intake volume and discharge volume generated by thrust and discharge is modeled theoretically to simulate the earth pressure variation during excavating. The thrust system and the screw conveyor system for earth pressure control are developed based on the electro-hydraulic technique. The control models of the thrust speed regulation of the cylinders and the rotating speed adjustment of the screw conveyor are also presented. Simulation for earth pressure control is conducted with software AMESim and MATLAB/Simulink to verify the models. Experiments are carried out with intake control in clay soil and discharge control in sandy gravel section, respectively. The experimental results show that the earth pressure variations in the working chamber can be kept at the expected value with a practically acceptable precision by means of real-time tuning the thrust speed or the revolving speed of discharge system.

关键词： earth pressure balance (EPB) shield thrust system screw conveyor hydraulic system

Upper mantle anisotropy inferred from shear wave splitting beneath the Eastern Indian shield region

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Geoscience Frontiers 2018年第6期9卷 1911-1920页

作者： Kuntal Bhukta Prosanta K.Khan Prantik Mandal Indian Institute of Technology(Indian School of Mines) DhanbadIndia National Geophysical Research Institute HyderabadIndia

We estimate the shear wave splitting parameters vis-a-vis the thicknesses of the continental lithosphere beneath the two permanent seismic broadband stations located at Dhanbad(DHN) and Bokaro(BOKR) in the Eastern Indian shield region. Broadband seismic data of 146 and 131 teleseismic earthquake events recorded at DHN and BOKR stations during 2007-2014 were analyzed for the present measurements.The study is carried out using rotation-correlation and transverse component minimization methods. We retain our "Good", "Fair" and "Null" measurements, and estimate the splitting parameters using 13 "Good" results for DHN and 10 "Good" results for BOKR stations. The average splitting parameters(φ,δt)for DHN and BOKR stations are found to be 50.76°±5.46° and 0.82±0.2 s and 56.30°±5.07° and0.95 ± 0.17 s, and the estimated average thicknesses of the anisotropic layers beneath these two stations are ～94 and ～109 km,respectively. The measured deviation of azimuth of the fast axis direction(0)from the absolute motion of the Indian plate ranges from ～8° to 14°. The measured deviation of azimuth of the fast axis direction(0) from the absolute motion of the Indian plate ranges from ～8° to 14°. The eastward deviation of the fast axis azimuths from absolute plate motion direction is interpreted to be caused by induced outflow from the asthenosphere. Further, the delay time found in the present analysis is close to the global average for continental shield areas, and also coherent with other studies for Indian shield regions. The five "Null" results and the lower delay time of ～0.5-0.6 s might be indicating multilayer anisotropy existing in the mantle lithosphere beneath the study area.

关键词： Eastern Indian shield Seismic anisotropy Splitting parameters Absolute plate motion