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In situ strength profiles along two adjacent vertical drillholes from digitalization of hydraulic rotary drilling

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Journal of Rock Mechanics and Geotechnical engineering 2023年第1期15卷 146-168页

作者： Xuefan Wang Peng Peng Zhigang Shan Zhongqi Yue Department of civil engineering The University of Hong KongHong KongChina PowerChina Huadong engineering corporation limited HangzhouChina

Drilling speed and associated analyses from factual field data of hydraulic rotary drilling have not been fully *** paper provides the reference and comparison for the utilization of drilling information from two adjacent vertical drillholes that were formed with the same hydraulic rotary drilling machine and *** analysis of original factual data is presented to obtain the constant drilling speed during net drilling *** to the factual data along two adjacent drillholes,the digitalization results respectively include 461 linear zones and 210 linear zones with their constant drilling speeds and associated drilling *** digitalization results can accurately present the spatial distributions and interface boundaries of drilled geomaterials and the results are consistent with the paralleled site *** weighted average drilling speeds from 2.335 m/min to 0.044 m/min represent 13 types of drilled geomaterials from soils to hard *** quantitative relation between drilling speed and strength property is *** digitalization results can statistically profile the basic strength quality grades of III to VI from soils to hard *** thickness distributions of four strength quality grades are presented for each individual type of geomaterials along two *** total,50.2%of geomaterials from drillhole A are grade IV and 57.4%of geomaterials from drillhole B are grade *** digitalization results can offer an accurate and cost-effective tool to quantitatively describe the spatial distribution and in situ strength profile of drilled geomaterials in the current drilling projects.

关键词： Drilling process monitoring(DPM) Hydraulic rotary coring process Constant drilling speed Coring-resistant strength

Investigation of cracking mechanism of the first tunnel lining during double-arch tunnel construction

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Underground Space 2024年第1期14卷 1-17页

作者： Yi Sui Xiaohui Cheng Zuozhou Zhao Weibin Ma Railway engineering Research Institute China Academy of Railway Sciences Corporation LimitedBeijing 100081China School of civil engineering Tsinghua UniversityBeijing 100084China

To solve the engineering problem of the first tunnel lining cracking caused by the second tunnel construction of double-arch highway tunnels,a research method combining distributed optical-fibre monitoring,inversion analysis and numerical simulation that can reflect lining cracking was *** fibres were laid on opposite sides of the steel arches inside the first tunnel *** optical-fibre monitoring was conducted continuously during the second tunnel *** on the fibre-optic strain profile,the lining cracking was deduced and warned in *** mechanical behaviour of the steel arch was investigated by the inversion analysis,which took into consideration the integrated impact of axial force and flexural moment.A two-dimensional(2D)load-structure method–based numerical model was established,considering the influence of different load distributions in each construction *** total strain rotating crack constitutive model was applied to reflect the cracking behaviour of concrete lining in the simulation,and the model was calibrated and verified in the *** analysis between the simulated strain distribution and the distributed optical-fibre monitoring results was carried *** deformation mode and crack distribution of the lining were *** cracking mechanism was ***,the second tunnel construction led to the loading at the top of the middle partition wall and the release of rock pressure in the first *** these load changes,the secondary lining of the first tunnel cracked on the inner side of the top of the middle partition wall owing to tension,and compression-bending failure occurred near the right arch ***,the influence of the parameters on the lining force was analysed,and a construction optimisation scheme was proposed.

关键词： Double-arch tunnel Cracking mechanism Distributed optical-fibre sensing Inversion analysis Total strain rotating crack model Loadstructure method

Experiences in using gas dispersion measurements to evaluate metallurgical performance of scavenger cleaner and recleaner circuit at Vale's Thompson Mill

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Journal of Central South University 2014年第10期21卷 3955-3962页

作者：刘洪均张炜孙春宝 School of civil and Environmental engineering University of Science and Technology Beijing Department of Business Administration Chinalco China Copper Corporation Limited

The performance of a flotation circuit is largely the result of the operator's response to visual clues. This includes manipulation of the gas input and how it is distributed to cells in a bank. A new gas dispersion technology was presented which was conducted to perform characterization tests in Outokumpu 30 m3 and 50 m3 flotation cells installed at Thompson Vale's concentrator, and subsequent data analysis. The experimental program was designed to establish "as-found" baseline conditions for each cell of the two-parallel banks in the scavenger-cleaner and recleaner circuit, to select and characterize one typical cell in the two banks with either different frother concentrations or different air flow rates, and establish what variables can be manipulated in future characterization work. A three-parameter model was developed in order to link the bubble size and frother concentration. This relationship can be used to correlate gas dispersion change to improved metallurgical performance.

关键词： bubble size bubble size distribution bubble surface area flux gas dispersion

Influence of bubble diameter and solids concentration on bubble stability: Development of a novel analytical approach

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Journal of Central South University 2014年第9期21卷 3588-3595页

The properties and thickness of the bubbles in the froth control the flotation process. There is no work showing how to measure bubble film composition and thickness by a straightforward manner. In this work, a novel approach, a custom-designed bubble cell associated with layer interferometry(in the UV-vis region) and FT-IR spectroscopy was used to investigate the effect of solid particle type(hydrophilic vs hydrophobic), concentration and bubble diameter on stability of a bubble blown in air. Stability was quantified by measuring bubble lifetime and hydrated film thickness. Kerosene with silicone oil as a foaming agent was used to evaluate the impact of bubble diameter(test series I). Frother solutions(MIBC, Dowfroth 250, Hexanol and F-150) were used for the solid type concentration experiments(test series II). In the first series of experiments, it was determined that as the diameter of a bubble increased from 10 to 25 mm, so did the hydrated film thickness from 350 to 1000 nm. In the second series, as the silica concentration increased(0 to 10%), an increase in bubble lifetime and hydrated film thickness was resulted(130%-250%). An impact of solid hydrophobicity was found but to a lesser degree than expected. It is possible that the small particle size(<0.1 m) of silica was responsible for this behavior. The findings are used to interpret the effect of solids in flotation froth.

关键词： bubble diameter bubble lifetime thin liquid film UV-visible

Investigation on the Folding Mode and Deployment Process of an Inflatable Boarding Platform for the Marine Emergency Evacuation System

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Computer Modeling in engineering & Sciences 2023年第4期135卷 483-510页

作者： Qiang Li Pan Chen Lihong Gao Dan Meng Jinjie Zou Huadong engineering(Shenzhen)corporation limited Shenzhen518100China Faculty of civil engineering and Geosciences Delft University of TechnologyDelft2628 CNThe Netherlands

Monopiles are the most common foundation form of offshore wind turbines,which bear the vertical load,lateral load and bending *** remains uncertain whether the applied vertical load increases the lateral deflection of the *** paper investigated the influence of vertical load on the behaviour of monopiles installed in the sand under combined load using three-dimensional numerical *** commercial software PLAXIS was used for simulations in this *** were modelled as a structure incorporating linear elastic material behaviour and soil was modelled using the Hardening-Soil(HS)constitutive *** monopiles under vertical load,lateral load and combined vertical and lateral loads were respectively studied taking into account the sequence of load application and pile slenderness ratio(L/D;L and D are the length and diameter of the pile).Results suggest that the sequence of load application plays a major role in how vertical load affects the deflection behaviour of the ***,when L/D ratios obtained by lengthening the pile while keeping its diameter constant are 3,5 and 8,the relationships between lateral load and the deflection behaviour of the pile under the effect of vertical load demonstrate a similar ***,the cause of increased lateral capacity of the pile under the action of applied vertical load in the common practical application case and in the VPL case was analyzed by studying the variation law of soil stress along the pile *** confirm that the confining effect of vertical load increases means effective stress of the soil around the pile,thus increasing soil stiffness and pile capacity.

关键词： Pile lateral capacity combined load sequence of load application L/D ratio

Influence of Vertical Load on Lateral-Loaded Monopiles by Numerical Simulation

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Computer Modeling in engineering & Sciences 2023年第4期135卷 465-481页

关键词： Pile lateral capacity combined load sequence of load application L/D ratio

单轴压缩下基于轴向塑性应变的岩石裂纹闭合应力与损伤应力阈值的评估方法

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Journal of Central South University 2023年第10期30卷 3335-3348页

作者：周子龙王培宇蔡鑫赵奕翰刘建民焉兆熙陈龙峰 School of Resources and Safety engineering Central South UniversityChangsha 410083China State Key Laboratory of Safety Technology of Metal Mines Changsha 410012China Power China Zhongnan engineering corporation limited Changsha 410014China ccfed civil engineering corporation limited Changsha 410004China

量化裂纹应力阈值对认识岩石材料的变形与破坏具有重要意义。本文首先提出了一种基于轴向塑性应变评估岩石裂纹闭合应力和损伤应力阈值的新模型。随后,通过比较提出方法与已有方法的估计结果,验证了本文提出方法的准确性。最后,讨论了... 详细信息

量化裂纹应力阈值对认识岩石材料的变形与破坏具有重要意义。本文首先提出了一种基于轴向塑性应变评估岩石裂纹闭合应力和损伤应力阈值的新模型。随后,通过比较提出方法与已有方法的估计结果,验证了本文提出方法的准确性。最后,讨论了弹性模量取值误差对应力阈值计算结果的影响。结果表明,提出方法计算结果与已有方法计算结果非常接近,说明提出方法可以准确识别岩石材料的裂纹闭合应力和损伤应力阈值。此外,本文提出方法能显著降低弹性参数取值对岩石应力阈值计算结果的影响,能够更客观地确定岩石材料的裂纹闭合应力和损伤应力阈值。基于以上结果,本文还提供了详细的计算流程图以消除弹性模量误差造成的影响。

关键词：裂纹闭合应力裂纹损伤应力轴向塑性应变岩石变形单轴压缩

Horizontal dynamic response of a large-diameter pipe pile considering the second-order effect of axial force

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Earthquake engineering and engineering Vibration 2018年第3期17卷 567-579页

作者： Luan Lubao Ding Xuanming Zhou Wei Zheng Changjie Qu Liming Key Laboratory of New Technology for Construction of Cities in Mountain Area College of Civil EngineeringChongqing UniversityChongqing 400045China Powerchina Chengdu engineering corporation limited Chengdu 611130China

The second-order effect of axial force on horizontal vibrating characteristics of a large-diameter pipe pile is theoretically *** equations of the pile-soil system are established based on *** wave equations of soil are decoupled through differential transformation and variable ***,expressions of soil displacements and horizontal resistances can be *** analytical solution of the pile is derived based on continuity conditions between the pile and soil,subsequently from which expressions of the complex impedances are *** are carried out to examine the second-order effect of axial force on the horizontal vibrating behavior of the pipe *** conclusions can be summarized as follows： stiffness and damping factors are decreased with the application of axial force on the pile head; distributions of the pile horizontal displacement and rotation angle are regenerated due to the second-order effect of the applied axial force; and redistributions of the bending moment and shearing force occur due to the second-order effect of the applied axial force.

关键词： axial force second-order effect horizontal vibration pipe pile analytical solution

Mineralogical characterization of copper sulfide tailings using automated mineral liberation analysis: A case study of the Chambishi Copper Mine tailings

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International Journal of Minerals,Metallurgy and Materials 2021年第6期28卷 944-955页

作者： Xiao-liang Zhang Jue Kou Chun-bao Sun Rui-yang Zhang Min Su Shuo-fu Li School of civil and Resource engineering University of Science and Technology BeijingBeijing 100083China Non-ferrous corporation Africa Mining Public limited Company Kitwe 22592Zambia

As ore grades constantly decline,more copper tailings,which still contain a considerable amount of unrecovered copper,are expected to be produced as a byproduct of froth *** research reveals the occurrence mechanism of copper minerals in typical copper sulfide tailings using quantitative mineral liberation analysis(MLA)integrated with scanning electron microscopy–energy dispersive spectroscopy(SEM–EDS).A comprehensive mineralogical characterization was carried out,and the results showed that almost all copper minerals were highly disseminated within coarse gangue particles,except for 9.2wt%chalcopyrite that occurred in the 160–180μm size *** predominant copper-bearing mineral was chalcopyrite,which was closely intergrown with orthoclase and muscovite rather than *** flotation tailings sample still contained 3.28wt%liberated chalcopyrite and 3.13wt%liberated bornite because of their extremely fine *** SEM–EDS analysis further demonstrated that copper minerals mainly occurred as fine dispersed and fully enclosed structures in gangue *** information obtained from this research could offer useful references for recovering residual copper from flotation tailings.

关键词： copper tailings chalcopyrite mineral liberation analysis particle size boundary breakage