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Experimental and numerical evaluation on debonding of fully grouted rockbolt under pull‑out loading

International Journal of Coal Science & Technology 2022年第1期9卷 84-98页

作者： Shuisheng Yu wancheng zhu Leilei Niu Center for Rock Instability and Seismicity Research Department of Mining EngineeringSchool of Resource and Civil EngineeringNortheastern UniversityShenyang 110819China School of Architectural Engineering Zhongyuan University of TechnologyZhengzhou 450007China

The axial loading in rockbolts changes due to stress redistribution and rheology in the country rock *** a change may lead to debonding at rockbolt to grout interface or rupture of the *** this study,based on laboratory experiments,ultrasonic guided wave propagation in fully grouted rockbolt under different pull-out loads was investigated in order to examine the resultant debonding of *** signals obtained from the ultrasonic monitoring during the pull-out test were processed using wavelet multi-scale analysis and frequency spectrum analysis,the signal amplitude and the amplitude ratio(Q)of low frequency to high frequency were defined to quantify the debonding of *** addition to the laboratory test,numerical simulation on the effect of the embedment lengths on ultrasonic guided wave propagation in rockbolt was conducted by using a damage-based model,and the debonding between rockbolt and cement mortar was numerically *** was confirmed that the ultrasonic guided wave propagation in rockbolt was very sensitive to the debonding because of pull-out load,therefore,the critical bond length could be calculated based on the propagation of guided wave in the grouted *** time domain,the signal amplitude in rockbolt increased with pull-out load from 0 to 100 kN until the completely debonding,thus quantifying the debonding under the different pull-out *** the frequency domain,as the Q value increased,the debonding length of rockbolt decreased *** numerical results confirmed that the guided wave propagation in the fully grouted rockbolt was effective in detecting and quantifying the debonding of rockbolt under pull-out load.

关键词： Fully grouted rockbolt Debonding Pull-out load Ultrasonic guided wave propagation

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Theoretical predictions of viscosity of methane under confined conditions

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Chinese Journal of Chemical Engineering 2016年第7期24卷 904-908页

作者： Yingying Liu Di Zhou wancheng zhu Department of Chemical Engineering Qufu Normal University

Density functional theory has been confirmed as a reliable approach in the descriptions of inhomogeneous *** integrating the density functional theory into the revised local average density model, a theoretical approach is constructed to investigate the local shear viscosity in the confined conditions. In the density functional theory,the weighted density approximation for attractive part and the modified fundamental measure theory for repulsion contribution are adopted to accurately describe the inhomogeneous systems. By comparing with simulation data, the theoretical model is tested. In this work, the shear viscosities of methane are calculated in different external fields(on a hard wall, a solvophobic wall and in slit pores with different widths). In addition, the effects of temperature on the local density and viscosity are also considered. It shows that the effect of temperature on the shear viscosity is more obvious on solid surfaces. The calculation provides an approach to determine the viscosity under confined conditions, which is extremely significant in real industrial applications.

关键词： Viscosity Methane Statistical thermodynamics

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Hierarchical porous MgBO_2(OH) microspheres: Hydrothermal synthesis,thermal decomposition, and application as adsorbents for Congo red removal

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Chinese Journal of Chemical Engineering 2018年第7期26卷 1561-1569页

作者： Panpan Sun Liyuan Chen Lin Xu wancheng zhu Department of Chemical Engineering Qufu Normal University

A facile eco-friendly hydrothermal route （180 ℃, 12.0 h） has been developed for the first time to the uniform hierarchical porous MgBO2（OH） microspheres without the aid of any organic additive, surfactant or template, by using the abundant MgCl2·6H2O, H3BO3 and NaOH as the raw materials. The as-obtained porous microspheres exhibit a specific surface area of 94.752 mg·g-1, pore volume of 0.814 cm3.g-1, and ca. 84.0% of which have a diameter of 2.25-3.40 μm. The thermal decomposition of the porous MgBO2（OH） microspheres （650 ℃, 2.5 ℃. min-l） leads to the porous Mg2B2O5 rnicrospheres with well-retained morphology. When utilized as the adsorbents for the removal of CR from mimic waste water, the present porous MgBO2（OH） microspheres exhibit satisfactory adsorption capacity, with the maximum adsorption capacity qm of 309.1 mg-g-1, much higher than that derived from most of the referenced adsorbents. This opens a new window for the facile green hydrothermal synthesis of the hierarchical porous MgBO2（OH） microspheres, and extends the potential application of the 3D hierarchical porous metal borates as high-efficiency adsorbents for organic dyes removal.

关键词： Hierarchical porous microspheres Magnesium borate hydroxide Adsorption Congo red Hydrothermal

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Controllable hydrothermal synthesis of star-shaped Sr3Fe2（OH）12 assemblies and their thermal decomposition and magnetic properties

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Particuology 2016年第1期14卷 210-215页

作者： Heng Zhang Tingting Wang Xiuping Chen wancheng zhu Department of Chemical Engineering Qufu Normal University Qufu 273165 China

Pure phase star-shaped hydrogarnet Sr3Fe2（OH）12 assemblies were synthesized by a mild hydrothermal method （210℃, 12 h）, and the effects of the preparation conditions on the phase composition of the product were investigated. It was found that the impurity phases could be decreased or eliminated by increasing the molar ratio of Sr2＋ to Fe3＋, and that high temperatures favored the formation of Sr3 Fe2（OH）12 and reduced the concentration of CO32- -containing byproducts. The thermal decomposition of the star-shaped Sr3Fe2（OH）12 assemblies was examined, and the results showed that the dehydration process at higher temperatures is accompanied by the formation of SrFeO3-δ. Above 655 ℃, a solid state reaction between the SrFeO3-δ and Sr（OH）2 or SrCO3 results in the formation of Sr4Fe3O10-δ.The mag- netic properties of the as-synthesized Sr3Fe2（OH）12 and of samples calcined at different temperatures were assessed. A sample calcined at 575 ℃ exhibited greatly enhanced ferromagnetic properties, with a remanent magnetization of 1.28 emu/g and a coercivity of 4522.1 Oe at room temperature.

关键词： Hydrogarnet Hydrothermal Star-shaped Thermal decomposition Magnetic property

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One-pot hydrothermal synthesis of hierarchical porous manganese silicate microspheres as excellent Fenton-like catalysts for organic dyes degradation

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Nano Research 2022年第4期15卷 2977-2986页

作者： Yuyu Zheng Lihua Wang Liyun Zhang Heng Zhang wancheng zhu Department of Chemical Engineering Qufu Normal UniversityQufu 273165China

Towards bottlenecks demonstrated by typical Fenton-like catalysts in advanced oxidation processes(AOPs)for wastewater treatment,novel hierarchical porousMn^(2+)Mn_(6)^(3+)SiO_(12)(Mn_(7)SiO_(12),MSO-12)microspheres(specific surface area:434.90 m^(2)·g^(-1),pore volume:0.78 cm^(3)·g^(-1))were rationally designed and achieved via a simple one-pot hydrothermal method(150℃ and 12.0 h)without any pre-prepared templates or organic solvents,by using abundant MnCl_(2)·4H_(2)O and Na_(2)SiO_(3)·9H_(2)O as the basic raw *** MSO-12 microspheres are confirmed as high-efficiency Fenton-like catalysts for degradation of organic dyes(methylene blue(MeB),Rhodamine B(RhB),and methyl blue(MB))in the presence of H_(2)O_(2),with impressively high specific consumption amount of MeB(R=12.35 mg·g^(-1)·min^(-1))and extremely low leaching of Mn(Mnloss%=0.27%).Simultaneously,the synergetic effect of adsorption and degradation on the superior removal of MeB is *** excellent recycling performances,especially the satisfactory removal of MeB from the actual water bodies(e.g.,tap water and river water),as well as potential applications for degradation of RhB and MB enable the MSO-12 microspheres as a novel promising competitive candidate Fenton-like catalyst.

关键词： hierarchical porous manganese silicate microspheres Fenton-like catalysts degradation organic dyes

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High dispersion of heteropolyacid nanoparticles on hydrothermally Cs-modified three-dimensionally ordered macroporous SiO2 with excellent selectivity in methacrolein oxidation

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Chinese Journal of Chemical Engineering 2020年第11期28卷 2785-2791页

作者： Heng Zhang Junqi Liu Chenyuan Liu Tingting Wang wancheng zhu School of Chemistry and Chemical Engineering Qufu Normal UniversityQufu 273165China

Heteropolyacid nanoparticles(NPs)were supported on Cs-modified three-dimensionally ordered macroporous(3DOM)SiO2 and used as the catalyst for the oxidation of methacrolein(MAL)to methacrylic acid(MAA).Hydrothermal treatment and incipient wetness impregnation were employed respectively for the *** was found that hydrothermal Cs-modification of 3DOM SiO2 promoted the dispersion of the supported heteropolyacid,which showed an average particle size of 5.2 nm,much smaller than that(17.6 nm)on the Csmodified 3DOM SiO2 prepared by incipient wetness *** effects of hydrothermal treatment on the structure and catalytic performance of the catalyst were *** showed that the ion exchange between Cs+and the surface silanol groups on 3DOM SiO2 was promoted with the increase of the hydrothermal ***,Cs-modification helped the heteropolyacid to retain intact Keggin structure,inhibiting the formation of *** dispersed heteropolyacid NPs with enhanced structural stability exhibited excellent selectivity to MAA in the oxidation of MAL.

关键词： Catalyst support Heteropolyacid Nanoparticles Oxidation Methacrolein

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Effect of heterogeneity on occurrence of zonal disintegration around deep underground openings

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International Journal of Mining Science and Technology 2014年第6期24卷 859-864页

作者： Jia Peng zhu wancheng Zhang Shichao College of Resources and Civil Engineering Northeastern University

By utilizing the two numerical codes RFPA3 D and FLAC3 D, the effect of heterogeneity on failure mode and failure mechanism of rock around deep underground excavations under tri-axial stress is analyzed. It is found that zonal disintegration is a large scale shear-slip failure developed in deep surrounding rock mass under tri-axial stress, which is accompanied by a large amount of tensile failure. The distance between fractures and the number of fractures have a close correlation with the rock mass heterogeneity. With an increase of the homogeneity index of the rock mass, the distances between fractures decrease and the number of fractures increases. For an intact hard rock mass with relative high homogeneity, only failure mode characterized as v-shaped notches can be formed due to the intersection of intensively developed shear bands. None of the zonal disintegration can be formed due to the fact that with increasing homogeneity, the failure mechanism of rock mass is gradually dominated by shear failure rather than tensile failure.

关键词： Deep rock mass Heterogeneity Zonal disintegration Failure mode

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Experimental study on the effect of granular backfill with various gradations on the mechanical behavior of rock

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International Journal of Mining Science and Technology 2021年第5期31卷 889-899页

作者： Zhihua Le Qinglei Yu wancheng zhu Hongyuan Liu Tianhong Yang Center for Rock Instability and Seismicity Research Northeastern UniversityShenyang 110819China School of Engineering AMC the University of TasmaniaTAS 7005Australia

Backfilling is a common practice in the mining industry and the backfilling performance plays a significant role in supporting the surrounding rock *** evaluate the backfilling performance,an experimental apparatus has been developed to understand how backfill affects the compressive strength of sandstone specimens in the *** were selected to model the backfill and divided into six groups with different particle sizes using a set of standard *** backfilling pebbles with three types of particle size compositions were then produced,*** gradation,two adjacent gradations,and increasingly widening gradations.A series of compressive tests were carried out to study the mechanical behavior of the sandstone specimens confined by these *** effects of the gradations of the filled pebbles on the peak and residual compressive strengths were *** is found that the increasing amount of the compressive strength is over 10%in most cases,even up to 20%.Based on the experiment data,the increasing amount was also estimated theoretically under some assumptions and it further confirmed the experimental *** effects are closely related to the gradations of the filled pebbles except for their dense degree.

关键词： Granular backfill Dense degree Gradations Sandstone Compressive strength

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Platanus orientalis leaves based hierarchical porous carbon microspheres as high efficiency adsorbents for organic dyes removal

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Chinese Journal of Chemical Engineering 2020年第1期28卷 254-265页

作者： Xuezhen Jiang Panpan Sun Lin Xu Yingru Xue Heng Zhang wancheng zhu Department of Chemical Engineering Qufu Normal UniversityQufu 273165China

Water contamination caused by hazardous organic dyes has drawn considerable attention, among all of the techniques released, adsorption has been widely used, which however to a large degree is dependent on the development of high efficiency adsorbents. Waste biomass based porous carbon is becoming the new star class of adsorbents, and thus contribute more to the sustainable development of the society. In this work, for the first time to the best of our knowledge, abundant waste fallen Platanus orientalis leaves are employed as the raw material for hierarchical activated porous carbon(APC) microspheres via a mild hydrothermal carbonization(210 ℃,12.0 h) followed by one-step calcination(750 ℃, 1.0 h). The APC microspheres exhibit a specific surface area of 1355.53 m^2·g^-1 and abundant functional groups such as O—H and C=O. Furthermore, the APC microspheres are used as the adsorbents for removal of Rh B and MO, with the maximum adsorption capabilities of 557.06 mg·g^-1 and 327.49 mg·g^-1, respectively, higher than those of the most porous carbon originated from biomass. The adsorption rates rapidly approach to 98.2%(RhB) and 95.4%(MO) within 10 min. The adsorption data can be well fitted by Langmuir isotherm model and the pseudo-second-order kinetic model, meanwhile the intra-particle diffusion and Boyd models simultaneously indicate that the diffusion within the pores is the main rate-limiting step. Besides, the APC microspheres also demonstrate good recyclability, and may also be applied to other areas such as heterogeneous catalysis and energy storage.

关键词： Porous carbon microspheres Biomass Hydrothermal carbonization Platanus orientalis Organic dye Adsorption

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Facile room-temperature coprecipitation of uniform barium chlorapatite nanoassemblies as a host photoluminescent material

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Particuology 2018年第2期16卷 37-42页

作者： Peiyan Zhai Xiuping Chen Zhaoqiang Zhang Lin zhu Heng Zhang wancheng zhu Department of Chemical Engineering Qufu Normal University Shandong 273165 China

As an emerging host phosphor material, barium chlorapatite （Bas（PO4）3CI）, is attracting growing attention. However, rare earth-doped Bas（PO4）3CI phosphors have mainly been obtained via high temperature-based, energy-consuming techniques. In this contribution, we developed a straight- forward, facile room-temperature coprecipitation method in the presence of a specific amount of ethylenediaminetetraacetic acid disodium salt that provided Bas（PO4）3CI nanoparticles self-assembled to construct uniform Bas（PO4）3CI nanoassemblies （diameter： 80-120 nm） as well as rare earth Tb3＋- doped Bas（PO4）3CI：xTb3＋ nanophosphors. The nanoassemblies were transparent within the ultraviolet and visible spectral range. The Bas（PO4）3CI：xTb3＋ nanophosphors exhibited four emission peaks under 228-nm excitation, and the optimal doping amount of Tb3＋ was 4.0%. In contrast to traditional energy-consuming, high-temperature techniques, the facile room-temperature coprecipitation method developed here represents an attractive alternative route to obtain uniform Ba5（PO4）3CI nanoassemblies and Bas（PO4）3CI：xTb3＋ nanopbosphors that are candidate luminescent hosts.

关键词： Barium chlorapatite Nanoassemblies Phosphors Luminescence Room-temperature coprecipitation

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