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Numerical investigation of geostress influence on the grouting reinforcement effectiveness of tunnel surrounding rock mass in fault fracture zones

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Journal of rock mechanics and Geotechnical Engineering 2024年第1期16卷 81-101页

作者： Xiangyu Xu Zhijun Wu Lei Weng Zhaofei Chu Quansheng Liu Yuan Zhou The Key Laboratory of Safety for Geotechnical and Structural Engineering of Hubei Province School of Civil EngineeringWuhan UniversityWuhan430072China Wuhan University Shenzhen Research institute Shenzhen518057China State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan UniversityWuhan430072China institute of rock and Soil mechanics Chinese Academy of SciencesWuhan430071China

Grouting is a widely used approach to reinforce broken surrounding rock mass during the construction of underground tunnels in fault fracture zones,and its reinforcement effectiveness is highly affected by *** this study,a numerical manifold method(NMM)based simulator has been developed to examine the impact of geostress conditions on grouting reinforcement during tunnel *** develop this simulator,a detection technique for identifying slurry migration channels and an improved fluid-solid coupling(FeS)framework,which considers the influence of fracture properties and geostress states,is developed and incorporated into a zero-thickness cohesive element(ZE)based NMM(Co-NMM)for simulating tunnel ***,to simulate coagulation of injected slurry,a bonding repair algorithm is further proposed based on the ZE *** verify the accuracy of the proposed simulator,a series of simulations about slurry migration in single fractures and fracture networks are numerically reproduced,and the results align well with analytical and laboratory test ***,these numerical results show that neglecting the influence of geostress condition can lead to a serious over-estimation of slurry migration range and reinforcement *** validations,a series of simulations about tunnel grouting reinforcement and tunnel excavation in fault fracture zones with varying fracture densities under different geostress conditions are *** on these simula-tions,the influence of geostress conditions and the optimization of grouting schemes are discussed.

关键词： Numerical manifold method(NMM) Grouting reinforcement Geostress condition Fault fracture zone Tunnel excavation

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Shear behavior and off-fault damage of saw-cut smooth and tension-induced rough joints in granite

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Journal of rock mechanics and Geotechnical Engineering 2024年第4期16卷 1216-1230页

作者： Fanzhen Meng Feili Wang Louis Ngai Yuen Wong Jie Song Muzi Li Chuanqing Zhang Liming Zhang College of Science Qingdao University of TechnologyQingdao266033China Department of Earth sciences The University of Hong KongPokfulamHong KongChina State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan430071China Cooperative Innovation Center of Engineering Construction and Safety Shandong Peninsula Blue Economic Zone Qingdao266033China

The damage of rock joints or fractures upon shear includes the surface damage occurring at the contact asperities and the damage beneath the shear surface within the host *** latter is commonly known as off-fault damage and has been much less investigated than the surface *** main contribution of this study is to compare the results of direct shear tests conducted on saw-cut planar joints and tension-induced rough granite joints under normal stresses ranging from 1 MPa to 50 *** shear-induced off-fault damages are quantified and compared with the optical microscope *** results clearly show that the planar joints slip stably under all the normal stresses except under 50 MPa,where some local fractures and regular stick-slip occur towards the end of the *** post-peak stress drop and stick-slip occur for all the rough *** residual shear strength envelopes for the rough joints and the peak shear strength envelope for the planar joints almost *** root mean square(RMS)of asperity height for the rough joints decreases while it increases for the planar joint after shear,and a larger normal stress usually leads to a more significant decrease or increase in ***,the extent of off-fault damage(or damage zone)increases with normal stress for both planar and rough joints,and it is restricted to a very thin layer with limited micro-cracks beneath the planar joint *** comparison,the thickness of the damage zone for the rough joints is about an order of magnitude larger than that of the planar joints,and the coalesced micro-cracks are generally inclined to the shear direction with acute *** findings obtained in this study contribute to a better understanding on the frictional behavior and damage characteristics of rock joints or fractures with different roughness.

关键词： Planar joint Rough joint Shear behavior Off-fault damage Micro-cracks

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Analytical solution to incident angle quasi-phase-matching engineering for second harmonic generation in a periodic-poled lithium niobate crystal

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Chinese Physics B 2024年第2期33卷 115-123页

作者：洪丽红邱雅婷李晓霓陈宝琴李志远 State Key Laboratory of High Field Laser Physics Shanghai Institute of Optics and Fine MechanicsChinese Academy of SciencesShanghai 201800China School of Physics and Optoelectronics South China University of TechnologyGuangzhou 510640China

Phase matching or quasi-phase matching(QPM)is of significant importance to the conversion efficiency of second harmonic generation(SHG)in artificial nonlinear crystals like lithium niobate(LN)crystal or microstructured nonlinear crystals like periodic-poled lithium niobate(PPLN)*** this paper,we propose and show that the incident angle of pump laser light can be harnessed as an alternative versatile tool to engineer QPM for high-efficiency SHG in a PPLN crystal,in addition to conventional means of period adjusting or temperature tuning.A rigorous model is established and analytical solution of the nonlinear conversion efficiency under the small and large signal approximation theory is obtained at different incident *** variation of phase mismatching and walk-off length with incident angle or incident wavelength are also *** simulations for a PPLN crystal with first order QPM structure are used to confirm our theoretical predictions based on the exact analytical solution of the general large-signal *** results show that the narrow-band tunable SHG output covers a range of 532 nm–552.8 nm at the ideal incident angle from 0°to 90°.This theoretical scheme,fully considering the reflection and transmission at the air-crystal interface,would offer an efficient theoretical system to evaluate the nonlinear frequency conversion and help to obtain the maximum SHG conversion efficiency by selecting an optimum incident wavelength and incident angle in a specially designed PPLN crystal,which would be very helpful for the design of tunable narrow-band pulse nanosecond,picosecond,and femtosecond laser devices via PPLN and other microstructured LN crystals.

关键词： nonlinear frequency conversion transmission reflection lithium niobate

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Impact of mica on geotechnical behavior of weathered granitic soil using macro and micro investigations

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Journal of rock mechanics and Geotechnical Engineering 2024年第6期16卷 2250-2266页

作者： Xianwei Zhang Xinyu Liu Haodong Gao Gang Wang Ran An Zhu Liang State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan430071China School of Civil and Hydraulic Engineering Huazhong University of Science and TechnologyWuhan430074China College of Urban Construction Wuhan University of Science and TechnologyWuhan430065China University of Chinese academy of sciences Beijing100049China Guangzhou Urban Planning&Design Survey Research institute Guangzhou510000China Guangdong Enterprise Key Laboratory for Urban Sensing Monitoring and Early WarningGuangzhou510000China

The micaceous weathered granitic soil(WGS)is frequently encountered in civil engineering worldwide,unfortunately little information is available regarding how mica affects the physico-mechanical behaviors of *** study prepares reconstituted WGS with different mica contents by removing natural mica in theWGS,and then mixes it with commercial mica *** geotechnical behavior as well as the microstructures of the mixtures are *** addition of mica enables the physical indices of WGS to be specific combinations of coarser gradation and high permeability but high Atterberg ***,high mica content in WGS was found to be associated with undesirable mechanical properties,including increased compressibility,disintegration,and swelling potential,as well as poor compactability and low effective frictional *** analysis indicates that the influence of mica on the responses of mixtures originates from the intrinsic nature of mica as well as the particle packing being formed *** exists in the mixture as stacks of plates that form a spongy structure with high compressibility and swelling *** among the plates give the soil high water retention and high Atterberg *** pores are also generated by soil particles with bridging packing,which enhances the permeability and water-soil interactions upon *** study provides a microlevel understanding of how mica dominates the behavior of WGS and provides new insights into the effective stabilization and improvement of micaceous soils.

关键词： Weathered granitic soil(WGS) Mica Microstructure Physical properties Mechanical properties Mechanism

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Highly strengthening and toughening biomimetic ceramic structures fabricated via a novel coaxially printing

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Journal of Advanced Ceramics 2024年第4期13卷 403-412页

作者： Kunkun Song Shengda Yang Ningqi Shao Yantang Zhao Peng He Yongfeng Wei Hengzhong Fan Yongsheng Zhang Qiangqiang Zhang State Key Laboratory of Solid Lubrication Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhou 730000China School of Civil Engineering and mechanics Lanzhou UniversityLanzhou 730000China Key Laboratory of mechanics on Disaster and Environment in Western China(Lanzhou University) Ministry of EducationLanzhou 730000.China

Additive manufacturing technology,by manipulating and emulating inherent multiscale,multi-material,and multifunctional structures found in nature,has created new opportunities for constructing heterogeneous structures associated with special properties and achieving ultra-high mechanical performance and reliability in ceramic composite *** this study,we have developed an innovative fabrication method designated as coaxial 3D printing for the synchronous construction of two constituents into ceramic composites with a tooth enamel biomimetic ***,the stiff silicate and flexible epoxy served as a strengthening bridge and toughening layer,*** method differed from the traditional approach of randomly dispersing reinforcing components within a ceramic *** allowed for the direct creation of an internally effective three-dimensional reinforcement network structure in ceramic *** process facilitated synergistic deformation and simultaneous enhancement of multiple materials and hierarchical *** to the uniform distribution of internal stress and effective block of microcrack propagation,the biomimetically structured silicate/epoxy ceramic composite has demonstrated much significant enhancement in mechanical properties,includingcompressive strength(48.8±3.12MPa),flexuralstrength(10.39±1.23MPa),andflexuraltoughness(218.7±54.6kJ/m^(3)),which was 0.5,2.1,and 47.5 times as high as those of the intrinsic brittle silicate ceramics,***-situ characterization and multiscale finite element simulation of microstructural evolution during three-point bending deformation further validated multiple-step features of the fracture process(silicate bridge fracture,interface detachment,epoxy extraction,and rupture),which benefited from interpenetrating structural features achieved by coaxial printing to accomplish with the complex propagating routines of the crack deflection in silicate ceramic *** coaxia

关键词： coaxial 3D printing silicate ceramic composites enamel biomimetic microstructure strengthening bridge tougheninglayer crackdeflection

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Aseismic performances of constrained damping lining structures made of rubber-sand-concrete

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Journal of rock mechanics and Geotechnical Engineering 2024年第5期16卷 1522-1537页

作者： Xiancheng Mei Qian Sheng Jian Chen Zhen Cui Jianhe Li Chuanqi Li Daniel Dias State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan430071China University of Chinese academy of sciences Beijing100049China Key Laboratory of Water Grid Project and Regulation of Ministry of Water Resources Changjiang Institute of SurveyPlanningDesign and ResearchWuhan430010China Laboratory 3SR CNRS UMR 5521Grenoble Alpes UniversityGrenoble38000France School of Automotive and Transportation Engineering Hefei University of TechnologyHefei23009China

Flexible damping technology considering aseismic materials and aseismic structures seems be a good solution for engineering *** this study,a constrained damping structure for underground tunnel lining,using a rubber-sand-concrete(RSC)as the aseismic material,is *** aseismic performances of constrained damping structure were investigated by a series of hammer impact *** damping layer thickness and shape effects on the aseismic performance such as effective duration and acceleration amplitude of time-domain analysis,composite loss factor and damping ratio of the transfer function analysis,and total vibration level of octave spectrum analysis were *** hammer impact tests revealed that the relationship between the aseismic performance and damping layer thickness was not linear,and that the hollow damping layer had a better aseismic performance than the flat damping layer *** aseismic performances of constrained damping structure under different seismicity magnitudes and geological conditions were *** effects of the peak ground acceleration(PGA)and tunnel overburden depth on the aseismic performances such as the maximum principal stress and equivalent plastic strain(PEEQ)were *** numerical results show the constrained damping structure proposed in this paper has a good aseismic performance,with PGA in the range(0.2-1.2)g and tunnel overburden depth in the range of 0-300 m.

关键词： Constrained damping structure Aseismic performance Hammer impact tests Damping layer Peak ground acceleration Overburden depth

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Upconversion luminescence and temperature sensing performance of Er^(3+) ions doped self-activated KYb(MoO_(4))_(2) phosphors

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Journal of Rare Earths 2024年第8期42卷 1507-1513,I0004页

作者： Ye Tong Wenpeng Liu Shoujun Ding School of Microelectronics and Data Science Anhui University of TechnologyMaanshan243002China Advanced Laser Technology Laboratory of Anhui Province Hefei230037China Anhui institute of Optics and Fine mechanics Chinese Academy of SciencesHefei230031China

In this work,a series of self-activated KYb(MoO_(4))_(2) phosphors with various x at% Er^(3+) doping concentrations(x=0.5,1,3,5,8,10,15) was synthesized by the solid-state reaction *** phase structure of the as-prepared samples was analyzed by X-ray diffraction(XRD),XRD Rietveld refinement and Fourier transform infrared(FT-IR) *** as-prepared samples retain the orthorhombic structure with space group of Pbcn even Er^(3+) doping concentration up to 15 at%.High-purity upconversion(UC) green emission with green to red intensity ratio of 55 is observed from the as-prepared samples upon the excitation of 980 nm semiconductor laser and the optimum doping concentration of Er^(3+) ions in the self-activated KYb(MoO_(4))_(2) host is revealed as 3 at%.The strong green UC emission is confirmed as a two-photon process based on the power-dependent UC *** addition,the fluorescence intensity ratios(FIRs) of the two thermally-coupled energy levels,namely ^(2)H_(11/2) and ^(4)S_(3/2).of Er^(3+) ions were investigated in the temperature region 300-570 K to evaluate the optical temperature sensor behavior of the *** maximum relative sensitivity(S_(R)) is determined to be 0.0069 K^(-1) at300 K and the absolute sensitivity(S_(A)) is determined to be 0.0126 K^(-1) at 300 *** S_(A) of self-activated KYb(MoO_(4))2:Er^(3+)is almost twice that of traditional KY(MoO_(4))2:Er^(3+)/Yb^(3+)codoping *** results demonstrate that Er^(3+) ions doped self-activated KYb(MoO_(4))2 phosphor has promising application in visible display,trademark security and optical temperature sensors.

关键词： Er^(3+)ions doped KYb(MoO_(4))_(2) Self-activated phosphors Upconversion luminescence Solid-state reaction method Optical temperature sensors Rare earths

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High recorded color rendering performance of single-structured Ce,Mn:Y_(3)(Al,Sc)_(2)Al_(3)O_(12)phosphor ceramics for high-power white LEDs/LDs

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Journal of Advanced Ceramics 2024年第6期13卷 810-820页

作者： Xuanchu Liu Congcong Yang Yanbin Li Chang Min Jian Kang Tianyuan Zhou Chunming Zhou Chaofan Shi Cen Shao Bingheng Sun Wieslaw Strek Hao Chen Le Zhang Jiangsu Key Laboratory of Advanced Laser Materials and Devices School of Physics and Electronics EngineeringJiangsu Normal UniversityXuzhou 221116China Jiangsu Xiyi Advanced Materials Research institute of Industrial Technology Xuzhou 221400China Xuzhou EAGLED Technology Co. Ltd.Xuzhou 221116China Xuzhou Kangna Advanced Materials Technology Co. Ltd.Xuzhou 221116China Shanghai institute of Optics Fine mechanics Chinese Academy of SciencesShanghai 201800China institute of Low Temperature and structure Research Polish Academy of SciencesWroclaw 50-422Poland State Key Laboratory of Crystal Materials Shandong UniversityJinan 250100China

Achieving a high color rendering index(CRI)and luminous stability in single-structured Ce:Y_(3)Al_(5)O_(12)(Ce:YAG)phosphor ceramics(PCs)is crucial for high-power white light-emitting diodes or laser diodes(LEDs/LDs).However,cyan valleys and insufficient amounts of the red component in the Ce:YAG emission spectra significantly limit their real *** this work,a series of Ce,Mn:Y_(3)(Al,Sc)_(2)Al_(3)O_(12)(Ce,Mn:YSAG)PCs were fabricated by vacuum sintering,and efficient spectral regulation was realized for full-color *** cyan valley was filled by the blueshifted emission peak of Ce^(3+)via Sc^(3+)*** orange‒red emission at approximately 580 nm was effectively supplemented via Mn^(2+)*** particular,CRI of Ce,Mn:YSAG increased from 56.4 to 85.8,a 52%increase compared with that of Ce:YAG under high-power LED excitation,and the operating temperature was stable at approximately 50℃for long working ***,CRI of 80.9 could still be obtained for PC-based white *** results indicated that Ce,Mn:YSAG PC,which has excellent CRI and luminous stability,is an extremely promising color convertor for high-power white LEDs/LDs.

关键词： color rendering index(CRI) color converter Ce:Y_(3)Al_(5)O_(12)(Ce:YAG)phosphor ceramics(PCs) high-power white light-emitting diodes or laser diodes(LEDs/LDs) luminous stability

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Spectral-interferometry-based diff-iteration for high-precision micro-dispersion measurement

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Photonics Research 2024年第6期12卷 1362-1370页

作者： WEI DU JINGSHENG HUANG YANG WANG MAOZHONG ZHAO JUAN LI JUNTAO HE JINDONG WANG WENFU ZHANG TAO ZHU Key Laboratory of Optoelectronic Technology&System(Ministry of Education) Chongqing UniversityChongqing 400044China State Key Laboratory of Transient Optics and Photonics Xi’an Institute of Optics and Precision MechanicsChinese Academy of SciencesXi’an 710119China

Precise measurement of micro-dispersion for optical devices(optical fiber,lenses,etc.)holds paramount significance across domains such as optical fiber communication and dispersion interference ***,due to its complex system,complicated process,and low reliability,the traditional dispersion measurement methods(interference,phase shift,or time delay methods)are not suitable for the accurate measurement of micro-dispersion in a wide spectral ***,we propose a spectral-interferometry-based diff-iteration(SiDi)method for achieving accurate wide-band micro-dispersion *** an optical frequency comb,based on the phase demodulation of the dispersion interference spectrum,we employ the carefully designed SiDi method to solve the dispersion curve at any position and any *** approach is proficient in precisely measuring micro-dispersion across a broadband spectrum,without the need for cumbersome wavelength scanning processes or reliance on complex high-repetition-rate combs,while enabling adjustable *** efficacy of the proposed method is validated through simulations and *** employed a chip-scaled soliton microcomb(SMC)to compute the dispersion curves of a 14 m single-mode fiber(SMF)and a 0.05 m *** to a laser interferometer or the theoretical value given by manufacturers,the average relative error of refractive index measurement for single-mode fiber(SMF)reaches 2.8×10^(-6) and for glass reaches 3.8×10^(-6).The approach ensures high precision,while maintaining a simple system structure,with realizing adjustable resolution,thereby propelling the practical implementation of precise measurement and control-dispersion.

关键词： interferometer dispersion iteration

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软弱富水地层承压水对掌子面极限支护力的影响（英文）

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Journal of Central South University 2024年第08期 2844-2859页

作者：李运发伍国军陈卫忠袁敬强霍梦喆 State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil Mechanics Chinese Academy of Sciences University of Chinese academy of sciences

软土地层盾构隧道前方存在承压含水层会对掌子面的稳定性构成重大威胁，因此，考虑承压水对掌子面极限支护力的影响至关重要。首先，采用有限元数值软件分析了不同承压水头、隔水层厚度、埋深、盾构直径、土体黏聚力以及内摩擦角条件下... 详细信息

软土地层盾构隧道前方存在承压含水层会对掌子面的稳定性构成重大威胁，因此，考虑承压水对掌子面极限支护力的影响至关重要。首先，采用有限元数值软件分析了不同承压水头、隔水层厚度、埋深、盾构直径、土体黏聚力以及内摩擦角条件下掌子面的失稳模式，并统计了各个条件下的极限支护力。随后，结合上述影响因素，采用多元线性回归方法，推导出计算掌子面极限支护力的简明公式。最后，结合事故案例，将本文提出公式的结果与以往传统理论解对比，验证了其有效性。分析得出以下结论：1)承压水影响软土地层隧道掌子面的失稳模式，当承压水头较小时，掌子面前方水力梯度也较小，塑性区失稳形状呈螺旋状，随着水头升高，螺旋倾角增大，失稳形状向圆柱形转变。2)统计各工况下的结果发现，隧道掌子面稳定所需的极限支护力随承压水的水头、隧道尺寸和埋深近似线性增加，与隔水层厚度、土体内聚力和内摩擦角成反比。3)通过工程案例研究分析，本文公式结果与传统理论方法的结果吻合较好，验证了本文所提公式的合理性。此外，所提出的方程克服了传统理论方法在考虑不透水层厚度变化影响方面的局限性，可以准确描绘盾构隧道掘进过程中保持隧道工作面稳定性所需的极限支护力的动态变化，从而更好地反映工程实际。

关键词：软弱富水地层承压含水层极限支护力有限元法多元线性回归

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