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Analysis on damage and rheological characteristics of deep surrounding rock of shaft engineering

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Journal of Coal Science & Engineering(China) 2010年第1期16卷 29-34页

作者： YU Wei-jian ZHANG Yan School of Energy and Safety Engineering Hunan University of Science and Technology Xiangtan 411201 China Hunan Provincial Key Laboratory of Safe Mining Techniques of Coal Mines Hunan University of Science and Technology Xiangtan 411201 China School of Civil and Environmental Engineering University of Science and Technology Beijing Beijing 100083 China

According to the characteristics of deep engineering surrounding rock main shaft of No.3 mining district in Jinchuan, electron microscope scanning and rock mechanics test were adopted to analyze the damage features of rock. The software of FLAG3D and Burgers body （Kelvin-Maxwell model） were used to research on rheological theory, and rheological model was modified. The results indicate that the damage of rock mass is very serious, and the rheological characteristics also outstanding; rheological behavior of deep surrounding rocks of the shaft can be taken as superposition of transient and stable rheology; and there exist the most dangerous zone on 100 m higher than 1 063 m level, so it is necessity that works of monitor and corresponding reinforcement should strengthen.

关键词： shaft engineering deep surrounding rock rock damage rheological characteristics

rheological characteristics of aged asphalt binder

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Rheological characteristics of aged asphalt binder

rheological and Tribological characteristics of the Synthesized Lubricants Derived from Vegetable Oils

The 9th National Conference on Rheology

作者：刘聪慧吴少鹏刘全涛朱国军 Key Laboratory of Silicate Materials Science and Engineering of Ministry of Education Wuhan University of Technology

Different aging levels (RTFOT,PAV-10h,PAV-20h and PAV-30 h) of asphalt binders with various mass ratios of mineral powder to asphalt (0,0.4,0.8,1.2,1.6,2.0) were used to investigate the rheological properties of aged asphalt binders with respect to their short and long terms aging *** test,dynamic shear test and creep test were *** test results indicate that the viscosity of aged asphalt hinder increases sharply with the extension of aging *** shear modulus of aged asphalt increases,which indicates that the stiffness of asphalt binders can *** phase angle for aged asphalt binders reduces,which indicates that the elastic portion for viscoelastic property of asphalt binders increases.|G|·sin δ increases after aging procedure which means that the fatigue resistance becomes *** creep test results show that creep strain curves varies remarkably for virgin and aged asphalt *** total strain during loading period and the permanent strain decreases significantly for aged asphalt binders,which implies that the elastic portion increases and the viscous portion decreases.

关键词： aged asphalt binder rheological characteristics viscoelastic property mass ratio of mineral powder to asphalt

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cnki会议

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Journal of Shanghai University(English Edition) 2005年第5期9卷 462-465页

作者：王彬陶德华 School of Electromechanical Engineering and Automation Shanghai University Shanghai 200072 P.R.China School of Environmental and Chemical Engineering Shanghai University Shanghai 200072 P.R.China

The double bonds in the vegetable oils can be conjungated and Diels-Alder react when they are heated in the existence of the catalyst. The percent of the double bond will decrease and the oxidative stability of the vegetable oils can be ameliorated. Dimmer acid can react with different carbon chain length of alcohols to form dimmer acid esters. A series of dimmer acid esters were synthesized and their rheological characteristics （viscosity, viscosity index, pour point） and tribological characteristics （the coefficient of friction at different load, the characteristic of extreine pressure （ PB ）, the wear scare diameter （ D30min^196N ） were evaluated and analyzed. The results showed that the characteristics of Di-iso-octanol dimmer acid ester were the best among the synthesized dimmer esters. It＇ s a lubricant with good properties（the viscosity is 94.5 mm^2/s, the viscosity index is high up to 141 and the pour point is - 49℃ ）. It is a kind of newly interesthing ester type lubricant. Its rheological and tribological characteristics are even better than those of the slap-up synthesized lubricant--pentaerythritol esters （C7-9 acidate）. The FT-IR spectrophotometer was used to analyze the structure of the synthetic esters. Their IR spectra are the same as the typical IR spectrum of ester. The test indicated that Di-iso-octanol dimmer acid ester could be used as a kind of base lubricant with excellent quantity.

关键词： vegetable oils dimmer acid synthetic ester rheological characteristics tribological characteristics.

Time-dependent safety of lining structures of circular tunnels in weak rock strata

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International Journal of Mining Science and Technology 2022年第2期32卷 323-334页

作者： Baoguo Liu Yu Song Zhaofei Chu School of Civil Engineering Beijing Jiaotong UniversityBeijing 100044China School of Civil Engineering Wuhan UniversityWuhan 430072China

Following tunnel excavation and lining completion,fractured surrounding rock deforms gradually over time;this results in a time-dependent evolution of the pressure applied to the lining structure by the surrounding ***,the safety of the tunnel lining in weak strata is strongly correlated with *** this study,we developed an analytical method for determining the time-dependent pressure in the surrounding rock and lining structure of a circular tunnel under a hydrostatic stress *** the proposed method,the stress–strain relationship of the fractured surrounding rock is assumed to conform to that of the Burgers viscoelastic component,and the lining structure is assumed to be an *** on these assumptions,the viscoelastic deformation of the surrounding rock,the elastic deformation of the lining structure,and the coordinated deformation between the surrounding rock and lining structure were *** proposed analytical method,which employs a time-dependent safety coefficient,was subsequently used to estimate the durability of the lining structure of the Foling Tunnel in *** derived attenuation curve of the safety coefficient with respect to time can assist engineers in predicting the remaining viable life of the lining *** existing analytical methods,the method derived in this study considers the time dependency of the interaction between the surrounding rock and tunnel lining;hence,it is more suitable for the evaluation of lining lifetime.

关键词： Tunnel lining Surrounding rock pressure rheological characteristics Weak rock strata Time-dependent safety

Improving slurryability, rheology,and stability of slurry fuel from blending petroleum coke with lignite

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Petroleum Science 2015年第1期12卷 157-169页

作者： Jun-Hong Wu Jian-Zhong Liu Yu-Jie Yu Rui-Kun Wang Jun-Hu Zhou Ke-Fa Cen State Key Laboratory of Clean Energy Utilization Zhejiang University

Petroleum coke and lignite are two important fossil fuels that have not been widely used in China. Petroleum coke-lignite slurry （PCLS）, a mixture of petro- leum coke, lignite, water, and additives, efficiently utilizes the two materials. In this study, we investigate the effects of the proportion （7） of petroleum coke on slurryability, rheo- logical behavior, stability, and increasing temperature characteristics of PCLSs. The results show that the fixed- viscosity solid concentration （COo） increases with increasing 7. The ~Oo of lignite-water slurry （LWS, ~ = 0） is 46.7 %, compared to 71.3 % for the petroleum coke-water slurry （PCWS, c~ --- i00 %）, while that of PCLS is in between the two values. The rheological behavior of PCLS perfectly fits the power-law model. The PCWS acts as a dilatant fluid. As decreases, the slurry behaves first as an approximate Newtonian fluid, and then turns into a pseudo-plastic fluid that exhibits shear-thinning behavior. With increasing ct, the rigid sedimentation and water separation ratio （WSR） increase, indicating a decrease in the stability of PCLS. When α is 60-70 %, the result is a high-quality slurry fuel for industrial applications, which has high slurryability （ω0 = 57-60 %）, good stability （WSR 〈 2 %）, and superior pseudo-plastic behavior （n = 0.9）.

关键词： Petroleum coke Lignite Coal-water slurry rheological characteristics Slurry stability

Numerical Study on Interaction Between Two Bubbles Rising Side by Side in CMC Solution

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Chinese Journal of Chemical Engineering 2013年第7期21卷 705-713页

作者：范文元尹晓红 School of Chemistry and Chemical Engineering Tianjin University of Technology Tianjin 300384 China

A numerical simulation was performed to investigate the interaction of two bubbles rising side by side in shear-thinning fluid using volume of fluid （VOF） method coupled with continuous surface force （CSF） method. By considering rheological characteristics of fluid, this approach was able to accurately capture the deformation of bubble interface, and validated by comparing with the experimental results. The rising of bubble pairs with different configurations, including horizontal alignment and oblique alignment, was simulated by the method. The influences of the bubble initial distance and the bubble alignment were studied by analyzing the bubble deformation, rising paths and flow fields surrounding bubbles. The results indicate that within certam mltlal bubble spacing of S = 3.3 （S＊ = SI/D, SI initial distance between bubbles, and D bubble diameter）, the dynamic interaction between two bub- bles aligned horizontally shows repulsive effect that decreases with the increase of initial bubble spacing, but weakens to certain degree by the shear-thinning properties of fluid. However, the interaction between two bubbles aligned obliquely presents a repulsive effect for the small angle involved but an attractive impact for the large one, which is vet strengthened by the rheological characteristics of fluid.

关键词： bubble pairs interaction shear-thinning volume of fluid method rheological characteristics

SIMULATION OF MICROSTRUCTURE AND RHEOGICAL PROPERTIES OF SURFACTANT SOLUTION

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Transactions of Nanjing University of Aeronautics and Astronautics 2007年第3期24卷 232-238页

作者：熊贤鹏刘卫华昂海松高秀峰魏进家南京航空航天大学航空宇航学院西安交通大学动力工程多相流国家重点实验室

The Brownian dynamics （BD） simulation of a dilute surfactant solution is conducted in a steady shear flow. The rodlike micelle is assumed as a rigid rod composed of lined-up beads. A novel intercluster potential model is introduced for describing the interactions between, micelles. In the model, the Lennard-Jones and the soft-sphere potentials are used as inter-bead potentials for end-end and interior-interior beads, respectively. The micelles are combined at their ends to form a network structure at lower shear rates and are disconnected to become more and more parallel to the shear flow direction with increasing shear rate. The change of micellar microstructures with the variation of the shear rate results in shear thinning characteristics of the computed shear viscosities and first normal stress difference coefficients. The effects of surfactant solution concentration on the micellar structures and rheological properties are also investigated. Results show that the shear viscosities and the first normal stress difference coefficients increase with increasing the viscosity of the surfactant solution.

关键词： surfactant microstructure rodlike micelle Brownian dynamics simulation rheological characteristics