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Removal of Cd(Ⅱ)from dilute aqueous solutions by complexation–ultrafiltration using rotating disk membrane and the shear stability of PAA–Cd complex
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作者 Liang Chen Yunren Qiu 《中国化学工程学报:英文版》 SCIE EI CAS CSCD 2019年第3期519-527,共9页
Removal of cadmium(Ⅱ)ions from dilute aqueous solutions by complexation–ultrafiltration using rotating disk membrane was investigated.Polyacrylic acid sodium(PAAS)was used as complexation agent,as key factors of com... Removal of cadmium(Ⅱ)ions from dilute aqueous solutions by complexation–ultrafiltration using rotating disk membrane was investigated.Polyacrylic acid sodium(PAAS)was used as complexation agent,as key factors of complexation,pH and the mass ratio of PAAS to Cd2+(P/M)were studied,and the optimum complexation–ultrafiltration conditions were obtained.The effects of rotating speed(n)on the stability of PAA–Cd complex was studied with two kinds of rotating disk,diskⅠ(without vane)and diskⅡ(with six rectangular vanes)at a certain range of rotating speed.Both of the rejection could reach 99.7%when n was lower than 2370 r·min-1 and 1320 r·min-1,for disk I and diskⅡ,respectively.However,when rotating speed exceeds a certain value,the critical rotating speed(nc),the rejection of Cd(Ⅱ)decreases greatly.The distribution of form of cadmium on the membrane was established by the membrane partition model,and the critical shear rate(γc),the smallest shear rate at which the PAA–Cd complex begins to dissociate,was calculated based on the membrane partition model and mass balance.The critical shear rates(γc)of PAA–Cd complex were 5.9×104 s-1,1.01×105 s-1,and 1.31×105 s-1 at pH=5.0,5.5,and 6.0,respectively.In addition,the regeneration of PAAS was achieved by shear induced dissociation and ultrafiltration. 展开更多
关键词 Complexation–ultrafiltration MEMBRANE Regeneration SHEAR stability Critical SHEAR rate SHEAR induced dissociation
A new model for evaluating the dynamic shear strength of rocks based on laboratory test data for earthquake-resistant design 预览
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作者 Tetsuji Okada Tomohiro Naya 《岩石力学与岩土工程学报:英文版》 CSCD 2019年第5期979-989,共11页
The dynamic shear strength of rocks is required for the earthquake-resistant design of nuclear power plants in Japan.This research aims to propose a mathematical model for estimating the dynamic strength and to valida... The dynamic shear strength of rocks is required for the earthquake-resistant design of nuclear power plants in Japan.This research aims to propose a mathematical model for estimating the dynamic strength and to validate the model.Two different types of specimens were prepared for the model validation,and the monotonic and cyclic loading tests were conducted to obtain the mathematical model parameters.Subsequently,multistep cyclic loading tests were performed,followed by simulations using the mathematical model.The test results demonstrated that the dynamic shear strength exceeded the static shear strength,which agreed with previous researches.Furthermore,the dynamic shear strength calculated using the mathematical model was generally consistent with that obtained from the experimental data. 展开更多
关键词 DYNAMIC SHEAR STRENGTH Static SHEAR STRENGTH CYCLIC loading Strain rate Fatigue Mathematical model
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Shear behavior of ultrafine magnetite tailings subjected to freeze-thaw cycles 预览
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作者 Chong Wei Derek B.Apel Yunhai Zhang 《矿业科学技术学报:英文版》 CSCD 2019年第4期609-616,共8页
To study the shear behavior of the ultrafine magnetite tailings subjected to freeze-thaw cycles,unconsolidated-undrained shear tests were conducted on ultrafine-grained tailings that were subjected to 1-11 cycles of f... To study the shear behavior of the ultrafine magnetite tailings subjected to freeze-thaw cycles,unconsolidated-undrained shear tests were conducted on ultrafine-grained tailings that were subjected to 1-11 cycles of freeze-thaw and defined as a type of clayey silt under confining pressures of 100,200,and 300 kPa.Taking the number of freeze-thaw cycles,cooling temperature,initial dry density,and moisture content as the four main influencing factors of shear behavior of the tailings samples,the shear stress-strain curve,compression modulus,failure strength,cohesion,and internal friction angle were measured.The results show that the freeze-thaw cycle has an obvious weakening effect on the shear behavior of the tailings material,and the shear mechanical parameters are affected by a combination of confining pressure,freeze-thaw cycle condition,and initial physical-mechanical properties of the tailings samples.Through the microstructural analysis of the tailings samples subjected to freeze-thaw cycles,it shows that the freeze-thaw cycle mainly affects the porosity,bound water,and arrangement of the tailings particles.Subsequently,the macroscopic changes in shear strength indexes emerge,and then the stability of the tailings dam will decrease. 展开更多
关键词 Ultrafine magnetite tailings(UMT) Freeze-thaw cycle Shear behavior Triaxial shear test
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Bonding Properties of Aluminum Alloy Plate and Concrete 预览
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作者 Haoran Wang 《智能建筑研究》 2019年第1期42-53,共12页
Aluminum alloy material has the advantages of high strength, good deformation performance, corrosion resistance, etc. it is an ideal material for steel reinforced concrete structure reinforcement engineering in coasta... Aluminum alloy material has the advantages of high strength, good deformation performance, corrosion resistance, etc. it is an ideal material for steel reinforced concrete structure reinforcement engineering in coastal erosion environment. The cohesive property of aluminum alloy plate and concrete is the key problem whether the aluminum alloy plate and steel bar concrete beam can work together. Based on this, the bonding performance between aluminum alloy plate and concrete is tested and theoretically studied. Considering the influence of strength of mixed concrete, width and thickness of aluminum alloy plate, bonding length and interface treatment on the bonding performance of aluminum alloy plate and concrete block, a set of specimen fixing device was designed, and 105 bonded specimens of aluminum alloy plate and mixed concrete prism were tested in-plane single shear by universal testing machine. According to the test results and theoretical analysis, the typical characteristics of cohesive failure, shear stress distribution curve and cohesive slip curve of aluminum alloy plate and mixed concrete are obtained. The research shows that there are two types of failure of the specimen: interfacial peeling failure and mixed concrete layer peeling failure. Interface treatment has an important influence on the bonding performance. The specimens without roughening the bonding interface have interface peeling and breaking, while other specimens have concrete layer peeling and breaking. As the strength of the mixed concrete increases and the width and thickness of the aluminum alloy plate decrease, the cohesiveness can be improved. There is an effective adhesive length. When the adhesive length is greater than the effective adhesive length, increasing the adhesive length does not increase the ultimate load of the connection. 展开更多
关键词 Aluminum alloy PLATE Adhesion property IN-PLANE single SHEAR test SHEAR stress STRIPPING failure
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Effects of water content on the shear behavior and critical state of glacial till in Tianmo Gully of Tibet, China
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作者 ZHOU Gordon G.D. CHEN Lei-lei +2 位作者 MU Qing-yi CUI Kahlil Fredrick E. SONG Dong-ri 《山地科学学报:英文版》 SCIE CSCD 2019年第8期1743-1759,共17页
Glacial tills are widely distributed in Tibet, China, and are highly susceptible to landslides under intense rainfalls. Failures of the slope during rainfall are closely related to the shear behavior of glacial tills ... Glacial tills are widely distributed in Tibet, China, and are highly susceptible to landslides under intense rainfalls. Failures of the slope during rainfall are closely related to the shear behavior of glacial tills at different moisture conditions. This study investigates the shear behavior and critical state of saturated and unsaturated glacial tills through a series of drained direct shear tests. The tests were conducted on two types of compacted glacial tills with different water contents and total normal stresses. A strain softening mode of failure is observed for all water content conditions accompanied by noticeable dilation. Dilatancy is found to decrease with increasing water content. Unsaturated samples showed increased rates of dilation as water content is decreased for all applied normal stresses a behavior which cannot be predicted well by classical stressdilatancy models. Furthermore, it was found that the Critical State Line(CSL), plotted on the(e-ln) plane, can be used to define the shear behavior of unsaturated glacial tills at different water contents.The CSL of saturated glacial tills run parallel to this line. The experimental results in this study are aimed to provide a basic understanding to the underlying failure mechanisms of glacial tills. 展开更多
关键词 GLACIAL TILL SHEAR behavior Water content DILATANCY Direct SHEAR test Critical state
润滑剂黏度对电工硅钢精密剪切加工影响 预览
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作者 阎秋生 汤彪 路家斌 《润滑与密封》 CAS CSCD 北大核心 2019年第8期1-7,22共8页
为研究润滑剂黏度对精密剪切加工断面质量的影响,在不同润滑剂黏度条件下以0. 5 mm厚的无取向电工硅钢为实验材料进行剪切加工实验,对比研究了不同润滑黏度时电工硅钢的剪切断面形貌、加工硬化以及剪切力。通过对比实验发现,电工硅钢精... 为研究润滑剂黏度对精密剪切加工断面质量的影响,在不同润滑剂黏度条件下以0. 5 mm厚的无取向电工硅钢为实验材料进行剪切加工实验,对比研究了不同润滑黏度时电工硅钢的剪切断面形貌、加工硬化以及剪切力。通过对比实验发现,电工硅钢精密剪切过程中润滑条件的改善,硅钢剪切断面质量得到提高,剪切带高度增加,塌角高度和毛刺高度减少,加工硬化减少;润滑剂黏度较小时,剪切力明显减小,相应的剪切区域的组织流动区域也明显变小,剪切带高度也明显变大。研究表明,润滑剂黏度的不同直接影响板材剪切过程中刀具与板材间的润滑状态,从而影响剪切力的大小和材料变形状态,进而影响剪切断面组织流动和剪切质量。 展开更多
关键词 电工硅钢 剪切 润滑 断面形貌 剪切力
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Erodibility study of sediment in a fast-flowing river 预览
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作者 Cheng He David Nguyen 《国际泥沙研究:英文版》 SCIE 2019年第2期144-154,共11页
Determination of sediment stability in the field is challenging because bed shear stress (BSS), a determining factor of sediment erosion, can’t easily be directly measured. To tackle this challenge and reliably asses... Determination of sediment stability in the field is challenging because bed shear stress (BSS), a determining factor of sediment erosion, can’t easily be directly measured. To tackle this challenge and reliably assess sediment erodibility in a fast flowing river, a standalone underwater camera system and a new insitu flume (ISF) were developed and applied in this study. The camera system was used to record sediment movement and the new ISF was used for measuring critical bottom shear stress (CBSS). The camera can be deployed alone in water to record videos or take pictures with light emitting diode (LED) lighting and flexible schedule settings. The ISF is based on the concept that the amount of force needed to erode the same particle under different flow conditions should be similar. Two high resolution Acoustic Doppler Current Profilers (ADCP) also were deployed in the field to collect velocity-depth profiles which are used by conventional methods to calculate BSS with the law of the wall. The sediment erodibility was then assessed based on the comparison between the obtained CBSS and BSS and then further verified with the recorded observations from the deployed camera. The results reveal that the widely used conventional method can produce large uncertainties and is not adequate to provide meaningful conclusion under these conditions. 展开更多
关键词 SEDIMENT ERODIBILITY BED SHEAR stress CRITICAL BED SHEAR stre
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闸式剪板机液压系统控制剪切角调整的设计 预览
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作者 窦高强 《锻压装备与制造技术》 2019年第1期32-34,共3页
重点介绍了闸式剪板机液压系统在调整剪切角变化时,在上腔增加插装阀来控制整个刀架变化,通过对整个系统动作及液压系统的性能的分析,指出系统解决了在剪切时变剪切角时整个刀架在变的现象,目的使系统设计更为合理,提高了整机的资源利... 重点介绍了闸式剪板机液压系统在调整剪切角变化时,在上腔增加插装阀来控制整个刀架变化,通过对整个系统动作及液压系统的性能的分析,指出系统解决了在剪切时变剪切角时整个刀架在变的现象,目的使系统设计更为合理,提高了整机的资源利用水平。 展开更多
关键词 剪板机 液压系统 剪切角变化
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吡丙醚系列悬浮剂自动化加工工艺研究 预览
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作者 苑志军 成庆勇 +2 位作者 郭聪 徐海燕 张芝平 《现代农药》 CAS 2019年第3期15-19,共5页
研究釡内剪切机形式、在线剪切、砂磨机锆珠填充率、砂磨机物料流量等参数对吡丙醚系列悬浮剂的粒径影响。结果表明,高剪切有助于快速降低粒径,在线剪切有助于改善粒径分布范围,达到均质的目的。研究吡丙醚系列悬浮剂的最佳锆珠填充率... 研究釡内剪切机形式、在线剪切、砂磨机锆珠填充率、砂磨机物料流量等参数对吡丙醚系列悬浮剂的粒径影响。结果表明,高剪切有助于快速降低粒径,在线剪切有助于改善粒径分布范围,达到均质的目的。研究吡丙醚系列悬浮剂的最佳锆珠填充率及砂磨物料流量,确定吡丙醚系列悬浮剂的最佳生产工艺条件。 展开更多
关键词 吡丙醚 粒径 剪切 砂磨
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Slope Stability Analyses of Outang Landslide Based on the Peak and Residual Shear Strength Behavior 预览
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作者 YANG Xiuhan VANAPALLI Sai 《工程科学与技术》 EI CAS CSCD 北大核心 2019年第4期55-68,共14页
Most of the natural and compacted fine-grained soil slopes that are in saturated or unsaturated condition undergo a large deformation prior to reaching failure conditions.Such slopes should be designed taking account ... Most of the natural and compacted fine-grained soil slopes that are in saturated or unsaturated condition undergo a large deformation prior to reaching failure conditions.Such slopes should be designed taking account of their strain-softening behavior using the residual shear strength (RSS) parameters.In this paper,the slope stability of a recently reactivated Outang landslide near the Three Gorges Dam in China is analyzed based on the RSS parameters of unsaturated soils.In addition,comparisons are provided in the FOS values of slope using both the peak shear strength (PSS) and RSS parameters.Firstly,a series of site investigations of the hydrologic and geologic conditions,ground surface displacements and cracks were described.The PSS and RSS behaviors of the sliding soils derived from a series of direct shear test results performed on saturated and unsaturated soil specimens are summarized.Secondly,a series of slope stability analysis were conducted considering the precipitation and Yangtze River water level variation within a representative period of 7 months,based on the PSS and the RSS properties.In this study,three different scenarios were considered,which include: i) considering only the precipitation with a constant water level;ii) considering only the decrease in water level without rainfall;iii) considering the combination of precipitation and decrease in water level.In each scenario,four steps were included to calculate the values of factor of safety (FOS) at different times.1) A steady-state seepage analysis was conducted with a constant total head at 525 m on the left boundary and 175 m on the slope surface below the Yangtze River water level.The initial pore water pressures were simulated in the slope under no precipitation and variation of water level.2) A specific boundary condition was applied on the slope surface to model the precipitation and Yangtze River water level variation.A transient seepage analysis was conducted to calculate pore water pressures at different times based on the initial po 展开更多
关键词 UNSATURATED soil LANDSLIDE REACTIVATION RESIDUAL shear strength SLOPE stability analysis
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多相土石复合介质推剪破坏电阻率响应特征试验研究 预览
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作者 李居铜 王日升 章传涛 《山东交通学院学报》 CAS 2019年第1期64-71,共8页
为获得土石复合介质剪切破坏过程中电阻率的变化规律,分别建立土石质量比为4:6、5:5、7:3的模型,并在不同含水条件下进行推剪试验,得出不同模型在推剪力作用下电阻率变化的响应特征及破坏时的电阻率。试验表明:浸水条件下各模型剪切时... 为获得土石复合介质剪切破坏过程中电阻率的变化规律,分别建立土石质量比为4:6、5:5、7:3的模型,并在不同含水条件下进行推剪试验,得出不同模型在推剪力作用下电阻率变化的响应特征及破坏时的电阻率。试验表明:浸水条件下各模型剪切时的电阻率均较正常条件下低,且随土石质量比的减少模型初始电阻率增大,破坏过程中电阻率稳定阶段响应特征更加显著。不同土石质量比复合介质模型在剪切过程中电阻率的响应特征说明,不同土石质量比复合介质的响应差异性巨大,变化规律可为利用电阻率无损检测土石边坡滑动等提供可靠的数据支撑。 展开更多
关键词 土石复合介质 剪切 位移 电阻率 响应特征
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A trigonometric series expansion method for the Orr-Sommerfeld equation 预览
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作者 Ying TAN Weidong SU 《应用数学和力学:英文版》 SCIE EI CSCD 2019年第6期877-888,共12页
A trigonometric series expansion method and two similar modified methods for the Orr-Sommerfeld equation are presented. These methods use the trigonometric series expansion with an auxiliary function added to the high... A trigonometric series expansion method and two similar modified methods for the Orr-Sommerfeld equation are presented. These methods use the trigonometric series expansion with an auxiliary function added to the highest order derivative of the unknown function and generate the lower order derivatives through successive integra- tions. The proposed methods are easy to implement because of the simplicity of the chosen basis functions. By solving the plane Poiseuille flow (PPF), plane Couette flow (PCF), and Blasius boundary layer flow with several homogeneous boundary conditions, it is shown that these methods yield results with the same accuracy as that given by the conventional Chebyshev collocation method but with better robustness, and that ob- tained by the finite difference method but with fewer modal number. 展开更多
关键词 Orr-Sommerfeld EQUATION SPECTRAL method trigonometric function PARALLEL SHEAR flow hydrodynamical stability EIGENVALUE PROBLEM
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Stress-dependent shear wave splitting and permeability in fractured porous rock 预览
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作者 Daisuke Katsuki Marte Gutierrez Abdulhadi Almrabat 《岩石力学与岩土工程学报:英文版》 CSCD 2019年第1期1-11,共11页
It is well known that shear wave propagates slower across than parallel to a fracture,and as a result,a travelling shear wave splits into two directions when it encounters a fracture.Shear wave splitting and permeabil... It is well known that shear wave propagates slower across than parallel to a fracture,and as a result,a travelling shear wave splits into two directions when it encounters a fracture.Shear wave splitting and permeability of porous rock core samples having single fracture were experimentally investigated using a high-pressure triaxial cell,which can measure seismic shear wave velocities in two directions mutually perpendicular to the sample axis in addition to the longitudinal compressive wave velocity.A single fracture was created in the samples using a modified Brazilian split test device,where the cylindrical sample edges were loaded on two diametrically opposite lines by sharp guillotines along the sample length.Based on tilt tests and fracture surface profilometry,the method of artificially induced tensile fracture in the sample was found to create repeatable fracture surfaces and morphologies.Seismic velocities of the fractured samples were determined under different levels of stress confinement and fracture shear displacement or mismatch.The effective confining stress was varied from 0.5 MPa to 55 MPa,while the fractures were mismatched by 0 mm,0.45 mm and 1 mm.The degree of matching of the fracture surfaces in the core samples was evaluated using the joint matching coefficient(JMC).Shear wave splitting,as measured by the difference in the magnitudes of shear wave velocities parallel(VS1)and perpendicular(VS2)to the fracture,is found to be insensitive to the degree of mismatching of the fracture joint surfaces at 2 MPa,and decreased and approached zero as the effective stress was increased.Simple models for the stress-and JMC-dependent shear wave splitting and fractured rock permeability were developed based on the experimental observations.The effects of the joint wall compressive strength(JCS),JMC and stress on the stress dependency of joint aperture were discussed in terms of hydro-mechanical response.Finally,a useful relationship between fractured rock permeability and shear wave splitting was found aft 展开更多
关键词 Fractured rock SANDSTONE STRESS DEPENDENCY Shear WAVE SPLITTING WAVE velocity PERMEABILITY Fracture stiffness Elastic modulus
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Buckling and post-buckling behavior of titanium alloy stiffened panels under shear load
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作者 Yuru SU Zhidong GUAN +3 位作者 Xin WANG Zengshan LI Jun GUO Yongjie HUANG 《中国航空学报:英文版》 SCIE EI CAS CSCD 2019年第3期619-626,共8页
Titanium alloy has been increasingly applied in aviation industry due to its superior performance. However, the titanium alloy structures are less studied. This work investigates the structural behavior of Ti6Al4V tit... Titanium alloy has been increasingly applied in aviation industry due to its superior performance. However, the titanium alloy structures are less studied. This work investigates the structural behavior of Ti6Al4V titanium alloy stiffened panels under in-plane shear load by experiments and numerical analysis. After the shear tests, the buckling instability, the post-buckling process and the failure mechanism of the specimen were obtained. The Finite Element(FE) models were established with the subsequent validation verification. A parametric analysis was implemented to study the influence of stringer thickness and stringer height on the behavior of the stiffened panels. The results show that after the initial local buckling on the skin, the buckling mode jumps several times with the increase of load. The stringers twist when the load reaches a certain level, and finally the structure damages due to the plastic deformation and the global buckling. The shear clip has little effect on the buckling and failure loads. Compared to the relatively large effect on the buckling load, the influence of the stringer thickness and stringer height on the failure load is neglectable.According to the parametric analysis, the stringer thickness influences the final buckling mode and failure mode, while the stringer height affects the buckling mode transformation. 展开更多
关键词 BUCKLING Finite Element Method(FEM) IN-PLANE shear loading Stiffened panel STRINGER HEIGHT STRINGER thickness Titanium alloys
Undrained shear strength evaluation for hydrate-bearing sediment overlying strata in the Shenhu area, northern South China Sea 预览
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作者 Yanlong Li Gaowei Hu +3 位作者 Nengyou Wu Changling Liu Qiang Chen Chen’an Li 《海洋学报:英文版》 SCIE CAS CSCD 2019年第3期114-123,共10页
The undrained shear strength of shallow strata is a critical parameter for safety design in deep-water operations.In situ piezocone penetration tests(CPTU) and laboratory experiments are performed at Site W18-19 in th... The undrained shear strength of shallow strata is a critical parameter for safety design in deep-water operations.In situ piezocone penetration tests(CPTU) and laboratory experiments are performed at Site W18-19 in the Shenhu area, northern South China Sea, where China’s first marine hydrate exploitation operation is due to be located. The validation of the undrained shear strength prediction model based on CPTU parameters. Different laboratory tests, including pocket penetrometer, torvane, miniature vane and unconsolidated undrained triaxial tests, are employed to solve empirical cone coefficients by statistical and mathematical methods. Finally, an optimized model is proposed to describe the longitudinal distribution of undrained shear strength in calcareous clay strata in the Shenhu area. Research results reveal that average empirical cone coefficients based on total cone resistance, effective resistance, and excess-pore pressure are 13.8, 4.2 and 14.4, respectively. The undrained shear strength prediction model shows a good fit with the laboratory results only within specific intervals based on their compaction degree and gas-bearing conditions. The optimized prediction model in piecewise function format can be used to describe the longitudinal distribution of the undrained shear strength for calcareous clay within all depth intervals from the mud-line to the upper boundary of hydrate-bearing sediments(HBS). The optimized prediction result indicates that the effective cone resistance model is suitable for very soft to firm calcareous clays,the excess-pore pressure model can depict the undrained shear strength for firm to very stiff but gas-free clays,while the total cone resistance model is advantageous for evaluating the undrained shear strength for very stiff and gassy clays. The optimized model in piecewise function format can considerably improve the adaptability of empirical models for calcareous clay in the Shenhu area. These results are significant for safety evaluations of proposed hydrate exploitat 展开更多
关键词 piezocone penetration TEST HYDRATE EXPLOITATION TEST UNDRAINED shear strength CALCAREOUS clay Shenhu area South China Sea
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Peristaltic Flow of Shear Thinning Fluid via Temperature-Dependent Viscosity and Thermal Conductivity
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作者 S.Noreen A.Malik M.M.Rashidi 《理论物理通讯:英文版》 SCIE CAS CSCD 2019年第4期367-376,共10页
In this paper Williamson ?uid is taken into account to study its peristaltic ?ow with heat effects. The study is carried out in a wave frame of reference for symmetric channel. Analysis of heat transfer is accomplishe... In this paper Williamson ?uid is taken into account to study its peristaltic ?ow with heat effects. The study is carried out in a wave frame of reference for symmetric channel. Analysis of heat transfer is accomplished by accounting the effects of non-constant thermal conductivity and viscosity and viscous dissipation. Modeling of fundamental equations is followed by the construction of closed form solutions for pressure gradient, stream function and temperature while assuming Reynold’s number to be very low and wavelength to be very long. Double perturbation technique is employed, considering Weissenberg number and variable ?uid property parameter to be very small. The effects of emerging parameters on pumping, trapping, axial pressure gradient, heat transfer coe?cient, pressure rise,velocity pro?le and temperature are analyzed through the graphical representation. A direct relation is observed between temperature and thermal conductivity whereas the indirect proportionality with viscosity. The heat transfer coe?cient is lower for a ?uid with variable thermal conductivity and variable viscosity as compared to the ?uid with constant thermal conductivity and constant viscosity. 展开更多
关键词 TEMPERATURE-DEPENDENT VISCOSITY TEMPERATURE-DEPENDENT thermal CONDUCTIVITY shear thinning?uid PERISTALSIS
Assessment of seismic amplifi cation factor of excavation with support system 预览
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作者 Hamidreza Tavakoli Saman Soleimani Kutanaei Seyed Hossein Hosseini 《地震工程与工程振动:英文版》 SCIE EI CSCD 2019年第3期555-566,共12页
Retaining walls have been used in many construction projects such as for road and inclined surfaces protection. The damage caused by an earthquake depends on the fundamental frequency, amplitude and the duration of th... Retaining walls have been used in many construction projects such as for road and inclined surfaces protection. The damage caused by an earthquake depends on the fundamental frequency, amplitude and the duration of the seismic motion. These parameters strongly depend on the seismic properties of the layers that are near the surface. In the study of retaining walls, in addition to the infl uence of soil, the infl uence of topography is also important. In the present study, site response analysis is performed by using fi nite element software PLAXIS to obtain the eff ect of various factors such as embedded length of the sheet pile, underground water table, length and angle of the nail, shear wave velocity of soil on site eff ect and dynamic response. Moreover, for better understanding of the eff ect of the above parameters, the stability analysis was performed by using shear reduction method. The results show that an increase in the embedded length of the sheet pile and the length of nailing causes an increase in the amplifi cation factor. Moreover, for shear-wave velocity in the range of 200- 600 m/s, the amplifi cation factor increases with increase of the shear-wave velocity due to the decrease of nonlinear behavior. 展开更多
关键词 amplifi CATION FACTOR safety FACTOR shear wave velocity NAILING sheet PILE
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Influences of soil moisture and salt content on loess shear strength in the Xining Basin, northeastern Qinghai-Tibet Plateau
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作者 FU Jiang-tao HU Xia-song +5 位作者 LI Xi-lai YU Dong-mei LIU Ya-bin YANG You-Qing QI Zhao-xin LI Shu-xia 《山地科学学报:英文版》 SCIE CSCD 2019年第5期1184-1197,共14页
Moisture and salt content of soil are the two predominant factors influencing its shear strength. This study aims to investigate the effects of these two factors on shear strength behavior of loess in the Xining Basin... Moisture and salt content of soil are the two predominant factors influencing its shear strength. This study aims to investigate the effects of these two factors on shear strength behavior of loess in the Xining Basin of Northeast Qinghai-Tibet Plateau, where such geological hazards as soil erosion, landslides collapse and debris flows are widespread due to the highly erodible loess. Salinized loess soil collected from the test site was desalinized through salt-leaching in the laboratory. The desalinized and oven-dried loess samples were also artificially moisturized and salinized in order to examine how soil salinity affects its shear strength at different moisture levels. Soil samples prepared in different ways(moisturizing, salt-leaching, and salinized) were measured to determine soil cohesion and internal friction angle. The results show that salt-leaching up to 18 rounds almost completely removed the salt content and considerably changed the physical components of loess, but the soil type remained unchanged. As salt content increases from 0.00% to 12.00%, both the cohesion and internal friction angle exhibit an initial decrease and then increase with salt content. As moisture content is 12.00%, the salt content threshold value for both cohesion and internal friction angle is identified as 3.00%. As the moisture content rises to 16.0% and 20.00%, the salt content threshold value for cohesion is still 6.00%, but 3.00% for internal friction angle. At these thresholds soil shear strength is the lowest, below which it is inversely related to soil salinity. Beyond the thresholds, however, the relationship is positive. Dissimilar to salinity, soil moisture content exerts an adverse effect on shear strength of loess. The findings of this study can provide a valuable guidance on stabilizing the engineering properties of salinized loess to prevent slope failures during heavy rainfall events. 展开更多
关键词 Salinized LOESS Desalinized LOESS Salt-leaching Shear strength indices Moisture CONTENT Salt CONTENT
Thixotropy of Systems with Shear Thinning and Plastic Flow Behavior 预览
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作者 Dimiter Hadjistamov 《材料科学与工程:中英文B版》 2019年第2期56-65,共10页
The definition of the thixotropy is a decrease in viscosity with time in shear and a subsequent recovery of viscosity after the shear deformation is removed.We used therefore start-up experiments with constant shear r... The definition of the thixotropy is a decrease in viscosity with time in shear and a subsequent recovery of viscosity after the shear deformation is removed.We used therefore start-up experiments with constant shear rates and can speak consequently of shear stress instead of viscosity.The shear stress increases sharply at the beginning of the stress growth experiment,passes an overshoot and begins to decrease up to the steady state shear stress.We can assume that a stress growth curve with an overshoot points out to thixotropic behavior.After the steady state shear stress is reached,the shear deformation is stopped,and the stress relaxation begins.It is to be expected that the shear stress will recover after the stress relaxation.Systems with shear thinning and plastic flow behavior were examined.The thixotropy is discussed in relation to the flow behavior.Stress growth experiments were performed with shear rates from the first Newtonian region and from the shear thinning region of the systems with shear thinning flow behavior.Stress start-up experiments were carrying out with shear rates from the first and second yield stress regions and from the transition section of a system with plastic flow behavior. 展开更多
关键词 THIXOTROPY rheopexy SYSTEMS with SHEAR THINNING FLOW BEHAVIOR SYSTEMS with plastic FLOW BEHAVIOR time related FLOW behaviour.
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Correlation Between Crystal Rotation and Redundant Shear Strain in Rolled Single Crystals: A Crystal Plasticity FE Analysis
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作者 Hui Wang Cheng Lu +3 位作者 Kiet Tieu Yu Liu Rui Wang Jintao Li 《金属学报:英文版》 SCIE EI CAS CSCD 2019年第4期452-460,共9页
The correlation between crystal rotation and redundant shear strain in rolled single crystals was investigated by using the crystal plasticity finite element(CPFE) model in this paper. The deformation in aluminium sin... The correlation between crystal rotation and redundant shear strain in rolled single crystals was investigated by using the crystal plasticity finite element(CPFE) model in this paper. The deformation in aluminium single crystals of four representative orientations(rotated-Cube, Goss, Copper, and Brass) after rolling and plain strain compression was simulated, and the predictions have been validated by the experimental observations. In the rotated-Cube and Goss, the redundant shear strain and crystal rotation were in the same pattern, alternating along the thickness, while the relation between them was not obvious for the Copper and Brass due to their asymmetrical distributions of activated slip systems. The relations between slip system activation, crystal rotation, and shear strain were investigated based on the CPFE model, and the correlation between shear strain and crystal rotation has been built. 展开更多
关键词 CRYSTAL PLASTICITY finite element Single CRYSTAL CRYSTAL ROTATION Shear strain Orientation stability
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