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Effects of gravel on the water absorption characteristics and hydraulic parameters of stony soil
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作者 MA Yan WANG Youqi +2 位作者 MA Chengfeng YUAN Cheng BAI Yiru 《Journal of Arid Land》 SCIE CSCD 2024年第7期895-909,共15页
The eastern foothills of the Helan Mountains in China are a typical mountainous region of soil and gravel,where gravel could affect the water movement process in the soil.This study focused on the effects of different... The eastern foothills of the Helan Mountains in China are a typical mountainous region of soil and gravel,where gravel could affect the water movement process in the soil.This study focused on the effects of different gravel contents on the water absorption characteristics and hydraulic parameters of stony soil.The stony soil samples were collected from the eastern foothills of the Helan Mountains in April 2023 and used as the experimental materials to conduct a one-dimensional horizontal soil column absorption experiment.Six experimental groups with gravel contents of 0%,10%,20%,30%,40%,and 50%were established to determine the saturated hydraulic conductivity(K_(s)),saturated water content(θ_(s)),initial water content(θ_(i)),and retention water content(θ_(r)),and explore the changes in the wetting front depth and cumulative absorption volume during the absorption experiment.The Philip model was used to fit the soil absorption process and determine the soil water absorption rate.Then the length of the characteristic wetting front depth,shape coefficient,empirical parameter,inverse intake suction and soil water suction were derived from the van Genuchten model.Finally,the hydraulic parameters mentioned above were used to fit the soil water characteristic curves,unsaturated hydraulic conductivity(K_(θ))and specific water capacity(C(h)).The results showed that the wetting front depth and cumulative absorption volume of each treatment gradually decreased with increasing gravel content.Compared with control check treatment with gravel content of 0%,soil water absorption rates in the treatments with gravel contents of 10%,20%,30%,40%,and 50%decreased by 11.47%,17.97%,25.24%,29.83%,and 42.45%,respectively.As the gravel content increased,inverse intake suction gradually increased,and shape coefficient,K_(s),θ_(s),andθ_(r)gradually decreased.For the same soil water content,soil water suction and K_(θ)gradually decreased with increasing gravel content.At the same soil water suction,C(h)decreased with increasing gravel content,and the water use efficiency worsened.Overall,the water holding capacity,hydraulic conductivity,and water use efficiency of stony soil in the eastern foothills of the Helan Mountains decreased with increasing gravel content.This study could provide data support for improving soil water use efficiency in the eastern foothills of the Helan Mountains and other similar rocky mountainous areas. 展开更多
关键词 stony soil gravel content water absorption characteristics hydraulic parameters one-dimensional horizontal soil column absorption experiment van Genuchten model eastern foothills of Helan Mountains
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Soil-water characteristic surface model of soil-rock mixture
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作者 WANG Kui HUI Ying +2 位作者 ZHOU Chuan LI Xue RONG Yao 《Journal of Mountain Science》 SCIE CSCD 2023年第9期2756-2768,共13页
The relationship between the water content or saturation of unsaturated soils and its matrix suction is commonly described by the soilwater characteristic curve(SWCC).Currently,study on the SWCC model is focused on fi... The relationship between the water content or saturation of unsaturated soils and its matrix suction is commonly described by the soilwater characteristic curve(SWCC).Currently,study on the SWCC model is focused on fine-grained soils like clay and silty soils,but the SWCC model for grinding soil-rock mixture(SRM)is less studied.Considering that the SRM is in a certain compaction state in the actual project,this study established a surface model with three variables of coupling compaction degree-substrate suction-moisture content based on the Cavalcante-Zornberg soil-water characteristic curve model.Then,the influence of each fitting parameter on the curve was analyzed.For the common SRM,the soil-water characteristic test was conducted.Moreover,the experimental measurements exhibit remarkable consistency with the mode surface.The analysis shows that the surface model intuitively describes the soil-water characteristics of grinding SRM,which can provide the SWCC of soils with bimodal pore characteristics under specific compaction degrees.Furthermore,it can reflect the influence of compaction degrees on the SWCC of rock-soil mass and has a certain prediction effect.The SWCC of SRM with various soil-rock ratios have a double-step shape.With the increase in compaction degree,the curves as a whole tend toward decreasing mass moisture content.The curve changes are mainly concentrated in the large pore section. 展开更多
关键词 Soil-rock mixture soil-water characteristic Surface model Compaction effect
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Water infiltration and soil-water characteristics of compacted loess under applied vertical stress
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作者 ZHANG Lin LI Tong-lu +2 位作者 LI Ji-heng LIANG Wei CHEN Cun-li 《Journal of Mountain Science》 SCIE CSCD 2023年第3期873-885,共13页
Additional stress formed by postconstruction buildings in loess-filling areas affects water infiltration in soil and causes soil deformation.To investigate this effect,under constant water head,vertical infiltration t... Additional stress formed by postconstruction buildings in loess-filling areas affects water infiltration in soil and causes soil deformation.To investigate this effect,under constant water head,vertical infiltration tests on compacted loess with two initial dry densities for different applied vertical stresses were developed using vertical stresscontrollable one-dimensional soil columns.The timehistory curves of vertical deformation,wetting front depth,cumulative infiltration depth,volumetric water content(VWC)and suction were measured,and the soil-water characteristic curves(SWCCs)were determined.The results showed that:(1)the infiltration ability of the soil column weakens with increasing applied vertical stress and initial dry density;(2)vertical deformation increases rapidly at first and then tends to be stable slowly at the consolidation and wetting-induced deformation stage,and is positively correlated with applied vertical stress and is negatively correlated with initial dry density.The stability time of wetting-induced deformation and the corresponding wetting front depth increase with the increase of applied vertical stress,while they decrease obviously when initial dry density increases;(3)the influence of applied vertical stress on soilwater characteristics in soil columns with various initial dry densities is related to the deformation depth of soil column.The VG(Van Genuchten)model is suitable for fitting the SWCCs at different monitoring positions.A normalized SWCC model introducing the applied vertical stress was proposed for each initial dry density using the mathematical relationship between the fitting parameters and the applied vertical stress. 展开更多
关键词 Additional stress LOESS Vertical deformation Wetting front Soil column soil-water characteristic curves
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Analysis of echo signal modulation characteristic parameters on aerial and space targets
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作者 Si Chen Hai-yang Zhang +3 位作者 Chang-ming Zhao Yu Fan Hong Chen Lin Wang 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2023年第10期146-154,共9页
Based on the scattering characteristic,the comparison of RCS(radar cross-section)at different positions of a target in the same direction of incidence can be obtained first by extruding or deleting part of the entity.... Based on the scattering characteristic,the comparison of RCS(radar cross-section)at different positions of a target in the same direction of incidence can be obtained first by extruding or deleting part of the entity.A simulation method of aerial&space targets echo characteristics(A&STEC)is proposed that is universal to aerial and space targets.We utilize a fixed-wing UAV(unmanned aerial vehicle)and typical missiles in simulation.The echo signal modulation characteristic parameters are calculated theoretically by the atmospheric attenuation model,the finite element method and a MUMPS solver.The verification simulations show that this method can analyze the influence of the target shape,incident direction,detection position and detection frequency on echo waveform,intensity and energy distribution.The results show that the profile of echo waveform can invert the general shape of the target.The relationship between time and intensity can determine whether the target is moving towards or away from the detector in addition.These conclusions can provide a reference for the ballistic missile target tracking and the defense against UVA intrusion in theory. 展开更多
关键词 Echo signal modulation characteristic parameters Simple targets The fixed-wing UVA Missiles Scattering characteristics
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Algorithms for automatic measurement of SIS-type hysteretic underdamped Josephson junction’s parameters by current-voltage characteristics
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作者 Aleksey G.Vostretsov Svetlana G.Filatova 《Journal of Electronic Science and Technology》 EI CSCD 2023年第4期60-74,共15页
Some electrical parameters of the SIS-type hysteretic underdamped Josephson junction(JJ)can be measured by its current-voltage characteristics(IVCs).Currents and voltages at JJ are commensurate with the intrinsic nois... Some electrical parameters of the SIS-type hysteretic underdamped Josephson junction(JJ)can be measured by its current-voltage characteristics(IVCs).Currents and voltages at JJ are commensurate with the intrinsic noise level of measuring instruments.This leads to the need for multiple measurements with subsequent statistical processing.In this paper,the digital algorithms are proposed for the automatic measurement of the JJ parameters by IVC.These algorithms make it possible to implement multiple measurements and check these JJ parameters in an automatic mode with the required accuracy.The complete sufficient statistics are used to minimize the root-mean-square error of parameter measurement.A sequence of current pulses with slow rising and falling edges is used to drive JJ,and synchronous current and voltage readings at JJ are used to realize measurement algorithms.The algorithm performance is estimated through computer simulations.The significant advantage of the proposed algorithms is the independence from current source noise and intrinsic noise of current and voltage meters,as well as the simple implementation in automatic digital measuring systems.The proposed algorithms can be used to control JJ parameters during mass production of superconducting integrated circuits,which will improve the production efficiency and product quality. 展开更多
关键词 Algorithm design and analysis Critical current Current-voltage characteristics(IVCs) Josephson junction(JJ) Measurement errors parameter estimation
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Study of Pyrolysis Characteristics and Kinetic Analysis of Shenmu Coal at a High Heating Rate Using TG-FTIR
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作者 An Xiaoxi Zhang Yanpeng +2 位作者 Shang Yanchao Tian Yuanyu Qiao Yingyun 《China Petroleum Processing & Petrochemical Technology》 SCIE CAS CSCD 2024年第1期47-55,共9页
Coal pyrolysis is a fundamental reaction in the thermal processing and utilization of coal.Investigating the behavior and kinetics of coal pyrolysis is crucial for optimizing,designing,and developing a composite riser... Coal pyrolysis is a fundamental reaction in the thermal processing and utilization of coal.Investigating the behavior and kinetics of coal pyrolysis is crucial for optimizing,designing,and developing a composite riser for the staged pyrolysis gasification process of pulverized coal.In this study,the non-isothermal pyrolysis behavior and kinetics of coal were examined at different heating rates(30,50,100,300,500,700,and 900℃/min)using thermogravimetry(TG)coupled with Fourier-transform infrared spectroscopy.Analysis of the TG/derivative TG(TG/DTG)curves indicated that coal pyrolysis mainly occurred between 300℃ and 700℃.Higher heating rates led to more volatiles being released from the coal,and a higher temperature was required to achieve rapid pyrolysis.Kinetic analysis showed that both the model-free methods(Friedman,Flynn-Wall-Ozawa,and Kissinger-Akahira-Sunose)and the model-based method(Coats-Redfern)effectively describe the coal pyrolysis process.The change in the Ea values between the two kinetic models was consistent throughout the pyrolysis process,and the most probable mechanism was the F2 model(secondary chemical reaction).In addition,the heating rate did not change the overall reaction order of the pyrolysis process;however,a higher heating rate resulted in a decrease in the Ea value during the initial pyrolysis stage. 展开更多
关键词 coal pyrolysis TG-FTIR characteristic parameters DYNAMICS
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Jet Characteristics and Optimization of a Cavitation Nozzle for Hydraulic Fracturing Applications
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作者 Yu Gao Zhenqiang Xu Kaixiang Shen 《Fluid Dynamics & Materials Processing》 EI 2024年第1期179-192,共14页
Hydraulic jetting is a form of fracturing that involves using a high-pressure jet of water to create fractures in the reservoir rock with a nozzle serving as the central component of the hydraulic sandblasting perfora... Hydraulic jetting is a form of fracturing that involves using a high-pressure jet of water to create fractures in the reservoir rock with a nozzle serving as the central component of the hydraulic sandblasting perforation tool.In this study,the flow behavior of the nozzle is simulated numerically in the framework of a SST k-ωturbulence model.The results show that the nozzle structure can significantly influence the jet performance and related cavitation effect.Through orthogonal experiments,the nozzle geometric parameters are optimized,and the following configuration is found accordingly:contraction angle 20°,contraction segment length 6 mm,cylindrical segment diameter 6 mm,cylindrical segment length 12 mm,spread segment length 10 mm,and spread angle 55°. 展开更多
关键词 Cavitation jet angle nozzle hydraulic characteristics nozzle parameters
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Distribution characteristics of dissolved organic carbon in annular wetland soil-water solutions through soil profiles in the Sanjiang Plain,Northeast China 被引量:15
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作者 XI Min LU Xian-guo +1 位作者 LI Yue KONG Fan-long 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2007年第9期1074-1078,共5页
Overwhelming evidence reveals that concentrations of dissolved organic carbon (DOC) have increased in streams which brings negative environmental impacts. DOC in stream flow is mainly originated from soil-water solu... Overwhelming evidence reveals that concentrations of dissolved organic carbon (DOC) have increased in streams which brings negative environmental impacts. DOC in stream flow is mainly originated from soil-water solutions of watershed. Wetlands prove to be the most sensitive areas as an important DOC reserve between terrestrial and fluvial biogeosystems. This reported study was focused on the distribution characteristics and the controlling factors of DOC in soil-water solutions of annular wetland, i.e., a dishing wetland and a forest wetland together, in the Sanjiang Plain, Northeast China. The results indicate that DOC concentrations in soilwater solutions decreased and then increased with increasing soil depth in the annular wetland. In the upper soil layers of 0-10 cm and 10-20 cm, DOC concentrations in soil-water solutions linearly increased from edge to center of the annular wetland (R^2 = 0.3122 and R^2 = 0.443). The distribution variations were intimately linked to DOC production and utilization and DOC transport processes in annular wetland soil-water solutions. The concentrations of total organic carbon (TOC), total carbon (TC) and Fe(II), DOC mobility and continuous vertical and lateral flow affectext the distribution variations of DOC in soil-water solutions. The correlation coefficients between DOC concentrations and TOC, TC and Fe(II) were 0.974, 0.813 and 0.753 respectively. These distribution characteristics suggested a systematic response of the distribution variations of DOC in annular wetland soil-water solutions to the geometry of closed depressions on a scale of small catchments. However, the DOC in soil pore water of the annular wetland may be the potential source of DOC to stream flow on watershed scale. These observations also implied the fragmentation of wetland landscape could bring the spatial-temporal variations of DOC distribution and exports, which would bring negative environmental impacts in watersheds of the Sanjiang Plain. 展开更多
关键词 dissolved organic carbon (DOC) distribution characteristics annular wetland soil-water solutions Sanjiang Plain
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Effect of temperature on soil-water characteristics and hysteresis of compacted Gaomiaozi bentonite 被引量:13
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作者 叶为民 万敏 +3 位作者 陈宝 陈永贵 崔玉军 王驹 《Journal of Central South University》 SCIE EI CAS 2009年第5期821-826,共6页
Laboratory tests under different constraint conditions were carried out to obtain the soil-water retention curves(SWRCs) of highly-compacted confined/unconfined Gaomiaozi(GMZ) bentonite at 20,40 and 80 ℃,respectively... Laboratory tests under different constraint conditions were carried out to obtain the soil-water retention curves(SWRCs) of highly-compacted confined/unconfined Gaomiaozi(GMZ) bentonite at 20,40 and 80 ℃,respectively. The effect of temperature on the soil-water characteristics of the highly-compacted GMZ bentonite was analyzed. The results show that the water retention capacity of the highly-compacted GMZ bentonite decreases as the temperature increases under unconfined and confined conditions. At a certain temperature,the constraint conditions have little influence on the water retention capacity of the compacted bentonite at high suction,but the water retention capacity of the confined specimen is lower than that of the unconfined specimen at low suction. Under unconfined conditions,the hysteretic behaviour of the compacted bentonite decreases with increasing temperature. At high suction(>4 MPa) ,the hysteretic behaviour of the unconfined bentonite tends to increase with the decrease of the suction. In summary,the hysteretic behaviour of the compacted bentonite is not significant. 展开更多
关键词 Gaomiaoz BENTONITE soil-water characteristic hysteretic behavior nuclear waste repository water retention capacity TEMPERATURE
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LAD PARAMETER ESTIMATION of SaS BASED on SAMPLE CHARACTERISTIC FUNCTION
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作者 陈高波 《科技信息》 2010年第25期I0028-I0028,I0027,共2页
Parameter estimation to alpha stable distribution is difficult for without a explicit probability density function. On the base of sample characteristic function,an iterative LAD parameter estimation algorithm for SaS... Parameter estimation to alpha stable distribution is difficult for without a explicit probability density function. On the base of sample characteristic function,an iterative LAD parameter estimation algorithm for SaS is discussed. The example illustrates that the algorithm is feasible and efficient. 展开更多
关键词 概率 密度函数 计算方法 迭代参数
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Influences affecting the soil-water characteristic curve 被引量:9
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作者 周建 俞建霖 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2005年第8期797-804,共8页
The soil-water characteristic curve (SWCC) is the primary partially saturated soil information as its behavior and properties can be derived from it. Although there have been many studies of unsaturated soils and the ... The soil-water characteristic curve (SWCC) is the primary partially saturated soil information as its behavior and properties can be derived from it. Although there have been many studies of unsaturated soils and the SWCC, there is still no combined constitutive model that can simulate soil characteristics accurately. In cases when hydraulic hysteresis is dominant (e.g. under cyclic loading) it is particularly important to use the SWCC. In the past decades, several mathematical expressions have been proposed to model the curve. There are various influences on the SWCC as a source of information, so the curves obtained from conventional tests often cannot be directly applied; and the mathematical expressions from one scenario cannot be used to simulate another situation. The effects of void ratio, initial water content, stress state and high suction were studied in this work revealing that water content and stress state are more important than the other effects; but that the influences tend to decrease when suction increases. The van Genuchten model was modified to simulate better the changes in the degree of saturation at low values of suction. Predictions were compared with experimental results to determine the simulation capability of the model. 展开更多
关键词 soil-water characteristic curve (SWCC) Unsaturated soil Mathematical expression
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Predicting the entire soil-water characteristic curve using measurements within low suction range 被引量:5
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作者 YE Yun-xue ZOU Wei-lie +1 位作者 HAN Zhong LIU Xiao-wen 《Journal of Mountain Science》 SCIE CSCD 2019年第5期1198-1214,共17页
The soil-water characteristic curve(SWCC) is widely used in the design and evaluation in the practice of geotechnical and geoenvironmental engineering such as the slope stability under the influence of environmental f... The soil-water characteristic curve(SWCC) is widely used in the design and evaluation in the practice of geotechnical and geoenvironmental engineering such as the slope stability under the influence of environmental factors. The SWCC has distinct features in the capillary and adsorption zones due to different physical mechanisms. Measurements of the SWCC are typically limited within the capillary zone(i.e., low suction range). It is cumbersome and time-consuming to measure the SWCC in the adsorption zone(i.e., high suction range). This study presents a simple method to predict the entire SWCC within both the capillary and adsorption zones, using measured data only from low suction range(e.g., from 0 to 500 kPa). Experimental studies were performed on a completely weathered granite residual soil to determine its entire SWCC from saturated to dry conditions. The resultant SWCC, along with the SWCC measurements of 14 soils reported in the literature, were used to validate the proposed method. The results indicate that the proposed method has good consistency with a wide array of measured data used in this study. The proposed method is easy to use as it only requires a simple parameter calibration for a commonly used SWCC model. It can be used to improve the reliability in the prediction of the SWCC over the entire suction range when measurements are limited within the low suction range. 展开更多
关键词 UNSATURATED SOILS soil-water characteristic CURVE CAPILLARY Adsorption Prediction
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Soil-water characteristics and shear strength in constant water content triaxial tests on Yunnan red clay 被引量:6
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作者 马少坤 黄茂松 +1 位作者 扈萍 杨超 《Journal of Central South University》 SCIE EI CAS 2013年第5期1412-1419,共8页
The shear strength parameters for geotechnical designs are obtained mainly from consolidated drained (CD) or consolidated undrained (CU) triaxial tests. However, during construction, the excess pore-air pressure g... The shear strength parameters for geotechnical designs are obtained mainly from consolidated drained (CD) or consolidated undrained (CU) triaxial tests. However, during construction, the excess pore-air pressure generally dissipates instantaneously while the excess pore-water pressure dissipates with time. This condition needs to be simulated in a constant water content (CW) triaxial test. The study on Yunnan red clay is carried out to investigate the soil-water characteristics and the shear strength characteristics under the constant water content condition. Osmotic technique is used to obtain the soil-water characteristic curve. A series of CW triaxial tests are conducted on statically compacted specimens. The experimental results show that the soil-water characteristic curve has a low air entry value of 7 kPa due to large pores in non-uniform pore size distribution, and a high residual value exceeding 10 MPa. In addition, the initial degree of saturation and net confining stress play an important role in affecting the shear characteristics under the constant water content condition. Finally, a new semi-empirical shear strength model in terms of degree of saturation is proposed and then applied to Yuunan red clay. Simulation result shows that the model is capable of capturing some key features of soils. The model can be used in whole engineering practice range, covering both unsaturmed and saturated soils. 展开更多
关键词 Yunnan red clay soil-water characteristic curve shear strength constant water triaxial test
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Infl uence of structural parameters on dynamic characteristics and wind-induced buffeting responses of a super-long-span cable-stayed bridge 被引量:5
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作者 Wang Hao Chen Chunchao +1 位作者 Xing Chenxi Li Aiqun 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2014年第3期389-399,共11页
A 3D finite element (FE) model for the Sutong cable-stayed bridge (SCB) is established based on ANSYS. The dynamic characteristics of the bridge are analyzed using a subspace iteration method. Based on recorded wi... A 3D finite element (FE) model for the Sutong cable-stayed bridge (SCB) is established based on ANSYS. The dynamic characteristics of the bridge are analyzed using a subspace iteration method. Based on recorded wind data, the measured spectra expression is presented using the nonlinear least-squares regression method. Turbulent winds at the bridge site are simulated based on the spectral representation method and the FFT technique. The influence of some key structural parameters and measures on the dynamic characteristics of the bridge are investigated. These parameters include dead load intensity, as well as vertical, lateral and torsional stiffness of the steel box girder. In addition, the influence of elastic stiffness of the connection device employed between the towers and the girder on the vibration mode of the steel box girder is investigated. The analysis shows that all of the vertical, lateral and torsional buffeting displacement responses reduce gradually as the dead load intensity increases. The dynamic characteristics and the structural buffeting displacement response of the SCB are only slightly affected by the vertical and torsional stiffness of the steel box girder, and the lateral and torsional buffeting displacement responses reduce gradually as the lateral stiffness increases. These results provide a reference for dynamic analysis and design of super-long-span cable-stayed bridges. 展开更多
关键词 cable-stayed bridge dynamic characteristics finite element (FE) method wind field simulation buffetingresponse parameter effects elastic connection device
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Prediction of loess soil-water characteristic curve by mercury intrusion porosimetry 被引量:4
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作者 LI Hua LI Tong-lu +1 位作者 LI Ping ZHANG Ya-guo 《Journal of Mountain Science》 SCIE CSCD 2020年第9期2203-2213,共11页
Mercury intrusion porosimetry(MIP)is a simple and fast way to obtain the pore distribution of soil and can be used to estimate the soil-water characteristic curve(SWCC).In previous studies,soil was assumed to be a per... Mercury intrusion porosimetry(MIP)is a simple and fast way to obtain the pore distribution of soil and can be used to estimate the soil-water characteristic curve(SWCC).In previous studies,soil was assumed to be a perfect wettability material,and the contact angle(CA)of the soil-water interface was taken as zero in the SWCC prediction method.However,the CA has proved to be much greater than zero even for hydrophilic soils according to some soil wettability experiments,and it has a significant effect on predicting the SWCC.In this research,a method for predicting the SWCC by MIP,which takes the CA as a fitting coefficient,is proposed.The pore size distribution curves are measured by MIP,and the SWCCs of two loess soils are measured by pressure plate and filter paper tests.When the CA is taken as70°and 50°for the wetting and drying process,respectively,the SWCCs predicted by the pore size distribution curves agree well with the measured SWCCs.The predicted suction range of the proposed method is 0-105 k Pa.The consistency of the results suggests that utilizing the MIP test to predict the SWCC with a proper CA is effective for loess. 展开更多
关键词 soil-water characteristic curve Mercury intrusion porosimetry Contact angle LOESS
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Synthetically quantitative evaluation function of characteristic parameters on CO_2 arc welding process 被引量:4
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作者 俞建荣 蒋力培 +2 位作者 史耀武 孙振国 王军波 《China Welding》 EI CAS 2001年第1期19-26,共8页
The statistical probability and their variation regularity of the measurable characteristic parameters in the CO 2 arc welding droplet short circuiting transfer process have been studied. The statistical analysis sh... The statistical probability and their variation regularity of the measurable characteristic parameters in the CO 2 arc welding droplet short circuiting transfer process have been studied. The statistical analysis shows that the sensitivity of each characteristic parameter with regard to the variation of the short circuiting transfer process is different. The sensitivity of 4 kinds among these characteristic parameters is more intense than that of the short circuiting transfer frequency. In order to take account of the synthetic influence of these characteristic parameters, by means of the characteristic parameters synthetic value, a quantitative evaluation function is built up to describe and evaluate the short circuiting transfer process of CO 2 arc welding in real time. The testing shows that the evaluation function can give a suitable synthetic valuation for the short circuiting transfer process with a variety of welding variables. 展开更多
关键词 CO 2 arc welding process characteristic parameters quantitative evaluation function
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Variation characteristics of aquifer parameters induced by groundwater source heat pump operation under variable flow 被引量:5
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作者 王松庆 张旭 《Journal of Central South University》 SCIE EI CAS 2011年第4期1272-1277,共6页
The variation characteristics of aquifer parameters,induced by groundwater source heat pump(GWSHP) operation under variable flow,were theoretically analyzed through a case study,in which the characteristics of buildin... The variation characteristics of aquifer parameters,induced by groundwater source heat pump(GWSHP) operation under variable flow,were theoretically analyzed through a case study,in which the characteristics of building air conditioning load were considered.The results,compared with the constant flow operation,indicate that the influence on the variations of porosity,hydraulic conductivity and confined water head is decreased by 48%,51% and 71%,respectively,under variable flow operation.The security of variable flow operation is superior to that of constant flow.It is also concluded that the climate region and function of the buildings are primary factors which affect the suitability of variable flow operation in GWSHP. 展开更多
关键词 groundwater source heat pump variation characteristic aquifer parameter variable flow
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Wave Characteristics and Extreme Parameters in the Bohai Sea 被引量:2
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作者 王智峰 吴克俭 +1 位作者 周良明 吴伦宇 《China Ocean Engineering》 SCIE EI 2012年第2期341-350,共10页
This paper is aimed at the whole Bohai Sea, as the complement and improvement of wave characteristics and extreme parameters. Wave fields were simulated in the Bohai Sea by using wave model SWAN from 1985 to 2004. The... This paper is aimed at the whole Bohai Sea, as the complement and improvement of wave characteristics and extreme parameters. Wave fields were simulated in the Bohai Sea by using wave model SWAN from 1985 to 2004. The input data based on the hindcast of high-resolution wind fields from RAMS and water level fields from POM, which have been tested and verified well. Comparisons of significant wave heights between simulation and station observations show a good agreement in general. By statistical analysis, the wave characteristics such as significant wave heights, dominant wave directions and their seasonal variations are discussed. In addition, main wave extreme parameters and directional extreme values particularly for 100-year return period are investigated. 展开更多
关键词 Bohai Sea wave fields statistical characteristics extreme parameters
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Field tests on mechanical characteristics and strength parameters of red-sandstone 被引量:3
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作者 蒋建清 杨果林 《Journal of Central South University》 SCIE EI CAS 2010年第2期381-387,共7页
Large-scale field shear tests on ten specimens of the red-sandstone embankment at a highway in Hunan,China,were performed to examine mechanical characteristics and parameters of red-sandstone.The curves of thrust-disp... Large-scale field shear tests on ten specimens of the red-sandstone embankment at a highway in Hunan,China,were performed to examine mechanical characteristics and parameters of red-sandstone.The curves of thrust-displacement,failure mode,and shear strength parameters for red-sandstone with different water contents,different compactions,and different grain size distributions were obtained from the tests.A practical procedure of in-situ test for red-sandstone embankment was proposed to normalize the test equipment and test steps.Based on three-dimensional thrust-sliding limit equilibrium method,the formulas for calculating strength parameters of red-sandstone considering three-dimensional sliding surface were inferred.The results show that red-sandstone has typical complete curves of stress-strain,strain softening,which are caused by the special structure of red-sandstone;water content and compaction are important factors for strength and failure mode of red-sandstone;The average value of cohesion and internal friction angle of the specimens calculated by three-dimensional technique are 21.56 kPa and 29.29°,respectively,and those by traditional two-dimensional method are 25.52 kPa and 33.76°,respectively. 展开更多
关键词 red-sandstone large-scale field test mechanical characteristic strength parameter
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Effect of working parameters on performance characteristics of hydrostatic turntable by using FSI-thermal model 被引量:3
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作者 HU Jun-ping LIU Cheng-pei 《Journal of Central South University》 SCIE EI CAS CSCD 2018年第11期2589-2600,共12页
Effects of working parameters on performance characteristics of hydrostatic turntable are researched by applying the fluid-structure-thermal coupled model.Fluid-structure interaction(FSI)technique and computational fl... Effects of working parameters on performance characteristics of hydrostatic turntable are researched by applying the fluid-structure-thermal coupled model.Fluid-structure interaction(FSI)technique and computational fluid dynamics(CFD)method are both employed by this new model,and thermal effects are also considered.Hydrostatic turntable systems with a series of oil supply pressures,various oil recess depth and several surface roughness parameters are studied.Performance parameters,such as turntable displacement,system flow rate,temperature rise of lubrication,stiffness and damping coefficients,are derived from different working parameters(rotational speed of turntable and exerted external load)of the hydrostatic turntable.Numerical results obtained from this FSI-thermal model are presented and discussed,and theoretical predictions are in good agreement with the experimental data.Therefore,this developed model is a very useful tool for studying hydrostatic turntables.The calculation results show that in order to obtain better performance,a rational selection of the design parameters is essential. 展开更多
关键词 hydrostatic turntable working parameters performance characteristics FSI-thermal coupled model
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