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Deadbands and the Dynamic Response and Performance of Large Water Transfer Canal System 被引量:2
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作者 DING Zhiliang WANG Changde TAN Guangming GUAN Guanghua 《Journal of Northeast Agricultural University(English Edition)》 CAS 2009年第2期58-65,共8页
An operating simulation mode for multireach canal system in series under gate regulating is established. The discharge feedforward plus water lever feedback PID controller was adopted. And the performance indicators a... An operating simulation mode for multireach canal system in series under gate regulating is established. The discharge feedforward plus water lever feedback PID controller was adopted. And the performance indicators are introduced to evaluate the control effects of canal operation. Influence on dynamic response process and dynamic performance as well as the control actions of canal system are studied according to the variation of the gate deadband and water level deadband. The results showed that the larger the gate deadband, the worse, the control effect of canal system over water level, and so done the stable process of gate discharge, yet the stable process of gate opening was getting better, while the upstream gate regulation of each canal pool was less at the time when canal stabilizes; the closer to downstream end of canal, the lager steady-state error of this canal pool was, and the lager influence of gate deadband on the steady-state error as well as response time of this canal pool was; the canal system can not acquire superiority in both the control performance and control actions when only the water level deadband was established. 展开更多
关键词 canal operation deadband PID controller performance indicator dynamic response dynamic performance
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Comparison of vibrations induced by excavation of deep-buried cavern and open pit with method of bench blasting 被引量:5
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作者 卢文波 李鹏 +2 位作者 陈明 周创兵 舒大强 《Journal of Central South University》 SCIE EI CAS 2011年第5期1709-1718,共10页
The measured data of vibrations induced by excavation of deep-buried cavern and open pit with method of bench blasting were analyzed by Fourier Transform and Wavelet Transform,and the characteristics of vibrations ind... The measured data of vibrations induced by excavation of deep-buried cavern and open pit with method of bench blasting were analyzed by Fourier Transform and Wavelet Transform,and the characteristics of vibrations induced under these two circumstances were studied.It is concluded that with the similar rock condition and drilling-blasting parameters,vibration induced by bench blasting in deep-buried cavern has a higher main frequency and more scattered energy distribution than that in open pit.The vibration induced by bench blasting in open pit is mainly originated from the blast load,while the vibration induced by bench blasting in deep-buried cavern is the superposition of vibrations induced by blast load and transient release of in-situ stress.The vibration induced by transient release of in-situ stress increases with the stress level. 展开更多
关键词 deep-buried cavem open pit blasting vibration power spectra time-energy density in-situ stress
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Factor analysis and numerical simulation of rock breaking efficiency of TBM deep rock mass based on orthogonal design 被引量:3
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作者 LI Xiao-jing ZHANG Hua-ken +1 位作者 BAI Yi-fan ZHANG Xiang-yang 《Journal of Central South University》 SCIE EI CAS CSCD 2022年第4期1345-1362,共18页
This study investigates the factors affecting the rock-breaking efficiency of the TBM disc cutter in deep rock excavation,including confining pressure,penetration,cutter spacing,and revolution speed.The finite element... This study investigates the factors affecting the rock-breaking efficiency of the TBM disc cutter in deep rock excavation,including confining pressure,penetration,cutter spacing,and revolution speed.The finite element method is employed to formulate a rock-breaking model of the rotary disc cutters and a numerical simulation is also implemented.The rock breaking effect,rock breaking volume,and rock breaking specific energy consumption under different combinations of the factors are investigated.An orthogonal test of four factors at four levels was constructed.Based on the test results and range analysis in the process of deep rock mass breaking,the order of sensitivity of each influencing factor with respect to the rock breaking specific energy for the disc cutter is cutter spacing>revolution speed>penetration>confining pressure.By constructing a numerical simulation comparison scheme,the orthogonal test results are analyzed and corroborated,and the rock breaking law and rock breaking efficiency under different influencing factors are derived.Finally,the sensitivity of different influencing factors on the rock-breaking efficiency is verified. 展开更多
关键词 deep rock mass TBM rock breaking rock breaking specific energy rock breaking efficiency
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Hydration properties and thermal analysis of cement-based materials containing limestone powder 被引量:2
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作者 ZHOU Wei LI Liang +1 位作者 LIU Shu-hua LIU Xing-hong 《Journal of Central South University》 SCIE EI CAS CSCD 2017年第12期2932-2939,共8页
The hydration and thermal properties of cement-based materials containing various proportions of limestone powder as a partial replacement for ordinary Portland cement, were investigated and reported. Both compressive... The hydration and thermal properties of cement-based materials containing various proportions of limestone powder as a partial replacement for ordinary Portland cement, were investigated and reported. Both compressive and flexural strengths of cement mortar with various contents of limestone powder were tested to study the influence of limestone powder on the strength development of resulting mixtures. The hydration heat and its rate of evolution were also tested, which clearly showed that the replacement percentage of limestone powder had significant effects on the total hydration heat but only a modest influence on the rate of heat evolution of cement-limestone binder. Importantly, the reduction coefficient of limestone powder on the hydration heat, needed for estimation of adiabatic temperature rise of cement-limestone binder, was found to be approximately 0.51. Fundamental thermal properties of these concrete mixtures containing limestone powder were also studied. Increasing the percentage of limestone powder resulted in a significant reduction in the adiabatic temperature rise but only a slight increase in other thermal properties such as thermal conductivity, thermal diffusivity and specific heat. In addition, thermal analysis using finite-element modelling indicated that inclusion of limestone powder did not significantly affect the rate of temperature rise nor the occurrence time of the highest temperature at early ages. 展开更多
关键词 LIMESTONE POWDER CEMENT MORTAR HYDRATION PROPERTIES thermal PROPERTIES
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Research on Controlled Volume Operation Method of Large-scale Water Transfer Canal
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作者 DING Zhiliang WANG Changde +1 位作者 XU Duo XIAO Hua 《Journal of Northeast Agricultural University(English Edition)》 CAS 2011年第3期47-59,共13页
The controlled volume method of operation is especially suitable for large-scale water delivery canal system with complex operation requirements. An operating simulation model based on the storage volume control metho... The controlled volume method of operation is especially suitable for large-scale water delivery canal system with complex operation requirements. An operating simulation model based on the storage volume control method for multi-reach canal system in series was established. In allusion to the deficiency of existing controlled volume algorithm, the improved controlled volume algorithm of the whole canal pools was proposed, and the simulation results indicated that the storage volume and water level of each canal pool could be accurately controlled after the improved algorithm had been adopted. However, for some typical discharge demand operating conditions, if the previously mentioned algorithm was adopted, then it certainly would cause some unnecessary gate adjustments, and consequently the disturbed canal pools would be increased. Therefore, the idea of controlled volume operation method of continuous canal pools was proposed, and corresponding algorithm was designed. Through simulating practical project, the results indicated that the new controlled volume algorithm proposed for typical operating conditions could comparatively and obviously reduce the number of regulated check gates and disturb canal pools for some typical discharge demand operating conditions, thus the control efficiency of canal system could be improved. 展开更多
关键词 canal operation controlled volume method of operation control algorithm SIMULATION
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Geotechnical stability analysis considering strain softening using micro-polar continuum finite element method 被引量:6
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作者 CHEN Xi WANG Dong-yong +2 位作者 TANG Jian-bin MA Wen-chen LIU Yong 《Journal of Central South University》 SCIE EI CAS CSCD 2021年第1期297-310,共14页
Geotechnical stability analyses based on classical continuum may lead to remarkable underestimations on geotechnical safety.To attain better estimations on geotechnical stability,the micro-polar continuum is employed ... Geotechnical stability analyses based on classical continuum may lead to remarkable underestimations on geotechnical safety.To attain better estimations on geotechnical stability,the micro-polar continuum is employed so that its internal characteristic length(lc)can be utilized to model the shear band width.Based on two soil slope examples,the role of internal characteristic length in modeling the shear band width of geomaterial is investigated by the second-order cone programming optimized micro-polar continuum finite element method.It is recognized that the underestimation on factor of safety(FOS)calculated from the classical continuum tends to be more pronounced with the increase of lc.When the micro-polar continuum is applied,the shear band dominated by lc is almost kept unaffected as long as the adopted meshes are fine enough,but it does not generally present a slip surface like in the cases from the classical continuum,indicating that the micro-polar continuum is capable of capturing the non-local geotechnical failure characteristic.Due to the coupling effects of lc and strain softening,softening behavior of geomaterial tends to be postponed.Additionally,the bearing capacity of a geotechnical system may be significantly underestimated,if the effects of lc are not modeled or considered in numerical analyses. 展开更多
关键词 slope stability strain localization non-local geotechnical failure micro-polar continuum internal characteristic length
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Stress-drop effect on brittleness evaluation of rock materials 被引量:3
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作者 SHI Gui-cai CHEN Guan +3 位作者 PAN Yu-tao YANG Xiao-li LIU Yong DAI Guo-zhong 《Journal of Central South University》 SCIE EI CAS CSCD 2019年第7期1807-1819,共13页
Uniaxial or triaxial compression test of cylindrical rock specimens using rock mechanics testing machine is a basic experimental method to study the strength and deformation characteristics of rock and the development... Uniaxial or triaxial compression test of cylindrical rock specimens using rock mechanics testing machine is a basic experimental method to study the strength and deformation characteristics of rock and the development process of rock fracture. Extensive literature review has been conducted on this issue;meanwhile, experimental and numerical studies have been conducted on the stress-drop effect on the brittleness of rock materials. A plastic flow factor of λ is proposed to describe the stress-drop effect. Evaluation methods of the factor λ corresponding to the four yield criteria of rock mass are proposed. Those four yield criteria are Tresca criterion, von-Mises criterion, Mohr-Coulomb criterion and Drucker-Prager criterion. For simplicity purposes, an engineering approximation approach has been proposed to evaluate the stress-drop with a non-zero strain increment. Numerical simulation results validated the effectiveness of the plastic flow factors λ as well as the engineering approximation approach. Based on the results in this study, finite element code can be programmed for brittle materials with stress-drop, which has the potential to be readily incorporated in finite element codes. 展开更多
关键词 rock material stress-drop effect plastic flow factor strength criteria
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Hydration mechanism of low quality fly ash in cement-based materials 被引量:11
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作者 刘数华 孔亚宁 王露 《Journal of Central South University》 SCIE EI CAS 2014年第11期4360-4367,共8页
The hydration mechanism of low quality fly ash in cement-based materials was investigated. The hydration heat of the composite cementitious materials was determined by isothermal calorimetry, and the hydration product... The hydration mechanism of low quality fly ash in cement-based materials was investigated. The hydration heat of the composite cementitious materials was determined by isothermal calorimetry, and the hydration products, quantity, pore structure and morphology were measured by X-ray diffraction(XRD), thermalgravity-differential thermal analysis(TG-DTA), mercury intrusion porosimetry(MIP) and scanning electron microscopy(SEM), respectively. The results indicate that grinding could not only improve the physical properties of the low quality fly ash on particle effect, but also improve hydration properties of the cementitious system from various aspects compared with raw low quality fly ash(RLFA). At the early stage of hydration, the low quanlity fly ash acts as almost inert material; but then at the later stage, high chemical activity, especially for ground low quality fly ash(GLFA), could be observed. It can accelerate the formation of hydration products containing more chemical bonded water, resulting in higher degree of cement hydration, thus denser microstructure and more reasonable pore size distribution, but the hydration heat in total is reduced. It can also delay the induction period, but the accelerating period is shortened and there is little influence on the second exothermic peak. 展开更多
关键词 low quality fly ash cement-based materials hydration products pore structure
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Numerical simulation of cavitation around a Clark-Y hydrofoil with different LES models in OpenFOAM 被引量:1
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作者 ZHU Ziming QIAN Zhongdong +1 位作者 GUO Zhiwei YANG Bing 《排灌机械工程学报》 EI CSCD 北大核心 2018年第4期277-282,共6页
A finite volume,multiphase solver in the framework of OpenFOAM was used to calculate the flow field of the cavitating flow over the Clark-Y hydrofoil. This solver used Transport Based Equation Model(TEM) to solve the ... A finite volume,multiphase solver in the framework of OpenFOAM was used to calculate the flow field of the cavitating flow over the Clark-Y hydrofoil. This solver used Transport Based Equation Model(TEM) to solve the liquid volume fraction,and utilized volume of fluid(VOF) technique to predict the interface between liquid and vapor phases. The simulation was designed to study the cavitation shedding and different fluid characteristics in the cloud cavitation regime when adopting two different Large Eddy Simulation(LES) models,namely,one equation eddy viscosity(one EqEddy) model and Smagorinsky model. It is shown that these two models can be used to study the cavitation shedding dynamics and predict the velocity profiles. 展开更多
关键词 HYDROFOIL CAVITATION OPENFOAM Large EDDY Simulation
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Parametric modeling on spatial effect of excavation-damaged zone of underground cavern 被引量:1
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作者 刘会波 肖明 陈俊涛 《Journal of Central South University》 SCIE EI CAS 2013年第4期1085-1093,共9页
Regarding excavation-damaged zone (EDZ) around underground opening as non-homogeneous rockmass with spatial deterioration effect on stuffiness and strength, a parametric model of EDZ using radius-displacement-depend... Regarding excavation-damaged zone (EDZ) around underground opening as non-homogeneous rockmass with spatial deterioration effect on stuffiness and strength, a parametric model of EDZ using radius-displacement-dependent deformation modulus (RDDM) was proposed. Considering the nonlinearity characteristic of deformation and locality otherness of surrounding rock, deterioration parameter field of deformation modulus of rockmass around opening was quantitatively calculated through a given function. Applicability for multi-cavern condition and parameter sensibility of the model was analyzed by numerical experiments using synthetic data. Furthermore, the model was applied to identify EDZ of underground caverns of Pubugou hydropower station by calculating deterioration parameter field. Based on the parametric analysis of spatial effect and geological investigation, it is recognized that large radial deformation of deep fractured rock at the spandrel position and insufficient supporting bolts mainly result in great deformation pressure to act on the shotcrete and cause partial crack and spalling. It is shown that deterioration parameter field along the longitudinal axis of main powerhouse is evidently non-homogeneous in space and distributes exponentially along the radius from the opening. The model provides a simple and convenient way to identify the EDZ in the working state for rapid construction feedback analysis and support optimization of underground cavem from quantitative point of view and also aids in interpreting monitoring displacements and estimating support requirements. 展开更多
关键词 underground cavern excavation-damaged zone spatial effect parametric modeling deformation modulus
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Coupling model for assessing anti-seepage behavior of curtain under dam foundation 被引量:1
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作者 彭鹏 单治钢 董育烦 《Journal of Central South University》 SCIE EI CAS 2012年第7期2016-2021,共6页
The seepage under a dam foundation is mainly controlled by the performance of the curtain.Its anti-seepage behavior may be weakened by the long term physic-chemical actions from groundwater.According to seepage hydrau... The seepage under a dam foundation is mainly controlled by the performance of the curtain.Its anti-seepage behavior may be weakened by the long term physic-chemical actions from groundwater.According to seepage hydraulics and geochemistry theory,a coupling model for assessing the behavior of the curtain under a dam foundation is set up,which consists of seepage module,solute transport module,geochemistry module and curtain erosion module,solved by FEM.A case study was carried out.The result shows that the curtain efficiency is weakened all the time.Aqueous calcium from the curtain is always in dissolution during the stress period for simulation,which leads to the increasing amount in groundwater reaching 846.35-865.312 g/m3.Within the domain,reaction extent differs in different parts of the curtain.The dissolution of Ca(OH)2 accounts to 877.884 g/m3 near the bottom and is much higher than that of the other parts.The erosion is much more serious near the bottom of the curtain than the other parts,which is the same to the upstream and downstream.Calcium dissolution is mainly controlled by hydraulic condition and dispersion,and it varies in a non-linear way within the domain. 展开更多
关键词 CURTAIN dam foundation SEEPAGE calcium ion leaching coupling model
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Effect of wall jet on the bubble dynamics near arigid wall
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作者 LU Jie QIAN Zhongdong +2 位作者 GUO Zhiwei WANG Chihang SU Jiahui 《排灌机械工程学报》 EI CSCD 北大核心 2017年第6期467-471,共5页
The bubble dynamic near a rigid wall with a wall jet was investigated by codynamics(CFD)method with the volume of fluid(VOF)model,which had been validated by vious experimental data.The effects of different velocities... The bubble dynamic near a rigid wall with a wall jet was investigated by codynamics(CFD)method with the volume of fluid(VOF)model,which had been validated by vious experimental data.The effects of different velocities of the wall jet and ditances on the bubble dynamics were studied.The results show that the bubble is squjet due to more force added on the bubble.When the velocity of the wall jet increa,the wall anthe pressure along the wall at collapse time increase because of the extra push indAs the stand-off distance increases,the pressure along the wall first increases then decrethe distance from the bubble to the wall increases. 展开更多
关键词 bubble dynamic wall jet volume of fluid computational fluid dynamics(CFD)
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天然气水合物稳定带内流体压裂计算的程序耦合方法 被引量:2
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作者 刘金龙 王淑红 +5 位作者 Asiri Obeysekara XIANG Jiansheng Pablo Salinas Christopher Pain Jonny Rutqvist 颜文 《热带海洋学报》 CAS CSCD 北大核心 2020年第1期94-105,共12页
海洋天然气水合物稳定带气烟囱结构中存在被水合物充填的裂隙,表明在自然条件下沉积物中曾发生过流体压裂以及相关的流体流动和水合物形成。在水合物稳定带内实施人为的流体压裂工程,并联合其他方法(如降压或注热)进行水合物开采,有望... 海洋天然气水合物稳定带气烟囱结构中存在被水合物充填的裂隙,表明在自然条件下沉积物中曾发生过流体压裂以及相关的流体流动和水合物形成。在水合物稳定带内实施人为的流体压裂工程,并联合其他方法(如降压或注热)进行水合物开采,有望提高开采效率。水合物稳定带内,无论是自然条件下发生的流体压裂过程,还是人为实施的流体压裂工程,都存在水合物反应和沉积物裂隙变形之间的耦合响应。当前,已有不少数值程序对水合物反应与沉积物弹塑性变形的耦合过程进行了定量研究,但尚没有数值程序能够计算水合物反应和离散裂隙变形之间的耦合过程。文章将TOUGH+Hydrate程序、IC-FERST和Solidity两者的耦合程序进行了进一步耦合,为水合物稳定带内的流体压裂计算提供了一种耦合计算方法,同时通过一个算例初步验证了该耦合计算方法的可行性。验证结果表明,该耦合计算方法经进一步改进后有望应用于定量研究水合物稳定带内的裂隙变形和水合物反应过程。 展开更多
关键词 天然气水合物 流体压裂 计算程序 程序耦合
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面板堆石坝变形监测研究(英文) 被引量:1
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作者 Anna Szostak-Chrzanowski DENG Nian-wu +1 位作者 LI Min Michel Massiera 《岩土工程学报》 EI CAS CSCD 北大核心 2008年第11期1651-1656,共6页
面板堆石坝的安全依赖于良好的设计、施工和在大坝施工及运行期的实时监测,土工监测技术和测绘技术可以用来监测大坝位移,并对大坝的非正常变形提供预警。面板堆石坝一般在施工期和蓄水期会发生较大变形:在施工期,堆石体和上游面板会因... 面板堆石坝的安全依赖于良好的设计、施工和在大坝施工及运行期的实时监测,土工监测技术和测绘技术可以用来监测大坝位移,并对大坝的非正常变形提供预警。面板堆石坝一般在施工期和蓄水期会发生较大变形:在施工期,堆石体和上游面板会因为自重而相互积压发生变形;在蓄水期,堆石体和上游面板会在水压力的作用下发生变形。为了保证面板的整体性和大坝安全,特别要防止面板的变形超过其最大允许变形。由于对筑坝材料参数的不完全可知性和计算理论的不完善,必须对大坝及其周边变形进行严密监测以预防大坝发生较大变形。应用有限元方法对中国某面板堆石坝位移变化进行研究。 展开更多
关键词 面板堆石坝 位移分析 有限元 安全监测
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