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Design method of high prestressed support for shallow-buried large-span caverns
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作者 JIANG Bei WEI Hua-yong +3 位作者 WANG Qi WANG Ming-zi YIN Chen ZHANG Yan-bo 《Journal of Central South University》 2025年第3期1099-1116,共18页
The surrounding rock is prone to large-scale loosening and failure after the excavation of shallow large-span caverns because of the thin overlying strata and large cross-section span.The rational design of bolt suppo... The surrounding rock is prone to large-scale loosening and failure after the excavation of shallow large-span caverns because of the thin overlying strata and large cross-section span.The rational design of bolt support is very important to the safety control of surrounding rock as a common support means.The control mechanism and design method of bolt support for shallow-buried large-span caverns is carried out.The calculation method of bolt prestress and length based on arched failure and collapsed failure mode is established.The influence mechanism of different influencing factors on the bolt prestress and length is clarified.At the same time,the constant resistance energy-absorbing bolt with high strength and high toughness is developed,and the comparative test of mechanical properties is carried out.On this basis,the design method of high prestressed bolt support for shallow-buried large-span caverns is put forward,and the field test is carried out in Qingdao metro station in China.The monitoring results show that the maximum roof settlement is 6.8 mm after the new design method is adopted,and the effective control of the shallow-buried large-span caverns is realized.The research results can provide theoretical and technical support for the safety control of shallow-buried large-span caverns. 展开更多
关键词 Hoek-Brown strength criterion shallow-buried large-span caverns limit analysis upper bound method high prestress bolt support design method
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Influence of joint spacing and rock characteristics on the toppling stability of cut rock slope through a simplified limit equilibrium method
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作者 ZHANG Xue-peng JIANG Yu-jing +6 位作者 DU Yan WANG Ke-peng CAI Yue WANG Xing-da SU Hang GOLSANAMI Naser LIU Bao-guo 《Journal of Central South University》 SCIE EI CAS CSCD 2024年第8期2694-2702,共9页
Toppling failure of rock mass/soil slope is an important geological and environmental problem.Clarifying its failure mechanism under different conditions has great significance in engineering.The toppling failure of a... Toppling failure of rock mass/soil slope is an important geological and environmental problem.Clarifying its failure mechanism under different conditions has great significance in engineering.The toppling failure of a cutting slope occurred in a hydropower station in Kyushu,Japan illustrates that the joint characteristic played a significant role in the occurrence of rock slope tipping failure.Thus,in order to consider the mechanical properties of jointed rock mass and the influence of geometric conditions,a simplified analytical approach based on the limit equilibrium method for modeling the flexural toppling of cut rock slopes is proposed to consider the influence of the mechanical properties and geometry condition of jointed rock mass.The theoretical solution is compared with the numerical solution taking Kyushu Hydropower Station in Japan as one case,and it is found that the theoretical solution obtained by the simplified analysis method is consistent with the numerical analytical solution,thus verifying the accuracy of the simplified method.Meanwhile,the Goodman-Bray approach conventionally used in engineering practice is improved according to the analytical results.The results show that the allowable slope angle may be obtained by the improved Goodman-Bray approach considering the joint spacing,the joint frictional angle and the tensile strength of rock mass together. 展开更多
关键词 slope stability flexural toppling rock slope simplified limit equilibrium method
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Data-driven methods for predicting the representative temperature of bridge cable based on limited measured data
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作者 WANG Fen DAI Gong-lian +2 位作者 HE Chang-lin GE Hao RAO Hui-ming 《Journal of Central South University》 SCIE EI CAS CSCD 2024年第9期3168-3186,共19页
Cable-stayed bridges have been widely used in high-speed railway infrastructure.The accurate determination of cable’s representative temperatures is vital during the intricate processes of design,construction,and mai... Cable-stayed bridges have been widely used in high-speed railway infrastructure.The accurate determination of cable’s representative temperatures is vital during the intricate processes of design,construction,and maintenance of cable-stayed bridges.However,the representative temperatures of stayed cables are not specified in the existing design codes.To address this issue,this study investigates the distribution of the cable temperature and determinates its representative temperature.First,an experimental investigation,spanning over a period of one year,was carried out near the bridge site to obtain the temperature data.According to the statistical analysis of the measured data,it reveals that the temperature distribution is generally uniform along the cable cross-section without significant temperature gradient.Then,based on the limited data,the Monte Carlo,the gradient boosted regression trees(GBRT),and univariate linear regression(ULR)methods are employed to predict the cable’s representative temperature throughout the service life.These methods effectively overcome the limitations of insufficient monitoring data and accurately predict the representative temperature of the cables.However,each method has its own advantages and limitations in terms of applicability and accuracy.A comprehensive evaluation of the performance of these methods is conducted,and practical recommendations are provided for their application.The proposed methods and representative temperatures provide a good basis for the operation and maintenance of in-service long-span cable-stayed bridges. 展开更多
关键词 cable-stayed bridges representative temperature gradient boosted regression trees(GBRT)method field test limited measured data
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Hybrid LEAP modeling method for long-term energy demand forecasting of regions with limited statistical data 被引量:4
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作者 CHEN Rui RAO Zheng-hua LIAO Sheng-ming 《Journal of Central South University》 SCIE EI CAS CSCD 2019年第8期2136-2148,共13页
An accurate long-term energy demand forecasting is essential for energy planning and policy making. However, due to the immature energy data collecting and statistical methods, the available data are usually limited i... An accurate long-term energy demand forecasting is essential for energy planning and policy making. However, due to the immature energy data collecting and statistical methods, the available data are usually limited in many regions. In this paper, on the basis of comprehensive literature review, we proposed a hybrid model based on the long-range alternative energy planning (LEAP) model to improve the accuracy of energy demand forecasting in these regions. By taking Hunan province, China as a typical case, the proposed hybrid model was applied to estimating the possible future energy demand and energy-saving potentials in different sectors. The structure of LEAP model was estimated by Sankey energy flow, and Leslie matrix and autoregressive integrated moving average (ARIMA) models were used to predict the population, industrial structure and transportation turnover, respectively. Monte-Carlo method was employed to evaluate the uncertainty of forecasted results. The results showed that the hybrid model combined with scenario analysis provided a relatively accurate forecast for the long-term energy demand in regions with limited statistical data, and the average standard error of probabilistic distribution in 2030 energy demand was as low as 0.15. The prediction results could provide supportive references to identify energy-saving potentials and energy development pathways. 展开更多
关键词 energy demand forecasting with limited data hybrid LEAP model ARIMA model Leslie matrix Monte-Carlo method
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Predication of Plastic Flow Characteristics in Ferrite/Pearlite Steel Using a Fern Unit Cell Method
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作者 Hong Li Jingtao Han Jing Liu Lv Zhang 《上海交通大学学报》 EI CAS CSCD 北大核心 2004年第z2期61-66,共6页
The flow stress of ferrite/pearlite steel under uni-axial tension was simulated with finite element method (FEM) by applying commercial software MARC/MENTAT. Flow stress curves of ferrite/pearlite steels were calculat... The flow stress of ferrite/pearlite steel under uni-axial tension was simulated with finite element method (FEM) by applying commercial software MARC/MENTAT. Flow stress curves of ferrite/pearlite steels were calculated based on unit cell model. The effects of volume fraction, distribution and the aspect ratio of pearlite on tensile properties have been investigated. 展开更多
关键词 ferrite/pearlite STEEL unit cell flow CURVE FINITE element method simulation
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Research on Test Data Distribution of Strapdown Inertial Measurement Unit Based on Bayesian Method 被引量:1
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作者 徐军辉 汪立新 钱培贤 《Defence Technology(防务技术)》 SCIE EI CAS 2008年第3期214-217,共4页
Aiming at that the successive test data set of the strapdown inertial measurement unit is always small,a Bayesian method is used to study its statistical characteristics.Its prior and posterior distributions are set u... Aiming at that the successive test data set of the strapdown inertial measurement unit is always small,a Bayesian method is used to study its statistical characteristics.Its prior and posterior distributions are set up by the method and the pretest,sample and population information.Some statistical inferences can be made based on the posterior distribution.It can reduce the statistical analysis error in the case of small sample set. 展开更多
关键词 战术导弹 数学统计学 惯性测量 技术性能
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An improved limit equilibrium method for rock slope stability analysis under stress-based calculation mode for slip surface
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作者 DENG Dong-ping ZHANG Dian +1 位作者 PENG Yi-hang CHEN Hao-yu 《Journal of Central South University》 2025年第1期262-287,共26页
This study proposes an alternative calculation mode for stresses on the slip surface(SS).The calculation of the normal stress(NS)on the SS involves examining its composition and expanding its unknown using the Taylor ... This study proposes an alternative calculation mode for stresses on the slip surface(SS).The calculation of the normal stress(NS)on the SS involves examining its composition and expanding its unknown using the Taylor series.This expansion enables the reasonable construction of a function describing the NS on the SS.Additionally,by directly incorporating the nonlinear Generalized Hoke-Brown(GHB)strength criterion and utilizing the slope factor of safety(FOS)definition,a function of the shear stress on the SS is derived.This function considers the mutual feedback mechanism between the NS and strength parameters of the SS.The stress constraints conditions are then introduced at both ends of the SS based on the spatial stress relation of one point.Determining the slope FOS and stress solution for the SS involves considering the mechanical equilibrium conditions and the stress constraint conditions satisfied by the sliding body.The proposed approach successfully simulates the tension-shear stress zone near the slope top and provides an intuitive description of the concentration effect of compression-shear stress of the SS near the slope toe.Furthermore,compared to other methods,the present method demonstrates superior processing capabilities for the embedded nonlinear GHB strength criterion. 展开更多
关键词 stability of rock slope nonlinear GHB strength criterion limit equilibrium method stress function on slip surface stress constraint conditions at both ends of slip surface
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Formability improvement and blank shape definition for deep drawing of cylindrical cup with complex curve profile from SPCC sheets using FEM 被引量:3
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作者 Duc-Toan Nguyen Duy-Khoe Dinh +2 位作者 Hong-Minh Thi Nguyen Tien-Long Banh Young-Suk Kim 《Journal of Central South University》 SCIE EI CAS 2014年第1期27-34,共8页
In the current work, to predict and improve the formability of deep drawing process for steel plate cold rolled commercial grade (SPCC) sheets, three parameters including the blanking force, the die and punch comer ... In the current work, to predict and improve the formability of deep drawing process for steel plate cold rolled commercial grade (SPCC) sheets, three parameters including the blanking force, the die and punch comer radius were considered. The experimental plan according to Taguchi's orthogonal array was coupled with the finite element method (FEM) simulations. Firstly, the data from the test of stress-strain and forming limit curves were used as input into ABAQUS/Explicit finite element code to predict the failure occurrence of deep drawing process. The three parameters were then validated to establish their effects on the press formability. The optimum case found via simulation was finally confirmed through an experiment. In order to obtain the complex curve profile of cup shape after deep drawing, the anisotropic behavior of earring phenomenon was modeled and implemented into FEM. After such phenomenon was correctly predicted, an error metric compared with design curve was then measured. 展开更多
关键词 finite element method SPCC DEEP-DRAWING forming limit diagram criterion Taguchi's method earring prediction
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Optimization principle of combined surface and underground mining and its applications 被引量:3
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作者 陈建宏 古德生 李建雄 《Journal of Central South University of Technology》 2003年第3期222-225,共4页
The pit limit optimization is discussed, which is one of the most important problems in the combined min-ing method, on the basis of the economic model of ore-blocks. A new principle of the limit optimization is put f... The pit limit optimization is discussed, which is one of the most important problems in the combined min-ing method, on the basis of the economic model of ore-blocks. A new principle of the limit optimization is put for-ward through analyzing the limitations of moving cone method under such conditions. With a view to recovering asmuch mineral resource as possible and making the maximum profit from the whole deposit, the new principle is tomaximize the sum of gain from both open-pit and underground mining. The mathematical models along the horizon-tal and vertical directions and modules for software package (DM&MCAD) have been developed and tested inTonglushan Copper Mine. It has been proved to be rather effective in the mining practice. 展开更多
关键词 surface MINING UNDERGROUND MINING combined MINING method OPTIMIZATION MODEL open PIT limit block economic MODEL
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Optimal trajectory and heat load analysis of different shape lifting reentry vehicles for medium range application 被引量:7
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作者 S.Tauqeer ul Islam RIZVI Lin-shu HE Da-jun XU 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2015年第4期350-361,共12页
The objective of the paper is to compute the optimal burn-out conditions and control requirements that would result in maximum down-range/cross-range performance of a waverider type hypersonic boost-glide(HBG) vehicle... The objective of the paper is to compute the optimal burn-out conditions and control requirements that would result in maximum down-range/cross-range performance of a waverider type hypersonic boost-glide(HBG) vehicle within the medium and intermediate ranges,and compare its performance with the performances of wing-body and lifting-body vehicles vis-a-vis the g-load and the integrated heat load experienced by vehicles for the medium-sized launch vehicle under study.Trajectory optimization studies were carried out by considering the heat rate and dynamic pressure constraints.The trajectory optimization problem is modeled as a nonlinear,multiphase,constraint optimal control problem and is solved using a hp-adaptive pseudospectral method.Detail modeling aspects of mass,aerodynamics and aerothermodynamics for the launch and glide vehicles have been discussed.It was found that the optimal burn-out angles for waverider and wing-body configurations are approximately 5° and 14.8°,respectively,for maximum down-range performance under the constraint heat rate environment.The down-range and cross-range performance of HBG waverider configuration is nearly 1.3 and 2 times that of wing-body configuration respectively.The integrated heat load experienced by the HBG waverider was found to be approximately an order of magnitude higher than that of a lifting-body configuration and 5 times that of a wing-body configuration.The footprints and corresponding heat loads and control requirements for the three types of glide vehicles are discussed for the medium range launch vehicle under consideration. 展开更多
关键词 再入飞行器 载荷分析 最佳轨迹 翼身组合体 形状 最优控制问题 控制要求 运载火箭
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Influence of confined water on the limit support pressure of tunnel face in weakly water-rich strata
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作者 LI Yun-fa WU Guo-jun +2 位作者 CHEN Wei-zhong YUAN Jing-qiang HUO Meng-zhe 《Journal of Central South University》 SCIE EI CAS CSCD 2024年第8期2844-2859,共16页
In the process of shield tunneling through soft soil layers,the presence of confined water ahead poses a significant threat to the stability of the tunnel face.Therefore,it is crucial to consider the impact of confine... In the process of shield tunneling through soft soil layers,the presence of confined water ahead poses a significant threat to the stability of the tunnel face.Therefore,it is crucial to consider the impact of confined water on the limit support pressure of the tunnel face.This study employed the finite element method(FEM)to analyze the limit support pressure of shield tunnel face instability within a pressurized water-containing layer.Subsequently,a multiple linear regression approach was applied to derive a concise solution formula for the limit support pressure,incorporating various influencing factors.The analysis yields the following conclusions:1)The influence of confined water on the instability mode of the tunnel face in soft soil layers makes the displacement response of the strata not significant when the face is unstable;2)The limit support pressure increases approximately linearly with the pressure head,shield tunnel diameter,and tunnel burial depth.And inversely proportional to the thickness of the impermeable layer,soil cohesion and internal friction angle;3)Through an engineering case study analysis,the results align well with those obtained from traditional theoretical methods,thereby validating the rationality of the equations proposed in this paper.Furthermore,the proposed equations overcome the limitation of traditional theoretical approaches considering the influence of changes in impermeable layer thickness.It can accurately depict the dynamic variation in the required limit support pressure to maintain the stability of the tunnel face during shield tunneling,thus better reflecting engineering reality. 展开更多
关键词 weakly water-rich strata confined aquifer limit support pressure finite element method multiple linear regression
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Stability analysis of three-dimensional two-bench unsaturated soil slopes under seismic loading
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作者 SHAN Jun-tao WU Yi-min YANG Xiao-li 《Journal of Central South University》 CSCD 2024年第11期4187-4202,共16页
Due to rainfall infiltration,groundwater activity,geological processes,and natural erosion,soil often exhibits heterogeneity and unsaturation.Additionally,seismic events can compromise slope stability.Existing analyti... Due to rainfall infiltration,groundwater activity,geological processes,and natural erosion,soil often exhibits heterogeneity and unsaturation.Additionally,seismic events can compromise slope stability.Existing analytical solutions typically consider a single failure mode,leading to inaccurate slope stability assessments.This study analyzes the impact of matric suction through three nonlinear shear strength models and adopts a heterogeneous soil model where cohesion linearly increases with depth.An improved pseudo-dynamic method is used to account for seismic effects.Based on a three-dimensional(3D)trumpet-shaped rotational failure mechanism,a new framework is established to analyze the stability of 3D two-bench slopes in heterogeneous unsaturated soil under seismic effects.The internal energy dissipation rate and external power at failure are calculated,and the gravity increase method is introduced to derive an explicit expression for the safety factor(F_(s)).The results are compared with previously published results,demonstrating the effectiveness of the proposed method.Sensitivity analyses on different parameters are conducted,discussing the influence of various factors on F s.This study proposes a new formula for calculating the F_(s) of 3D two-bench slopes in heterogeneous unsaturated soil under seismic effects,providing a practical application for slope engineering. 展开更多
关键词 3D two-bench slope limit analysis modified pseudo-dynamic method HETEROGENEITY UNSATURATION
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危岩体稳定性分析的三维极限平衡法 被引量:1
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作者 苏国韶 刘本朝 +1 位作者 刘友能 范秋雁 《金属矿山》 北大核心 2025年第1期72-80,共9页
针对二维极限平衡法不完全适用于三维危岩体稳定性分析的问题,根据极限平衡理论,考虑结构面宽度方向两侧贯通程度不一致时危岩体具有侧向扭转倾向的情况,提出了一种改进的危岩稳定性分析的三维极限平衡法。该方法通过对危岩体主控结构... 针对二维极限平衡法不完全适用于三维危岩体稳定性分析的问题,根据极限平衡理论,考虑结构面宽度方向两侧贯通程度不一致时危岩体具有侧向扭转倾向的情况,提出了一种改进的危岩稳定性分析的三维极限平衡法。该方法通过对危岩体主控结构面进行拉伸拓展,得到三维计算简图,进而对三维计算简图进行受力分析,计算其抗滑(扭)力(矩)和滑动(扭转)力(矩)的比值,得出了滑移式、坠落式和倾倒式3类危岩相应的稳定性系数计算公式,依据所提公式与数值模拟分析了侧向贯通率及上部贯通率对危岩稳定性的影响。研究表明:随着侧向贯通率及上部贯通率增大,危岩体稳定性呈下降趋势。相较于传统的二维极限平衡法,所提方法计算精度更高,计算相对误差降低了50%以上,并且能够同时适用于主控结构面竖向与侧向完全贯通条件与不完全贯通条件下的危岩稳定性分析,有效解决了现行规范推荐的二维极限平衡法无法考虑主控结构面侧向贯通影响的问题,扩展了二维极限平衡分析方法的适用范围,丰富了危岩稳定性分析理论。 展开更多
关键词 危岩 崩塌 稳定性系数 极限平衡法
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我国宠物饲料安全风险及监管中亟待解决的问题 被引量:1
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作者 孙国荣 陈磊 +1 位作者 金琦琦 周静 《中国饲料》 北大核心 2025年第1期153-156,共4页
近年来,我国宠物饲料行业发展的规模和速度惊人,市场份额不断增大,同时也显露出不少问题。本文侧重于宠物饲料质量安全,从宠物营养要求特点出发,对存在的有害微生物、霉菌毒素、药物及添加剂、有毒有害元素等风险因素进行分析总结,同时... 近年来,我国宠物饲料行业发展的规模和速度惊人,市场份额不断增大,同时也显露出不少问题。本文侧重于宠物饲料质量安全,从宠物营养要求特点出发,对存在的有害微生物、霉菌毒素、药物及添加剂、有毒有害元素等风险因素进行分析总结,同时提出质量安全监管中限量标准、检测方法和监管体系中存在的亟待解决的问题,希望对生产加工、科研开发、监管工作提供参考。 展开更多
关键词 宠物饲料 质量安全 风险因素 限量标准 检测方法 风险监管
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热分析获取锅炉内煤着火特性—Part Ⅰ:比热容、着火温度和着火热 被引量:1
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作者 刘洋 石泽正 +7 位作者 陈朝帅 苟皓语 陶继业 徐世明 余波 赵培涛 傅培舫 周怀春 《煤炭学报》 北大核心 2025年第2期1303-1314,共12页
现有热分析获取的煤/低温热解焦着火温度值比锅炉内煤着火温度低200~300 K,普遍观点认为热分析仪的升温速率β过低是导致上述结果的主因,但其本质原因应是以往的研究选择的样品反应性过高而导致煤/焦着火提前,同时常用的TG-DTG切线法求... 现有热分析获取的煤/低温热解焦着火温度值比锅炉内煤着火温度低200~300 K,普遍观点认为热分析仪的升温速率β过低是导致上述结果的主因,但其本质原因应是以往的研究选择的样品反应性过高而导致煤/焦着火提前,同时常用的TG-DTG切线法求着火温度不够准确。为解决上述问题,采用非等温TG-DSC获取了2种高温(1400℃)快速热解准东煤焦在不同β下的着火特性包括比热容、着火温度和着火热,考察了β对煤焦着火特性的影响。采用David Merrick模型获取了煤焦的比热容,发现其不受β的影响但与温度的变化相关;用指数函数描述了比热容与温度的关系,得到2种煤焦在0~1600℃的比热容为0.65~1.99 kJ/(kg·K)。采用基于Semenov热爆炸理论的DSC或DTG拐点法和TG-DTG切线法获取了煤焦的着火温度,发现DSC拐点法和DTG拐点法获取的着火温度相当,即两者具有等效性,且始终高于TG-DTG切线法获得的着火温度;着火温度随着β的增加而增加,但增加幅度逐渐减少,可用指数函数描述。将β设置为锅炉中常见的升温速率如105 K/s,可获得煤焦的极限着火温度。采用DSC拐点法和TG-DTG切线法获得的煤焦极限着火温度分别为673~680℃和644~659℃,前者与文献中在携带流反应器(类似锅炉环境)中获得的同类型煤样的着火温度值一致,而后者则会低估着火温度。结合高温热解焦比煤/低温热解焦的反应性低的事实,指出制取反应性合适的高温热解(类似锅炉环境温度)煤焦样品和采用DSC或DTG拐点法获取煤焦的极限着火温度可实现热分析对锅炉内煤着火温度的预测。根据极限着火温度获取了锅炉内2种煤焦的着火热q_(ig)为3414~3669 kJ/kg,并计算了风煤比为0.9~2.5下2种煤焦的理论着火热为1826~2811 kJ/kg。q_(ig)比相应煤焦的理论着火热值大,表明理论着火热可能高估煤在锅炉内的实际着火能力。对热分析获取锅炉内煤着火特性的合理性进行了全方位诠释,所提出的热分析方法论可为获取CFD模拟锅炉内煤着火特性所需的基础数据提供参考。 展开更多
关键词 热分析 DSC拐点法 极限着火温度 着火热 比热容 升温速率 准东煤
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考虑场地效应的多点地震动作用下边坡永久位移分析
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作者 宋健 潘驭航 +3 位作者 陆朱汐 姬建 张飞 高玉峰 《岩土工程学报》 EI CAS 北大核心 2025年第1期65-75,共11页
地震动引起的边坡土层非线性动力响应可能导致坡体不同位置的地震动加速度时程不一致,从而对整个滑动体的极限平衡状态及之后的地震累积永久位移产生影响。为了研究场地效应对边坡地震永久位移的影响,基于极限平衡条分法,通过对不同土... 地震动引起的边坡土层非线性动力响应可能导致坡体不同位置的地震动加速度时程不一致,从而对整个滑动体的极限平衡状态及之后的地震累积永久位移产生影响。为了研究场地效应对边坡地震永久位移的影响,基于极限平衡条分法,通过对不同土条赋予不同的水平和竖向地震动时程,推导出一种考虑场地效应的圆弧和任意形状滑面的多点地震作用下边坡永久位移分析方法。通过与有限差分软件FLAC的数值模拟结果进行对比,验证了该方法能够合理考虑地震动的场地效应。通过研究不同分布形式的多点地震动及竖向地震动对边坡永久位移的影响,结果表明:场地效应引起的水平地震动放大以及多点地震动不同分布模式会导致整个滑体平均地震惯性力作用位置发生改变,从而影响地震作用下滑动体沿滑面的永久变形量,竖向地震动对边坡地震位移影响较小。将方法应用于Lexington土石坝震后变形案例分析,计算得到的坝坡地震永久位移与实际震后观测值相吻合,证明了考虑场地效应的重要性及本文方法的合理性。 展开更多
关键词 地震边坡稳定性 场地效应 永久位移 极限平衡条分法 多点地震动
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卸荷损伤效应下开挖边坡稳定性极限平衡分析 被引量:2
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作者 邓东平 石柱 彭文耀 《工程地质学报》 北大核心 2025年第1期327-340,共14页
边坡开挖卸荷在一定程度上会引起坡体内岩土体强度产生损伤,进而影响到开挖边坡稳定性。当前,边坡工程开挖滑塌事故频有发生,而较少研究关注卸荷损伤效应下开挖边坡稳定性分析。在此,基于简单的线性模型,建立开挖卸荷效应下边坡滑面岩... 边坡开挖卸荷在一定程度上会引起坡体内岩土体强度产生损伤,进而影响到开挖边坡稳定性。当前,边坡工程开挖滑塌事故频有发生,而较少研究关注卸荷损伤效应下开挖边坡稳定性分析。在此,基于简单的线性模型,建立开挖卸荷效应下边坡滑面岩土体强度参数计算公式。进而,结合极限平衡推力法,引入迭代计算策略,实现边坡安全系数反馈与滑面强度参数更新之间的交互计算,达到卸荷损伤效应下开挖边坡稳定性分析的目的,为工程边坡开挖过程中安全状态评估提供科学依据。此后,经3种不同类型开挖边坡算例对比分析,验证了本文方法的可行性。研究表明,开挖卸荷损伤明显降低开挖后边坡稳定性,且边坡破坏形态可能会演变成近坡面的浅层失效。 展开更多
关键词 开挖边坡稳定性 卸荷损伤 滑面强度参数 极限平衡推力法 安全系数 滑动面
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有限水域中运动声源全息反演方法研究
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作者 张小正 庞业珍 +3 位作者 毕传兴 张凤敏 沈洋 李志超 《船舶力学》 北大核心 2025年第8期1299-1308,共10页
采用声全息技术开展有限水域中运动声源识别及其声场预测,对于研究水下航行器的声源特性和声辐射特性具有重要意义。然而,运动声源辐射声压的获取和有限水域界面效应的影响给声全息技术在有限水域中的应用带来了困难。本文考虑声源运动... 采用声全息技术开展有限水域中运动声源识别及其声场预测,对于研究水下航行器的声源特性和声辐射特性具有重要意义。然而,运动声源辐射声压的获取和有限水域界面效应的影响给声全息技术在有限水域中的应用带来了困难。本文考虑声源运动,采用线阵测量并基于移动框架技术来获取运动声源辐射的全息面声压数据;考虑有限水域界面效应的影响,在三种不同界面情况下,基于等效源法思想分别构建了三种全息反演模型。以有限水域中的圆柱壳体为对象开展了数值仿真,结果表明,三种反演方法相较于未考虑界面反射的自由场反演方法可以获得更好的声源识别和声场预测效果。在湖中开展了运动标准声源试验,试验结果表明,所建方法可以实现声源的有效定位和声场的精确预测。 展开更多
关键词 声全息 有限水域 运动声源 等效源法
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一种水电机组调速系统稳定性分析方法及超低频振荡抑制
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作者 汪芳宗 余坤 李默 《中国电机工程学报》 北大核心 2025年第10期3858-3864,I0024,共8页
水电机组调速系统包含死区以及限幅环节,是一个典型的非光滑动力系统,也是一个线性切换系统。若控制参数设置不合理,切换系统将产生切换振荡现象。水电机组调速系统已多次出现与调速死区及限幅相关的超低频频率振荡问题。目前,为分析水... 水电机组调速系统包含死区以及限幅环节,是一个典型的非光滑动力系统,也是一个线性切换系统。若控制参数设置不合理,切换系统将产生切换振荡现象。水电机组调速系统已多次出现与调速死区及限幅相关的超低频频率振荡问题。目前,为分析水电机组调速系统的稳定性,主要采用描述函数法,但描述函数法是一种频域工程近似方法,在实际应用中需满足一定的前提条件。为解决超低频振荡问题,该文提出一种基于时域状态空间的稳定性分析新方法,并给出相应的理论证明。该方法既可用于一般光滑动力系统的稳定性分析,也可应用于间断微分系统。将该方法应用于水电机组调速系统的稳定性分析及控制参数的优化设计,可以彻底避免超低频振荡现象。算例结果验证该方法的有效性。 展开更多
关键词 水电机组 调速系统 线性切换系统 超低频振荡 极限环 描述函数法 Filippov方法
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融合寿命信息与多性能退化信息的元动作单元可靠性评估
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作者 冉琰 吉昱 朱晓 《湖南大学学报(自然科学版)》 北大核心 2025年第2期109-121,共13页
针对机床可靠性建模困难、可靠性数据匮乏等问题,从元动作单元出发,提出一种融合寿命信息与多性能退化信息的可靠性评估方法.利用“功能—运动—动作”(functionmotion-action,FMA)分解法将机床分解至最小运动单元,即元动作单元,机床的... 针对机床可靠性建模困难、可靠性数据匮乏等问题,从元动作单元出发,提出一种融合寿命信息与多性能退化信息的可靠性评估方法.利用“功能—运动—动作”(functionmotion-action,FMA)分解法将机床分解至最小运动单元,即元动作单元,机床的可靠性水平通过准确评估关键元动作单元的可靠性来保证.建立随机效应下非线性Wiener过程的性能退化模型,刻画试验样本退化过程存在的个体差异性、共同属性以及退化过程的非线性,在此基础上针对退化数据不足的问题,利用贝叶斯方法建立融合失效寿命信息的可靠性模型.考虑多性能退化失效相关性,基于Copula函数建立多性能退化可靠性评估模型,利用MCMC-Gibbs抽样算法实现参数估计.以某型号数控滚齿机的蜗杆转动元动作单元为研究对象,通过实例分析以及验证对比表明所提可靠性评估方法的可行性和优越性. 展开更多
关键词 可靠性 信息融合 随机过程 元动作单元 贝叶斯方法
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