西南交通大学学报

On the Speeding-up of China' s Railway Construction

Cai Qinghua

1999, 12(1): 1-5.

[Abstract](1533)

Abstract:
The importance of speeding-up railway construction with respect to the inter- national and domestic economic conditions and the significance of the railway develop- ment itself is pointed out. A general plan and principles of railway construction are pre- sented and discussed in detail.

Study on the Crack Deformation of Tunnel 105 on Baoji-Tianshui Railway

Hu Houtian, Kongjian

1999, 12(1): 6-10.

[Abstract](1691)

Abstract:
Based on the investigation of the engineering geological environment and the long-term monitoring of tunnel cracks, the surrounding rock of tunnel 105 is proved to be a slack rock mass. A long-term gradual creep of the slack rock is the essence of the crack deformation of the tunnel, which are resulted from stress relaxation, earth surface scouring, rock collapses, landslides, underground water process and tunnel construction, etc.

A Mathematical Model for the Coupling among Groundwater Seepage-Stress-Temperature in Engineering Rock Mass

Huang Tao, Yang Lizhong, Chen Yili

1999, 12(1): 12-15.

[Abstract](1561)

Abstract:
Engineering rock mass is located in the complex geological environment where groundwater seepage field, stress field and temperature field exist simultaneously. In order to study the mutual actions among the above fields, a simple mathematical model of coupling among them is tentatively built through the study of coupling mechanism among equivalent function fields based on the principle of field properties' equivalence. It supplies a reference for the quantitative study of the coupling among these three fields.

Experimental Study on the Compaction Grouting of Pile Tip in Loess Region

WangXu, Wu Xingxu, Zhao Shanrui

1999, 12(1): 16-21.

[Abstract](1364)

Abstract:
In this paper, the compaction grouting technology which is used to enhance the bearing capability of cast-in-place piles in a loess region is experimentally studied based on a static test in which some detectors are attached in situ along the test pile. Some problems of the applications of the grouting method in the loess region are also discussed. The bearing capability properties of the cast-in-place pile of a pile tip compaction grouting are analyzed, so as to provide references for the application of the technology in loess regions. Meanwhile, the bearing capability of the cast-in-situ pile is compared with that of piles cast according to codes.

Functions of a System for Processing the Information of Surface Movement

Li Yongshu, ZhuoJiancheng, Liu Wenxi

1999, 12(1): 22-26.

[Abstract](1275)

Abstract:
The functions of a system for processing the information of surface movement are expounded. Based on the formula for the prediction of subsidence, incline deformation, curvature deformation, level movement, horizontal deformation, the mined area of seams and the area and volume of subsidence troughs, and for the calculation of predicting parameters, all application softwares for calculation and management are programmed. The softwares are tested comprehensively with computer techniques, and verified with measured data. The results show that the system for processing the information of surface movement meets the design requirements.

Joint Acceptance Function for Determining the Buffeting Response of Bridges

Jiang Yonglin, LiaoHaili, Qiang Shizhong

1999, 12(1): 27-31.

[Abstract](1473)

Abstract:
The span-wise coherence function of the aerodynamic lifting force in the buffeting response of bridges is analyzed by using the lifting-surface theory of airfoils. Result shows that the values of the coherence function are larger than those of the on- coming span-wise wind velocity fluctuation, and the strip assumption has limitation in some instances. Because the joint acceptance function based on the strip assumption underestimates the response of structures to the wind force, a coherence function for the aerodynamic lifting force along the span-wise direction is proposed , which is fit to be used in the calculation of the joint acceptance function for the buffeting response of bridges.

Non-Linear Stability Analysis of a Concrete Arch Bridge on Its Construction Stage

Xie Shangying, Qian Dongsheng

1999, 12(1): 32-35.

[Abstract](1486)

Abstract:
This paper discusses the construction characteristics of reinforced concrete arch bridge with stiff skeleton of concrete-filled steel tubes. With the use of load incremental method and with the considerations of the effects of geometrical and material non-linearity and the loading process of construction, three computation models are built to analyze the stability of every construction stage of a long-span concrete arch bridge with stiff reinforcement. The scopes of application of the various computation models are also presented.

Study on Optimization of the Composition of Funds Collected for the Construction of Low-Interest Dwelling Houses

Huang Yunde, He Xiaogui

1999, 12(1): 36-41.

[Abstract](893)

Abstract:
Based on the characteristics of the development of low-interest dwelling houses, various ways to collect the funds for the construction of such houses are investigated. Having analyzed the Factors influencing the composition of the raised funds, a mathematical model for optimizing the composition of the funds is built. Moreover, by employing the functional relation betweeni(interest of the raised funds) andX(amount of the raised funds), and that betweenXandr(reliability of the funds), together with measures for discretizating of the upper and lower limits of soft confinementbi, a simplified model is deduced, with the method of solving it discussed.

Analysis of Transient Electromagnetic Scattering for Railway Ballast

Wu Wentao, LiJing　Qin Jun

1999, 12(1): 42-46.

[Abstract](1274)

Abstract:
A discrete model for random media is employed to simulate the distribution of railway ballast. The calculation simulation model for railway ballast is built by random filling in the meshes of FDTD method, and the intensities of the transient electromagnetic scattering field are calculated. Then the incoherent scattering field is calculated and analyzed to obtain the electromagnetic parameters for the distribution of the railway ballast. The numerical analysis result shows that there exists an exponential function relationship in a certain range between the obtained parameters and the porosity of railway ballast. Therefore, it can be concluded that applying the electromagnetic technology to detect the porosity of railway ballast is possible.

On Stability and Reliability of a Universal Decision Making System

Jiang Gefu, He Ping

1999, 12(1): 47-50.

[Abstract](1639)

Abstract:
The decision making in respect of a system usually means to decide relevant tactics based on a good grasp and analysis of the past records and the present condition about its background system. Therefore, the effect of the decision depends on not only the reasonableness of the tactics but also to a large extent on the dynamic stability of the background system. In this paper, concepts about the stability of a system and the reliability of decision making are proposed for a universal decision system based on a quantitative analysis. A set of simple stability measures for the decision making system and criteria for the reliability of the decision making are presented. The proposed measures and criteria can be used as the precondition of decision making and inspection basis for a universal system.

On Ultrafilters of Lattice Implication Algebras

Qin Keyun, Xu Yang

1999, 12(1): 52-54.

[Abstract](1197)

Abstract:
In model theories, constructing ultraproducts by ultrafilter is an important method for model construction. In this paper, the concept of ultrafilter of lattice implication algebras is proposed. The relationship between ultrafilters and prime filters, and the one between ultrafilters and finite intersection properties are discussed. The equivalence between ultrafilter and maximal proper filter is proved. It provides a foundation for studying the corresponding ultraproduct theory.

Complex-Rotary Codes of Genusg=1

Zhang Aili, Jin Fan, Liu Xiufeng

1999, 12(1): 55-60.

[Abstract](1326)

Abstract:
The concept of complex-rotary codes of genusg=1 is proposed in this paper. By means of the complete embedding of multi-layer ring surfaces, a visual model of GICR codes is given. The codes are the extension of complex-rotary codes from 2- dimensional space to 3-dimensional space. By using the conception of the weak block design, the minimum distance and error-correcting capability of the codes are discussed. Meanwhile, the dual codes of GICR codes are studied, and the main parameters of GICR codes and their dual codes are also presented.

A Method for Forecasting the Prices of Mechanical and Electric Products

YiJianhua

1999, 12(1): 61-64.

[Abstract](1230)

Abstract:
Multivariate regression analysis is employed to predict the prices of mechanical and electric products according to historical prices. Because there are many years in which the product price data are unavailable, a price index is introduced into the prediction. Thus, the problem of forecasting the product prices is converted into the one of forecasting the price indexes. In the regression analysis, the time and price policies are taken as significant factors of the price index. The characteristics of the fitting values of the price index are also discussed.

The Growth Mode of Lower Bainite in Silicon Containing Steel —The Shear Thickening of Lower Bainite

ZhangXiya, Wu Xiaole, Kang Mokuang

1999, 12(1): 65-70.

[Abstract](1236)

Abstract:
The diffusion controlled ledge growth mechanism of bainite (DCLGMB) is reviewed briefly in this paper. It is argued that the existence of the ledge can not prove the existence of DCLGMB. A growth mode of lower bainite by shearing on the stacking fault face of austenite is proposed. In this mode, the thickening of lower bainite depends on the interfacial misfit dislocation loop (IMDL), which expands on the stacking fault faces of austenite. Ledges move only along the stacking fault faces but not along the side direction, and the side faces of ledges are not incoherent boundary. The observed experimental phenomenon of the austenitic stacking fault fringes corresponding to the lower bainitic growth ledges can be explained by the shear thickening mode.

In Situ Synthesized TiB2-TiC-SiC Ceramic Composite

Zhu Degui, Yin Xiandong, Xiao Chuanchun

1999, 12(1): 71-75.

[Abstract](1248)

Abstract:
TiB2-TiC-SiC composite is in-situ synthesized with the use of TiH2, Si and B4C power blend under hot isostatic pressing. The fracture toughness of the fabricated composite is 7.3 MPa·m1/2. The microstructure and morphology of the composite are studied with SEM and TEM. It is shown that the grain sizes of TiB2, TiC and SiC phases are less than 10μm, and the interfaces of the three phases are clean. TiC and SiC grains are irregular polygons and TiB2grains regular platelets. The SEM analyses of the fractured surfaces suggest that transgranular fracture happened to coarse grains, and intergranular fracture to the rest of grains. Particle reinforcement, crack deflection and particle pullout are the main toughening mechanisms.

Study on the Surface Activity of the Copolymer Surfactant PVA-MA-PEGA

Qi Linlin, Wang We, Li Zhiming

1999, 12(1): 76-81.

[Abstract](991)

Abstract:
The critical micelle concentration (CMC), surface tension and interfacial tension of a copolymer are investigated. The copolymer is synthesized by the copolymerization of polyvinyl alcohol (PVA), methyl acrylate (MA) and polyethylene glycol acrylates (PEGA) in aqueous solution and has a certain surface activity. The interactions between the polymer and the OP series low-molecular surfactant are also discussed. It is found that with the increase of the content of the hydrophobic monomers, the hydrophobicity of the polymer molecules increases and the value of CMC decreases. When the copolymer surfactants are compounded with low-molecular non- ionic surfactant OP10, the system achieves the minimum surface tension 30.6 mN/m, and the minimum interfacial tension 0.36 mN/m respectively.

A Study on Static Stability of Permanent Maglev Mechanisms with Permanent Magnets

Liu Shangju

1999, 12(1): 82-86.

[Abstract](1414)

Abstract:
Three mechanisms, magnetically levitated by permanent magnets are introduced and analyzed in respect of their balance and stability based on the nature of attraction and repulsion by permanent magnets. The barycenter of the vehicle body is above the magnetic suspension mechanism in one mechanism, below it in the another two. The analysis shows that, among the three mechanisms presented in this paper, the suspension mechanism combining magnetic attraction and repulsion can be statically stable, while the other two can not.

Real-Time Observation and Analysis of Meso-Fracture Behavior of Marble Samples

Jiang Chongx, Xie Qian

1999, 12(1): 89-92.

[Abstract](1245)

Abstract:
A real-time and dynamic investigation of the meso-fracture behavior and strength characteristics of marble samples is carried out under a scanning electric microscope (SEM) instrumented with axial tensile/compression loading device of high precision. The influences of marble initial meso-fabric, the influences of stresses to the initial meso-fabric and magnitude of stress of the marble on the fracture creating and its pattern of extending are discussed. Also discussed is the relationship between the mechanical behavior of meso-fracture and the macro-mechanical performances. The method of preparing the rock samples used for the axial compression loading test under the SEM is also introduced.

Analysis of Driving-Braking Unit System of High Speed Power Bogie with Hollow-Axles and Wheelset

Zhong Wensheng　, ZhangHongjun

1999, 12(1): 93-98.

[Abstract](1635)

Abstract:
The composition, structure characteristics and suspension pattern of a driving-braking unit system used in high speed power bogie with double hollow axles is analyzed in this paper. During the process of motion, the relative movement between the unit and its adjacent components is analyzed and calculated in detail. It is proved that this new type of driving-braking system can satisfy the kinematical requirements of the high-speed power bogies, with the body suspension of the driving motor being achieved.

Experimental Study on Lateral Active Suspension in Railway Vehicles

Zhang Kailin, Duan Zhiyong

1999, 12(1): 99-103.

[Abstract](1523)

Abstract:
A one-eighth scale half vehicle lateral active suspension experimental model with four degrees of freedom is established. The active suspension and passive suspension experiments are comparatively studied with LQR control law, and the experimental results is comparied with the simulation results. It is shown that the active suspension can effectively attenuate vibration, especially the vibration at the resonant frequency. Compared with the passive suspension, the amplitudes of the lateral and roll vibrations of the car body are reduced by 80% and 65% respectively on the average at high frequency resonant band in active suspension, and 30% and 25% respectively on the average at the rest of the frequency band.

Lightening Assessment and Fatigue Strength Analysis for the Welded Frame of Locomotive Bogies

Mi Caiying

1999, 12(1): 104-108.

[Abstract](1484)

Abstract:
The rule for assessing the lightening of welded frame of Bo-Bo locomotive bogie is proposed. Based on the analysis result of the frame s whole structure with finite element method, the stress distribution in the lateral butt-weld on the bottom cover plate of the side beam of the frame is analyzed with boundary element method. The stress concentration due to the incomplete penetration root of the weld is discussed, and a feasible scheme to reduce the stress in the tensile butt-weld is presented. A comparison between the results of the theoretical analysis and fatigue intensity tests shows that the stress distribution in the weld region can be calculated accurately with boundary element method.

Reliability Simulation Analysis of the Dislodging Restrict Appraisal Mode

Tang Li, Wu Jingye

1999, 12(1): 109-114.

[Abstract](1572)

Abstract:
The operational mechanism of the dislodged restrict appraisal mode and its impacts to the reliability of appraisal results are analyzed in this paper, creating a new method for appraisal reliability analysis. By reasoning of the results of from simple dislodged restrict appraisals to common dislodged restrict appraisals, and analyzing the location precision of the appraisal results with simulation method, two important results of reliability appraisal under the dislodged restrict appraisal mode are obtained, which lay a basis for experts to fully exert specialties and restrain subjective random.

A Productivity Management System Model and Its Application

Wang Yaping, Zhao Dongmei, SongJirong

1999, 12(1): 116-119.

[Abstract](1405)

Abstract:
A theoretical model for the productivity estimate and management system (PEMS) of engineering items is proposed based on the concept of productivity management with its operational mechanism described. Meanwhile, combined with the practice of engineering items, a practical model for the measure, prediction and improvement (MPI) of productivity is built under the guidance of the proposed theoretical model. The analysis of the application of the MPI model into an engineering example shows that the model is characterized by simplicity and effectiveness, and be suitable for the spot application of engineering items. The calculation result provides a basis for contractors to recognize and analyze the construction claims for losses resulted from the productivity decrease, and to control and improve the productivity.

An Optimum Decision Support System for Project Construction Plan

Lin Jie, Guo Yaohua

1999, 12(1): 121-125.

[Abstract](1382)

Abstract:
In order to arrange the progress of engineering constructions rationally and make optimal use of resources, subjects such as operational research, economics, engineering science, decision making management,etc. are used comprehensively on a man-computer interactive system to produce an optimum decision support system for project construction plan (PODSS). The functions, structure and main models of the system are described and elaborated, with the corresponding software developed. The experimental result shows that the system can provide an assist management and decision-making environment for the planners of engineering construction projects and spot managers, and is an effective technological tool for construction firms to make scientific decision.

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1999 Vol. 12, No. 1