Table of Content

    30 May 2011, Volume 45 Issue 05 Previous Issue    Next Issue
    Communication and Transportation
    Influence of Slope on Slurry Diffusion in Grouting Treatment of Immersed Tunnel
    LI Ke, DU Jia-Lun, HUANG Xing-Chun
    2011, 45 (05):  629-633. 
    Abstract ( 3507 )   Save
    Slopes caused by unevenness of cushion or tunnel design will affect slurry diffusion, when adopting grouting method in foundation treatment of immersed tunnel. Model test was conducted to study slurry diffusion of singlehole and dualhole grouting with different slopes. It was indicated that diffusion velocity along downhill direction would be larger than that along uphill direction apparently, which shows that the flow of slurry is influenced by the gravity obviously, trending to the lower position. With the larger slope, the difference between diffusion velocity along uphill and downhill direction would be greater. Based on the test result, it ought to inject at the lowest grouting hole firstly, and along the uphill direction in turn, to avoid voids.
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    Analysis on Interaction Mechanism between Tunnel Structure and
    Surrounding Soil under Action of Vertical Groundfissure
    SHAO Sheng-Jun, SHE Fang-Tao, ZHENG Wan-Kun
    2011, 45 (05):  634-638. 
    Abstract ( 4542 )   Save
     The displacement input condition was obtained by the sunken settlement distribution character of ground fissure. The excavation construction, lining structure section and largedisplacement of ground fissure passed vertically by a subway tunnel were simulated by the numerical calculation of DFM. The characteristics of tunnels structure and surrounding soil mass were analyzed by strata settlement, lining structure sections displacement, earth pressure on lining structure and its internal forces. The research indicates that in the condition of ground fissure movement with sunken character, settlement deformation happens mainly in the soil mass located above the ground fissure. The vertical earth pressure under the bottom of lining structure located in the soil mass above ground fissure significantly reduces. The axial stress at the end of lining structure sections increases remarkably. On the one hand, the clearance between lining structure sections can adapt the ground fissure movement and avoid the failure of lining structure, on the other hand, the lining structure sections can inhibit the deformation of strata with active ground fissure, and reduce the relative displacement adjacent lining structure sections at fissure. The measure of tunnel with lining structure section would improve the operation conditions of the ground fissure subway tunnel.
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    Structure Inner Force Analysis of Electric Cable  Tunnel under Special Loads
    WANG Xin-1, 2 , ZHANG Qing-He-1, 2 , ZHOU Jin-Hai-3
    2011, 45 (05):  639-642. 
    Abstract ( 3796 )   Save
    The use of the electric cable tunnel is different from that of metro tunnel, and also its inner loads. Based on Shanghai electric tunnel project, the structure inner force under inner and out loads was analyzed, and the calculating model should be used that have the ability to deal with changeable structure and varying loads. The analysis results show that, after the assembly of the cross beam and under corresponding inner loads, the axial force of shield tunnel segment increases; and the segment moment decreases in upper part, but increases in lower part; the moment that joint element bears decreases.
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    Study on Nuclear Blast Damage to RiverCrossing Tunnel in Shanghai
    XIAO Li, ZHANG Qing-He
    2011, 45 (05):  643-647. 
    Abstract ( 3308 )   Save
    Based on the river-crossing tunnel of Xiangyin road in Shanghai,elastic modulus and resistant coefficient of soil were analyzed with dynamic tri-axial test under the condition of nuclear blast. The results show that two parameters increase significantly. Load and structure model was performed and internal force of tunnel  was calculated in different load conditions. The results indicate that protective door can improve the anti-nuclear blast capability of tunnel structure and the river-crossing tunnel can meet the requirement of bearing capacity under grade-6 civil defense load.
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    Evaluation of Mudjack Method Filling Effect of Immersed Tube Tunnel Using Surface Wave Survey Method
    CHE Ai-Lan-1, HUANG Xing-Chun-1, GUO Qiang-1, FENG Shao-Kong-2
    2011, 45 (05):  648-652. 
    Abstract ( 3807 )   Save
    Based on large-scale test model of the Haihe immersed tube tunnel locating at the centre avenue of Tianjin city, the application study of surface wave survey method, used for detecting filling effect of its underwater pressure casting foundation, was carried out. Considering the frequency characteristic and site environment of the tunnel, the types and qualification of equipments for surface wave survey were selected, setup and arrangement of detectors were optimized, and the equipment configuration and construction practices of fast nondestructive testing for tunnels were developed. The filling effect of mudjack method on tunnel foundation was estimated synthetically by surface wave survey in-situ dispersion and inverse analysis. Moreover, comparing the visual results when the test model removed, the practicability of this new survey techniques and analysis methods was verified. The test results show that this surface wave survey method can detect thick concrete filling without influence of reinforcing bars, and detect mud-jack method filling effect of immersed tube tunnel fast and correctly.
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    Deformation Behaviors and Bearing Capacity of  GeosyntheticsReinforced Pavement
    SONG Guang, BIAN Xue-Cheng, JIANG Jian-Qun, CHEN Yun-Min
    2011, 45 (05):  653-658. 
    Abstract ( 3448 )   Save
    A simplified analysis model considering two-parameter ground model and the Coulomb friction assumption was proposed to investigate reinforced pavement’s deformation behaviours and bearing capacity. The computation results show that geosynthetics constructed in pavement can reduce about 50% depth of granular filling layer for same pavement deformation. The peak value of tensile strain in geosynthetics appears in 1.5-2.0 times of load range. The bearing capacity of reinforced pavement increases by 15% compared to non-reinforced pavement when the bending stiffness of geosynthetics is taken 0. Pavement’s bearing capacity improves greatly with increasing geosynthetics bending stiffness. In addition, the bearing capacity of pavement can be increased by 33% approximately in the case of same depth of granular fill.
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    Permanent Deformation Computation Research of Graded Gravel Base in Flexible Pavement
    WANG Xiu-Shan-1, 2 , DING Xiao-Jun-1, XIE Yong-Li-2
    2011, 45 (05):  659-661. 
    Abstract ( 4680 )   Save
    Based on repeatedly dynamic triaxial test result fitting, using the Kenlayer computational procedure and the 1stopt statistical analysis software, the nonlinear regression and fitting were carried out. One permanent deformation computational method of flexible pavement graded gravel base under the vehicles axle load repeatedly function was established. A scene correction coefficient was introduced to modify the indoor permanent deformation estimate model. The permanent deformation of flexible pavement graded gravel base may be directly calculated through the regression formula proposed in this article. And it can be used to forecast Chinese asphalt pavement rutting.
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    Dynamics Response Characteristics of LongLife Asphalt Pavement  under Different Axial Load and Movement State
    LI Ting-Ting-1, 2
    2011, 45 (05):  662-666. 
    Abstract ( 3373 )   Save
    Based on the typical construction of long-life asphalt pavement, a simplified three-dimensional dynamics model was built up. The axial loads of light, middle and heavy type of vehicles were considered. Numerical simulation was applied to study the response of dynamics parameters in the function layers with inducting the movement state of steady or brake. The computational results show that the horizontal stress and strain are concentrated near the edge of the load circle, while the vertical displacement occurrs inside the load circle. The horizontal load induced by brake will enhance the concentrating of horizontal stress and strain, but its effect on vertical strain and displacement is limited. The vertical load is the most important factor to test the performance of the pavement, which plays dominate role in determining vertical strain and displacement.
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    Analyses of Inner Air Void Characters in Composite Asphalt  Concrete Based on CT Technology
    WANG Zhen-Jun-a, SHA Ai-Min-a, b , XIAO Jing-Jing-b, JIANG Wei-b, WANG Rui-a
    2011, 45 (05):  667-671. 
    Abstract ( 3859 )   Save
    X-ray computed tomography (CT) technology was adopted to analyze change rules of air void number, air void size and air void ratio of 1-10 slices in the concrete with the same aggregate gradation and scanning electron microscope (SEM) was used to analyze its mechanism. The results indicate that there are more air void numbers, larger air void size and higher air void ratio in the sides of the same concrete specimens, while they are the opposite in the middle. The highest air void ratio is 10.1%. The addition of ordinary Portland cement or the adoption of asphalt emulsion with optional dosage is helpful to decrease the air void ratio. There exists the lowest air void ratio, 3.9%, in the concrete when the dosage of asphalt emulsion and cement is 8.0% and 3.0% respectively. The air void distribution is inhomogeneous.
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    Study on Ground Settlement Caused by Shield Tunneling Long Distance Across Multitracks
    XIAO Li, ZHANG Qing-He
    2011, 45 (05):  672-676. 
    Abstract ( 5113 )   Save
    Based on the bidsection of Binhai mass transit from Tianjin station to Qijing road station, 3DFEM was put forward to simulate shield tunneling long distance under multitracks of railway. According to the simulation results, settlement of ground surface along and perpendicular to the shield tunnel were analyzed. The disturbance area of ground and the settlement ratio dedicated by first tunnel and second tunnel were studied. The ground settlements caused by tunneling in different conditions were simulated and studied. The simulation results which fit well with monitoring data show that the maximum settlement of ground is between 18 mm and 20 mm. The influence of grouting amount is more significant than that of grouting pressure and soil pressure.
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    Comfort Evaluation and Vibration Reduction Design of  Long Span Footbridges
    QIAN Ji, SUN Li-Min
    2011, 45 (05):  677-681. 
    Abstract ( 3261 )   Save
    The fundamentals of pedestrianinduced vibration of footbridges were introduced, and a mechanics model of pedestrianinduced forces was presented under the condition of considering the pedestrianbridge interaction. According to the current research of long span footbridges, two comfort evaluation indexes of pedestrianinduced vibration were proposed. At the same time, a long span footbridge was used as an example to demonstrate the process of comfort evaluation. Considering the importance of this footbridge, a prescheme of vibrationreduction was designed based on tuned mass damper (TMD). The result illustrates that in this footbridge there is no pedestrianinduced vibration which exceeds comfort index.
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    Signal Optimization Method of Crosswalks  between Coordinated Intersections
    QU Zhao-Wei-1, LU Ting-1, WANG Dian-Hai-1, 2 , GUO Wei-Wei-1, SUN Di-1
    2011, 45 (05):  682-686. 
    Abstract ( 3463 )   Save
    This paper proposed the traffic signal optimization method for the midblock street crosswalk between coordinated adjacent intersections which introducing the pedestrian waiting tolerance limit time as one of the constraints of the signal timing optimization. The method takes the common red time of the two intersections as the crosswalk’s green time at first. If the common red time is not sufficient for the pedestrian crossing safely, it builds delay functions by using of motorcade dispersion and traffic flow rate relationship, and works out timing optimization parameter whose objective is to minimize the total vehicle delay. The result shows that this method may ensure the pedestrian crossing safety and reduce the pedestrian delay.
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    Pipeline Integrity Management System Based on  Dynamic Risk Assessment
    LIU Yu-Tao, HU Hao, SONG Yuan-Bin
    2011, 45 (05):  687-690. 
    Abstract ( 5072 )   Save
    A pipeline integrity management system was developed based on the theory of dynamic risk assessment in relevance to the unique characteristics of an oil/gas pipeline project. Furthermore, the cycle pattern of continuously updating integrity management was explored. The feasibility of applying integrity management system was then validated against the case with the close connections between a number of small cycles, indicating that the proposed integrity management system can better fulfill the requirements from dynamic management of pipeline safety.
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    Architechural Science
    Simulation on Properties of Curing Concrete After Strong Earthquake Effect
    WANG Ying-Yi, LI Ke, WU Hao-Ning, HUANG Xing-Chun
    2011, 45 (05):  691-695. 
    Abstract ( 3883 )   Save
     Curing concrete’s mechanical properties under the strong earthquake action and the influence of early strength agent on the seismic resistance of curing concrete were researched through simulating test. The results show that: ① the stressstrain relationship is linear at initial stage, then becomes nonlinear with the increasing load; ② the compressive strength of seismic vibrated concrete sample is significantly lower than that of common sample, so seismic vibration has a significant effect to concrete sample when curing time is less than certain time; ③ the early strength agent content has a clear effect on concrete in gelled state, the higher the content of early strength agent is, the faster the concrete hardens.
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    Application of Microtremor Method in Shear Wave Velocity  Structure Survey at Loess Regions
    WU Zhi-Jian-1, 2 , ZENG Li-Feng-1, WANG Lan-Min-1, 2 , YU Kai-3, CHEN Tuo-1
    2011, 45 (05):  696-700. 
    Abstract ( 4014 )   Save
    Based on continuous microtremor survey and highdensity microtremor survey respectively at the typical loess areas in the west of China, the time stability and space distribution of microtremor data were studied. The shear wave velocity profile of underground loess layer was obtained using the inversion method of H/V frequency spectrum of microtremor, and contrasting the existing wave velocity data of borehole at this region as well. The results show that the microtremor signal is stable in time range at inland areas of China, and microtremor survey is available and effective for obtaining underground shear wave velocity profile at deep loess sediment ground.
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    Application in Deep Stratum of Soil Investigation Using Long-Period Microtremor
    YU Kai-1, CHE Ai-Lan-1, FENG Shao-Kong-2, 杉Shan-Chang-Zhi-2
    2011, 45 (05):  701-705. 
    Abstract ( 3996 )   Save
    The long period microtremor observation was performed on soft soil area in Shanghai city. The FFT spectrum analysis and H/V method were used to evaluate the spatial variations of long period microtremor and its spectrum stability and clarify the depth of deposits and its horizontal distributions. Comparing the inversion results with the known borehole data, the signal of long period microtremor is good and it is very appropriate to deeply expand the investigations in Shanghai city,the signal of microtrmor in the long period area is steady; the peak of H/V spectrum is obvious and shows regular variation characteristic which reveals the depth of soil in Shanghai city is between 200 m and 300 m.
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    Application of the Method for Seismic Stability of High Rock Slope
    WANG Huan-1, CHE Ai-Lan-1, GE Xiu-Run-1, CHEN Fu-Hai-2
    2011, 45 (05):  706-710. 
    Abstract ( 3894 )   Save
     A high rock slope, which is beside a stonepit at the foot of Tianma hill in Shanghai, is taken as the research object. Surrounding the issue of dynamic stability of high rock slope in engineering and according to the results of laboratory and field tests, the interior factors influencing the stability of high rock slope were discussed, such as geological structure and site condition. Based on this, dynamic finite element method (FEM) analysis for the response of high rock slope under the earthquake will help to confirm the relationship between seismic load and the stability for slope. Combining dynamic FEM with shear strength reduction the dynamic integrity stability for the slope was studied. The results show that the horizontal thrust created by seismic load has significant impact on the stability for slope, which will make rock mass on the top be in danger of toppling into the pit. Meanwhile, the global safety factor and dynamic instability of the slope can be established by mutational displacement method.
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    3-D Modelling of Irregular Shape Particles for Discrete Element Method Based on X-ray Tomography
    DU Xin, ZENG Ya-Wu, GAO Rui, YAN Jing
    2011, 45 (05):  711-715. 
    Abstract ( 4383 )   Save
    In order to build 3-D models of irregular shape particles for discrete element method, the real ballast was scanned with X-ray tomography and its tomography images were obtained, a binary image processing was implemented for each image, and with the method of edgepoints detection, the three dimensional coordinates of the ballast were collected. Then, three governing parameters: minimum radius of basicspheres, efficient space factor, and splitradius were introduced and the generating program of particle was compiled based on VC++. The program combines the basicspheres automatically under an overlap-able algorithm to build the model of irregular shape particles. The research results indicate that with the same preset parameters, the process of modelling can be repeated, and the program is not related to the initial conditions. Meanwhile, the balance of model accuracy and required ball number can be achieved by adjusting governing parameters.
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     Characteristics of Vibration Response of Typical Structure Embankments at Permafrost Regions Along the Qinghai-Tibet Railroad
    WU Zhi-Jian-1, 2 , CHEN Tuo-1, MA Wei-3, WANG Lan-Min-1, 2
    2011, 45 (05):  716-721. 
    Abstract ( 3920 )   Save
    Different kinds of embankments are employed at permafrost regions along the Qinghai-Tibet Railroad. In order to obtain their dynamic response characteristics of typical structure embankments under the effect of train vibration loading at permafrost regions, strong motion observation tests were carried out, at warm and cold seasons of the Qinghai-Tibet plateau, at crushed rock embankment and plain fill embankment at the Beilu River segment. Based on these tests in situ, the dynamic finite element analysis method of two dimensions linearly equivalent was applied for dynamic response numerical calculation on these two embankments. The results show that there is an obvious damping effect during the transfer process from road shoulder to slope toe, the value of vibration attenuation in warm season is greater than that in cold season. And the vibration attenuation in crushed rock embankment is greater than that in plain fill embankment at center roadbed where natural ground locates.
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    Modeling Hydraulic Failure Process Using Elasto-Plastic Cellular Automaton
    PAN Peng-Zhi-1, FENG Xia-Ting-1, WU Hong-Xiao-2, SUN Feng-1, ZHOU Hui-1
    2011, 45 (05):  722-727. 
    Abstract ( 3793 )   Save
    A self-developed numerical tool, i.e. an elasto-plastic cellular automaton (EPCA) was used to simulate the hydraulic fracturing process of rocks. The modeling method of hydraulic fracturing process of heterogeneous rocks with cellular automaton was developed. With the increase of fluid load, fluid will go into the new cracks. The new fluid seepage boundaries will be formed and the tensile stress induced by fluid will be applied on the crack boundaries. In this process, the mechanical properties and boundary conditions will be updated dynamically. The cellular automaton, which is based on the localization theory, makes this operation more conveniently. With this method, the failure process of wellbore rock specimen under hydraulic pressure was simulated, by considering different heterogeneity and different inner radius of the wellbore. It is concluded that, in hydraulic fracturing process, the critical fluid pressure, crack propagation and final failure patterns etc. are greatly influenced by the heterogeneity of the rock, the boundary geometry etc.
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    Characteristics of 1D Compression Residual Deformation of  Saturated Sands under High-frequency Vibration
    LIN Qi, SONG Chun-Yu, ZHENG Wen-Yan, CHEN Long-Zhu
    2011, 45 (05):  728-732. 
    Abstract ( 3650 )   Save
    The saturated sands compression tests were carried out in the lab to study the deformation behavior by 1D compression test system of high-frequency vibration. The effects of vibration time, amplitude of dynamic stress and relative density on the relationship between residual deformation and vibration frequency were investigated. The experimental results show that the plastic residual deformation of saturated sands decreases with the increasing of vibration frequency under high-frequency vibration, and the relationship of logarithmic residual deformation and vibration frequency is approximately linear. The changing values of residual deformation are caused by vibration time, amplitude of dynamic stress and relative density, but the relationship between residual deformation and vibration frequency wouldn’t change. Under the same conditions, the plastic residual deformation of saturated sands is greater than dry sands’.
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    Analysis on Discontinuities Connection Basing on Borehole Photography Method
    GUO Qiang-1, 2 , GE Xiu-Run-1, 3 , CHE Ai-Lan-1
    2011, 45 (05):  733-737. 
    Abstract ( 3380 )   Save
    This paper extended the photography technique to multi-hole occasion and proposed the connection evidences from aspects of orientation and geological characteristics. It also applied the method to foundation investigation of Longjiang Super-major Bridge to test its reliability. It chose three boreholes on the same side of the bridge, on the basis of analyzing and calculating the parameters including spatial position, geological characteristic, orientation and width of the discontinuities. It then contrasted and screened the discontinuities according to connectivity principle, and finally got three discontinuities between two boreholes and two discontinuities among three boreholes. The discontinuities that could be connected own the similar orientations and their spatial positions meet the requirements of lying in the same plane. In addition, the rocks that formed or around the discontinuities own the similar characteristic. The results indicate that it is practicable to apply discontinuity connection method to the engineering.
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    Stochastic Temperature Field of Frozen Soil Roadbed Based on MonteCarlo Method
    SUN Hong-1, NIU Fu-Jun-2, CHEN Zhe-1, GE Xiu-Run-1
    2011, 45 (05):  738-742. 
    Abstract ( 3940 )   Save
    Because of uncertain thermal parameters, the stochastic temperature field of frozen soil roadbed can be correctly analyzed using the stochastic finite element method. Statistical characteristics of geotechnial thermal parameters were analyzed along the Qinghai-Tibet railway, and then random temperature fields of a typical frozen soil roadbed were calculated by the finite element method based on Monte-Carlo method. The results show that the distribution patterns of average temperature fields are similar to that of the standard deviation, and the bigger values are on the scope of top and slope surface of roadbed. The standard deviation, which is the biggest in the boundary, becomes smaller from the boundary to interior, and comes to more uniform at some depth. The standard deviations increase and its distribution scopes enlarge with the time.
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    Acoustic Emission Characteristics of Limestone during Compression and Fracture after High Temperature
    WANG De-Yong-1, WU Gang-2, 3 , GE Xiu-Run-1
    2011, 45 (05):  743-748. 
    Abstract ( 4401 )   Save
    The mechanical properties and acoustic emission evolution process of limestone under the action of high temperature load were investigated by combining the methods of acoustic emission technique and uniaxial compression test. The temperature varies in the range of 100,200,400,600 and 800 °C. Acoustic emission characteristic parameters and the mechanical parameter under different temperatures were analyzed. The results show that the temperature affects the acoustic emission phenomenon of limestone obviously, the peak stress decreases as the temperature increases and drops by 50 percent from 600 °C to 800 °C, but the peak strain changes not obviously; the average accumulative ring-down count increases as the temperature increases before 400 °C but reduces unceasingly as the temperature increases after 400 °C; the specimens present obvious plastic failure characteristic after 600 °C, the accumulative ringdown counts decrease obviously and conform to the stress-strain curve.
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    Vibration Characteristics of Jinshan Existing Railway Subgrade
    XU Jie-1, WANG Feng-2, XIANG Bao-Yu-2, ZHANG Qi-2, WANG Yi-Dong-1
    2011, 45 (05):  749-752. 
    Abstract ( 4749 )   Save
     The field research was made on the test of vibration response of key positions in Shanghai Jinshan existing railway in the case of passing of trains .It is pointed that, the peak vertical acceleration on the surface of subgrade bed in the zone of common subgrade varies from 95.1 cm/s2 to 110.4 cm/s2, and the peak transversal acceleration varies from 89.8 cm/s2 to 116.4 cm/s2. The response frequency of vibration of subgrade bed is focused between 30 Hz and 50 Hz. The vibration energy is left about 30 percent when it arrives at the foundation, and then it will make the vibration level of shallow foundation soils increase. Within 20 meters in the zone of bridge-subgrade transition, the vibration quantity of track and subgrade varies significantly in the longitudinal direction and is relatively higher in the middle of transiton zone. The vibration quantity reaches the maximum at the place where the settlement of subgrade in the bridgesubgrade transition is largest.
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    Multipoint Monitoring Model on Road Foundation Settlement  Considering Heaping Pre-compaction Effect
    HUANG Ming-1, LIU Jun-2
    2011, 45 (05):  753-756. 
    Abstract ( 4760 )   Save
     To analyze and forecast road foundation settlement caused by heaping pre-compaction, the relationship between settlement and heaping process were studied according to the hereditycreep theory. Radial basis function (RBF) artificial neural network was used to establish a monitoring model. In the model, the input units aim at heaping settlement and the output units including multipoint settlement are formed based on surveyed settlement insite and heaping recordation. Moreover, a pre-select RBF center method was presented considering heaping settlement character. It works with fuzzy C-means algorithm (FCM) together to decide final centers. Model instance established in above way with monitoring data describes the heaping effect well, and with good training and forecast results.
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    Bearing Capacity Behavior and Failure Modes of H-V Reinforcement Foundation Based on Strength Reduction Finite Element Method
    ZHANG Tao-Tao, ZHANG Meng-Xi, HOU Juan
    2011, 45 (05):  757-761. 
    Abstract ( 3601 )   Save
    Based on finite element strength reduction in the slope stability analysis, the foundation of nonreinforced ground, level reinforced foundation and a new reinforcement (horizontalvertical, referred to as H-V) foundation were multiple simulated by ABAQUS software. The effect of H-V reinforced foundation on foundation bearing capacity was analysed by using safety factor Fs. The development of plastic zone and the final destruction of the failure surface in the increasing process of the foundation of strength reduction coefficient can be obtained by using ABAQUS post-processing functions. The results show that foundation bearing capacity can be greatly improved because of reinforcement H-V, ground failure mode would have some degrees of changes because of H-V reinforcement.
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    Glass Fiber-reinforced Sand Studied by Triaxial Experiments
    LIU Fang, SUN Hong, GE Xiu-Run
    2011, 45 (05):  762-766. 
    Abstract ( 3182 )   Save
    Triaxial tests on the stress-stain relationship and reinforcement effect of glass fiber-reinforced sand were performed. The results show that there are a little effect of the glass fiber on stress-strain relationship at a small strain level (ε1<1%), and stronger effect at the bigger axial strain with the increase of triaxial strain. Under the same confining pressure, the maximum deviator stress becomes bigger and reinforcing effect becomes stronger with the increase of fiber length and quantity. The higher density induces the reinforcing work earlier, the maximum deviator stress goes bigger and reinforcing effect becomes stronger. The bigger the water contents are, the smaller the maximum deviator stress is. The reinforcing works earlier and the maximum deviator stress goes bigger with the increase of the confining pressure, the reinforcing effect goes worse. 
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    Destruction Process Numerical Simulation of Underground Pit Supporting System under Earthquake Action
    WANG Ying-Yi-1, GU Li-Jun-2, HUANG Xing-Chun-1
    2011, 45 (05):  767-771. 
    Abstract ( 3756 )   Save
    Based on the character of typical foundation pit support structure and method in gravel stratum, by establishing reasonable 3-D seismic response analysis numerical simulation, adopting LS-DYNA software, this paper studied the stability, disability mutation process and time-dependence characteristic of foundation pit and continuous concrete wall with steel support under intense earthquake action. The results show that failure happens in very short time; propagation direction of the seismic wave has a great influence on the structure stability, the least favorable angle is 30°-40°.
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    Communication and Transportation
    Moisture Changes and Influencing Factors of  Unsaturated Soil Subgrade under Atmospheric
    LIU Jie, YAO Hai-Lin, HU Meng-Ling, LU Zheng, CHEN Feng-Guang
    2011, 45 (05):  772-776. 
    Abstract ( 4431 )   Save
    Based on the water, steam flow equation and heat diffusion equation, a subgrade model was established and the moistureity change rule of subgrade under the action of the atmosphere was studied. By changing  the atmospheric  phase parameters and the soil characteristics parameters, the unsaturated roadbed moistureity change rule under the influence of different climate environment was studied. The results show that the effect of atmosphere on the unsaturated soil subgrade is significant, and the depth of the  impact range is limited, the subgrade moistureity change caused by solar radiation is  the largest, the relative moistureity is the second largest; and the influence of the permeability coefficient and soil water characteristics of the subgrade itself on the filled soil moistureity change is very large; the higher the initial water content of the filled soil subgrade, and the bigger the evaporation strength, the higher the subgrade dehydrate degree; the rainwater will easier invade the subgrade, and the moistureity of the subgrade will be changed at long time and small rain rainfall pattern.
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    Architechural Science
    Symplectic Method Based Saint-Venant Analytical Solutions  for Shear Lag Theory of Box Girder
    YANG You-Zhen-a, WANG Yan-Chang-b
    2011, 45 (05):  777-781. 
    Abstract ( 3487 )   Save

    The closed polynomial expressions for shear lag coefficient and effective width were given at the condition of Saint-Venant analytical solutions to full-span uniform load on flange slab of box girder. Availability of formula in this paper was demonstrated by comparing results with international norm and measured values.
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    Hydraulic Engineering
    Destruction Characteristic of Seabed Landslide during Earthquake Motion and Its Mechanism 
    XU Wen-Feng-1, CHE Ai-Lan-2, WANG Zhi-3, WANG Huan-2, LIU Chao-2
    2011, 45 (05):  782-786. 
    Abstract ( 3933 )   Save
    According to a variety of survey methods, the status of the seabed slide near the Hujiu terminal in Xiamen city and the topography, stratigraphy, marine hydrodynamics in the surrounding ground and other factors were identified and the sliding mechanism was analyzed. Based on it, the dynamic numerical analytical method were used to discuss the dynamic response of the slide and the factors influencing the stability of slide, the relationship between instability failure and earthquake motions were identified and analyzed by the dynamic finite element method and strength reduction method. As the results, there is obvious negative response phase between the surface soils for it has quite different mechanical characteristics, so that the tensile stress occurs which leads to collapse of seabed slides.
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