bluuebunny/crossref_metadata_2025 huggingface dataset:
Research on Shallow Buried and Large-Span Tunnelling Undercrossing a Highway
Authors: Liu Chun Yang , Li Jian , Tan Zhong Sheng
Published: September 2011

WenXiang tunnel ,one of the tunnels constructed for the ZhengXi Special passenger Railway in china. In this project we have carried out a series of research on optimizing the construction method for shallow and large-span tunnels in loess condition. According to the field monitoring of ground settlement, vault settlement and primary support stress of the tunnel section before tunnelling underneath the LianHuo Highway, the result indicates that soil settlement and primary support stress can not be controlled very well, and current construction program needs to be reformed since it can not meet construction safety requirement. Our synthetical analysis comprises the optimized methods have been used in construction, such as reducing excavation area, increasing excavation steps of pilot tunnel, reserving core soil, closing invert punctually, reinforcing primary support, etc. The security and reliability also has been verified by numerial analysis sofeware FLAC3D. From feedback of field implement and monitoring result, the effect of optimized method is significant; and all of these methods ensured this tough project implemented successfully. These results derived from our research are subject to a ceritain value that could be referred for future analogous project , in terms of controlling soil settlement and protecting surrouding building facilities.
Field Monitoring and Analysis of Envelope Pile in Shijiazhuang Six-Line Tunnel
Authors: Lin Bao Long
Published: September 2011

The length of Shijiazhuang Railway six-line tunnel(Beijing-Shijiazhuang Passenger line) is 4980m, cut and cover excavation method is used widely. The width of pit is 30~52m and the depth is 8.5~22m. In order to use large machine, cable support structure is used. The west side of pit is Beijing-Guangzhou Railway. The nearest distance from pit is only 10.2m. The cable properties will change because of the train vibration. Therefore, the scope of the train vibration, vibration velocity, anchor axial force and horizontal displacement of pile are measured to get the influence of the train vibration, which can provide basic data for design and construction.
Evolutionary Structural Topology Optimization for Cantilever Construction of Continuous Rigid-Frame Bridge
Authors: Zhang Wen Hui , Zhang Yao Ting , Li Guo Qing
Published: September 2011

In this paper, an evolutionary structural optimization (ESO) method based on the Ishai stress and artificial material elements was used to optimize the structure topology of the cantilever construction of an actual continuous rigid-frame bridge with a new fasting structual system. In iteration process, the engineering infeasible solution was dealt with the engineering constraints; the checkboard problem was solved with the filter scheme, which used the average Ishai stress of the elements located inside the filter domain instead of that located at the center; moreover, the local stress concentration problem was also solved with the scheme of gradully decreasing the filter radius. Thus the iteration ran smoothly, then the optimizing results were obtained finally. The final topology model illustrates the feasibility of the fasting structual system, and the proposed methods are effective to the optimization design for the actual bridge.
Technical Research on Monitor of SLMSS Grider Fabrication for the Passengers Dedicated Line
Authors: Yi Jin , He Guo Jing
Published: September 2011

The yanmiao bridges are used in the 32m prestressed concrete simply-supported box girders on the wuhan-guangzhou passengers dedicated line,they are constucted in the mobile form.To ensure the constuction safety and the accurated line,static load test and monitor for the mobile form were did.The result of test and monitor showed that in the state of work the different parts’force of the mobile form is in the elastic range. The entire beam deflection curve linear is reasonable, they provided the test reference for the the setting of the pre-camber and the control of the box girder’s height.
Multi-Parameter Identification of Geomembrane Viscoelastic-Plastic Creep Constitutive Model by Genetic Algorithm
Authors: Wang Guang Yue , Wang Meng
Published: September 2011

Choosing an appropriate geosynthetics creep constitutive model is the key issue of determining its creep performance. In this paper, a creep overlay model with 7 parameters was put forward based on the analyses of current models. Moreover, the identification of this overlay model was realized by taking use of genetic algorithm MATLAB program. This method proved to be workable by practical example, so it provides a new idea for establishing geosynthetics constitutive model. Creep constitutive model has been the core issue in the research on geosynthetics performances. Although the model identification has gained rich achievements in theory, it is still a problem in practical application. In literature [1] the author adopted Laplace transform to prove that overlay model is strongly inclusive and various creep models could be obtained by selecting different parameter values. So the model identification could be transformed to parameters identification, and in fact both could be realized simultaneously. This avoids overdependence on specific model in the process of identification and the subjectivity of engineering calculation in choosing the constitutive model. This paper will combine overlay model and genetic algorithm to identify the geomembrane creep constitutive model.
Large Extrusion Deflection Control Technology for Tunnel in Active Fault Zone
Authors: Zhang Su Min , Zhu Yong Quan , Liu Zhi Chun
Published: September 2011

The Wushaoling tunnel passes the active engineering fault 7(simply called F7 below), where the surrounding rock is broken, mainly composed of fault boulder clay and rubble with very low strength/geostress ratio, resulting in remarkable deflection. Measures have been taken to control the large deflection of the primary support effectively and to ensure safety of the lining structure so that the F7 can be passed as early as possible . Two small-section roundabout drifts for left and right line each, affected less by the high geostress, are excavated in order to continue the construction ahead, to release partial geostress and to conduct experimental study guiding the design &construction of the main tunnels. At the same time, in-situ experiments are carried on against different pattern and parameters of support structure. Based on the above study, the measures are finally determined such as adopting circular multiple-support composite lining, setting deformation joints per segment to absorb the movement of the active fault, adhering the construction principle of “rapid excavation, rapid support, rapid closure and timely lining”, etc. As a result, the large deflection is controlled effectively in subsequent construction and the large-scale active fault rarely encountered domestic and abroad has been passed successively.
Study on the Interface Mechanical Characteristic of Geotechnical Prestressed Anchorage Bolt under Step Loading by Model Test
Authors: Zhang Si Feng , Song Xiu Guang , Li Yan Mei , Yao Kai
Published: September 2011

The development and evolution regularity of the interface shear stress for the inner bond section of geotechnical prestressed anchorage structure is directly related to the ultimate bearing capacity and its long-term durability. By adopting the similar model test and embedding the strain brick at each interfaces of inner bond section, the interface mechanical properties under step loading were systematically studied. Conclusions can be drawn as follows: the interface shear stress along the axial direction of rod is not evenly distributed, and the interface distribution shape at different radial distance from the rod axis also varies. With the gradual increase of external load, the shear stress peak point continues to move into the deep areas, and resulting in the occurrence of gradual damage mode. In the process, the peak value of shear stress also augment gradually. Along radial direction of the rod, the shear stress concentration phenomenon just distributes within a small radius around the rod body. Adopting the two stage linear function to describe the relationship of shear stress and shear displacement at contact surface is suitable.
Effect of Blasting on the Adjacent Underground Tunnels
Authors: Wu Zu Song , Chen Guang Qi , Zen Kouki , Kasama Kiyonobu , Wang Dao Liang
Published: September 2011

The blasting method is regarded as a simple, convenient and economical method for constructing the underground structure, so it is advisable method for many underground structures to construct. But the investigation of the effect of the blasting dynamic load on the vicinal tunnel structure is rare, and the effect of blasting on the vicinal structures cannot be ignored either; sometimes, the effect will cause crack and even collapse in the tunnel liner and surrounding rock. So this paper presented the effect of blasting on the vicinal underground structure in differential cases using the finite element software Midas GTS. The investigation in this paper indicated which case will suffer the more severe effect caused by blast and let us know the vibration principle of the underground structure in differential case, and that will provide the knowledge about the vibration caused by blasting to the design and construction by numerical simulation; additionally, this paper has presented the reinforcement method about inserting the bolt into the surrounding rock to analyze how to resist the effect of the blast load. So from this analysis, it can be noted that the blasting method or the explosive energy will be chosen on the basis of different construction shape, and the reasonable location of the bolt will be adopted in order to reduce the effect of the dynamic on the vicinal tunnel structure.
The Application and Design of Geo-Grid in the High Embankment Engineering in Airport
Authors: Tang Xiao Song , Zheng Ying Ren , Wang Yong Fu
Published: September 2011

With the conduction of west development in China, the constructions of airports in the southwest mountainous areas are being carried out rapidly. Due to the various exteriors limitations, the embankment engineering in airports often exist some problems such as large height and slope ratio. So the stability of high embankment engineering is very essential to the construction and operation of airport. The cost of geo-grid material is very low and the construction is convenient. The embedding and occlusion of soil mass can be realized through its unique grid structure. The practical engineering shows that the stability of high embankment engineering can be solved through laying geo-grid in the filling soil. At the same time, FEM strength reduction can take the interaction between the components of geo-grid and soil into full consideration. As a strict mechanic method, FEM strength reduction can be reasonably and reliably adopted in the stability analysis, design and calculation of reinforced body with geo-grid.
Analysis of Time-Domain Response Characteristics for Transient Electromagnetic in Tunnel Whole-Space
Authors: Wu Zhan Rui , Qi Tai Yue , Li Bin
Published: September 2011

When it was leading prospecting in tunnel by TEM, the induced eddy current field would be produced on both side faces of a tunnel at the instant of disconnection of the excitation current. The receiver coil received the superposition of the eddy current field in the entire surrounding space, which was different from the superposition of eddy current field only with ground half-space. Using ANSYS computer program numerical simulated the propagation characteristic of transient electromagnetic fields in tunnel and compared the results on ground half-space with that in tunnel whole-space. The response curves were drawn by changing the depth of an abnormal body and the eigenfunction was obtained by fitting the curves. The results showed that the propagation in tunnel indicated “water wave effect” other than “smoking ring effect” on ground and the low conductivity body in tunnel changed the time-domain property of eddy current and displayed different curves.
Analysis of Dynamic Responses of Bridge-Subgrade Transition of High-Speed Railway
Authors: Yang Chang Wei , Zhang Jian Jing , Zhu Chuan Bin
Published: September 2011

Referred the vehicle-track coupling dynamics theory [1] and the vertical dynamic analysis models of Bridge-Subgrade transition developed by Zhai [2] ，Wang [3] and others [4]. This article takes account of the interaction between different structural layers in the subgrade system further by using the dynamic ballastless track model and finally establishes a space dynamic numerical model of the vehicle-track-subgrade coupled system. The dynamic response of the coupled system is analyzed when the speed of the train is 350km/h and the transition is filled with graded broken stones mixed with cement of 3%. Results show that the setting forms of Bridge-Subgrade transition have little effect on the dynamic responses, so designers can choose it on account of the practical situation. Due to the location away from abutment about 5m has greater deformation; the stiffness within 5m should be designed alone. Based on the study from vehicle-track dynamics, we suggest that the maximum allowable track deflection angle is 0.9‰ and K30190Mpa within 5m behind the abutment.
Numerical Simulation Research on Earthquake Induced Dynamic Responses of Underground Tunnel
Authors: Gu Shi Tan , Wang Chun Qiu , Xu Chun Zhao , Yu Feng Hai
Published: September 2011

A number of nodes at different strata positions of tunnel roof were selected as research objects, the law between the roof deformation and the speed or acceleration time-history of horizontal and vertical direction were simulated on conditions of inputting earthquake wave at particular lacation of deep tunnel floor. With the gradually increasing distance from tunnel top surface, the “high -low-high” law of peak values were performed in speed time-history and acceleration speed time-history curves. One peak value was overally performed on vertical speed time-history curves, but multiple peak fluctuation was indicated in vertical acceleration time-history, horizontal speed and horizontal accelaration time-history curves.
The Research of Seismic Active Earth Pressure with Mode of Translation by Horizontal Slices Analysis Method and Shaking Table Tests
Authors: Ma Hong Sheng , Yang Chang Wei
Published: September 2011

In order to get the seismic active earth pressure with the mode of translation, adopting some related assumptions of the M-O theory, this paper establishes the first-order differential equation of the Seismic active earth pressure by horizontal slices analysis method and gets the solution of the seismic active earth pressure by boundary conditions. This formula can solve the distribution of the seismic active earth pressure is nonlinear along the wall, the point of application of the dynamic active thrust which is the advantage of this formula and announces the decreasing process of the filling’s rupture angle with the increase of the horizontal peak ground acceleration (PGA) , as well. The rationality and validity of the formula is confirmed by the comparison between the results of the shaking table tests and the formula, respectively. If the retaining wall takes place the mode of translation, the point of application of the seismic active thrust ranges between 0.4 and 0.5 times wall’s height at the horizontal seismic peak ground acceleration (PGA)<0.4g.At the same time, the computational accuracy of the dynamic active thrust, their points of application and the angle of rupture increases with the increase of the horizontal peak ground acceleration at the horizontal PGA<1.0g, as the astigmatic of the retaining wall in highly seismic intensity region supplying the valuable reference.
Technology of Safe and Efficient Submarine Deposit Mining
Authors: Duan Bao Fu , Zhang Meng , Li Lei , Li Hong Chun , Wu Hui
Published: September 2011

Submarine mining is unprecedented in China. XinLi Mining area, affiliated to Sanshandao Gold mine, is the first metal mining carrying out submarine mining exploitation in domestic. No occurrence of uniform settlement, cracking and collapse is the key point during the mining exploitation. According to the mining choosing principle and combining the production practice and relevant experience of Sanshandao Gold mine, the representative schemes are put forward. Two representative test stopes of 63# and 71# are chosen. After the comprehensive comparison and analysis, high-drift back-filling method is adopted to research the safety of submarine mining. Industrial test results show that the high-drift back-filling method has the significant advantages of safety mining, low ore dilution and so on. The mining production ability is improved greatly, obtaining remarkable effect and realizing the key points of higher efficiency and lower loss rate of ores.
Dynamic Simulation of Underground Excavation and Support Based on Three-Dimensional Finite Element Method
Authors: Liu Hui Bo , Xiao Ming , Chen Jun Tao
Published: September 2011

It is quite important and complicated to simulate sequential excavation and support process effectively and reasonably in underground engineering. To solve this problem, firstly a numerical equation to calculate excavation release loads is proposed concerned with the numerical format of finite element method. And then, an approach to dynamically simulate the excavation and support construction sequentially is put forward, in adopt of the load distribution. On the basis of the distribution of plastic coefficient of the surrounding rock, the load distribution coefficient is identified. The sequential excavation problem is transformed to simple load operation through the FEM calculation. Finally, a case study is further illustrated and it is proved that the approaches could reasonably simulate the dynamic excavation and support process and the effect of support.
Torsional Dynamic Impedance of Pipe Pile Embedded in Viscoelastic Soil Considering Soil-Pile Interaction
Authors: Feng Shu Zhen , Wu Ji Min , Cui Hai
Published: September 2011

Abstract. Based on the three-dimensional wave theory,the coupled torsion vibration of the end bearing pile embedded in viscoelastic soil is researched by using the separation of variables technique. Calculation formulas of the torsional complex stiffness and admittance of pipe pile embedded in viscoelastic soil are obtained and the influence of shear modulus ratio, viscous damping coefficient ratio and the ratio of inner and outer radius on the torsional complex stiffness and admittance of pipe pile are discussed.Finally, the following conclusions are drawn.(1) Shear modulus ratio of soil inside and outside the pile, viscous damping coefficient ratio and the ratio of inner and outer radius have no effect on dynamic damping of pipe pile. The impact of shear modulus ratio of soil inside and outside the pile and the ratio of inner and outer radius on pipe pile in low frequency range is little. With the increase of frequency, the influence is increasing. Viscous damping coefficient ratio does not cause real stiffness of pipe pile. (2) Shear modulus ratio and the ratio of inner and outer radius have a significant influence on the admittance of pipe pile top.The greater shear modulus ratio and the ratio of inner and outer radius, the amplitude of the speed admittance curve of pipe pile top is larger .
Experiment Study on the Durability of Geotechnical Prestressed Anchorage Structure under Cyclic Loading
Authors: Zhang Si Feng , Song Xiu Guang , Li Yan Mei
Published: September 2011

Based on the analysis of the pretension force influence factors for geotechnical prestressed anchorage cables that are used in a practical engineering, the cyclic loading characteristics of prestressed force long-term variation is revealed, and the conception of large and small cycles of prestressed force variety are also put forward. Based on these analysis, a device for the fatigue failure test and the corresponding test methods are manufactured and developed to analyze the durability problem of the inner bond section of prestressed anchorage structure under repetitive loading and cyclic loading. In the experiment, the means of indoor similar model test is adopted, in which the different loading scheme and loading amplitude were taken into account. According to the test results, the fatigue failure regularities of inner bond section for geotechnical prestressed anchorage structure are revealed.
Analysis of Anti-Seismic Fortified Length of Tunnel Portal in High Seismic Intensity Area
Authors: Chen Lin Jie , Liang Bo
Published: September 2011

In high seismic intensity area, strong seismic motion may cause the ruin of highway tunnel, especially the tunnel portal which is the weak links for anti-seismic fortifying. Based on soil-structure interaction model, 3D seismic responses of tunnel portal, in combination with the Menglian tunnel engineering on the Bao-Teng Highway in Yunnan, were performed by using viscous-spring artificial boundary and time history analysis method. The anti-seismic fortified length of tunnel portal to the effects of dynamic and crack property was studied. The results show that the acceleration of lining gradually decreases with the lining extends to the tunnel body under the high-intensity seismic load. Along the axial direction of the tunnel, the crack from the portal 50m is not obvious. The results provide references for the tunnel anti-seismic design．
The Effect of Slide Mass and Pile Stiffness on Residual Thrust on Stabilizing Piles
Authors: Xiao Shi Guo , Tu Wen Bo
Published: September 2011

As for stabilizing piles used to reinforce landslides, landslide thrust acts on their upslope sides but slope resistance acts on their downslope sides at the same time. In fact, the results that the former subtracts the latter are effective loads on piles, which can be called residual thrust on piles. The interaction between pile and rock or soil mass is simulated by elastoplastic finite element method in the paper. And the effect of slide mass and pile stiffness on residual thrust on stabilizing piles is analyzed. The results show that residual thrust on a stabilizing pile become more and more with elastic modulus of slide mass or the pile being increased. Meanwhile, action point of the resultant of residual thrust on the pile is lower and lower with elastic modulus of slide mass being increased but it is higher and higher to some extent with elastic modulus of the pile being increased. These results can be of theoretical reference for comparison and selection of various design plans of stabilizing piles.
The Catastrophe Model Research of Rock Instability of Tunnel Blot-Grouting Support Structure
Authors: Liu Fu Sheng , Zhang Shun Ke , Wang Su Hua , Wang Shao Jie , Song Yang
Published: September 2011

The tunnel excavation destroys rock stress state and when concentrated stress exceeds the strength of surrounding rock, the tunnel periphery rocks will be destroyed. And the effective bearing ring will be soon instable and it needs to be supported. Blot-grouting support is an active support method which organically combines shotcreting support and grouting consolidation and its theoretical research achievements are less. This paper, starting from catastrophe theory, established catastrophe instability model of blot-grouting support body and it also obtained the mechanic judgment criterion of blot-grouting support body damage and the regular pattern of the point (N, q)’s motion tract in the controlling space, of which the influence to the rock stability. And the paper also judged the minimum thickness of blot-grouting support body in the point of catastrophe stability model to provide the basis for theoretical calculation and engineering application.
Study on Soil Improvement of TBM’S Commencement and Arrival in Water-Rich Sand Stratum
Authors: Jiang Hua , Jiang Yu Sheng , Huang Mao Lan , Chen Zhi Qiang
Published: September 2011

In order to keep the safety construction during TBM’S commencement and arrival more and avoid surface settlement and failure accidents happening at the joint areas of TBM’S commencement and arrival, according to mechanical properties and deformation modes of water-rich sand stratum, mechanical and mathematical models are established, and theoretical equations of longitudinal improvement scope based on strength and stability theory are deduced. At the same time, according to geometric structure of TBM and permeability requirement of improved stratum, geometric criterions are proposed. By monitoring and analyzing the whole process of stratum improvement at the joint areas of TBM’S commencement and arrival in line 2 lot 2202 of Shenzhen Metro, longitudinal improvement theory and stratum adaptability of various improvement methods are verified, it provides a reliable theoretical basis for stratum improvement in water-rich sand stratum.
Study on Mechanical Model of Pile Under the Horizontal Axial Load Effect
Authors: Yang Hong Xia
Published: September 2011

According to the operating characteristics of pile which under the horizontal axial load effect,a mechanical model of pile and its surrounding soil interaction with pile shaft under horizontal axial load within elastic semi-infinite foundation was established.Based on the theory of elastic mechanics,mechanics of materials,soil mechanics,etc,solutions to undetermined parameters of mechanical models are deduced.The model in this paper has solid theoretical basis,few parameters,simple determine,and can reflect distributed rule of lateral soil resistance.Through the comparison of static loab test data of the pile foundation and the theoretical calculate value in some project,we know that the actual value and the theoretical calculate value were quite close,this have verified the correctness of the model.The calculation model has certain reference value to determine the horizontal axis bearing capacity of single pile.
The Theory and Stability Studies on Composite Bolted Rock Mass
Authors: Liu Xi Liang , Liu Hong Yu , Han Xian Jun
Published: September 2011

Firstly, This paper applied the basic principle of composite material mechanics, saw the rock mass, anchor, mortar as a kind of composite material, established micromechanics equivalent model of bolted rock mass, deduced corresponding parameters formula of bolted rock mass equivalent mechanical model. Secondly, we analyzed engineering example by using the finite element software, conducted a numerical simulation research on composite model and discrete roadway model based on the theoretical derivation. Finally, we verified the feasibility and applicability of the equivalent method by comparative analysis on two sides and roof-floor displacement of roadway and surrounding stress of rock. Thus, this paper established a simplified equivalent calculation method accord with the stability analysis of bolting and shotcreting support and the overall assess of support parameters.
Research of Affection to the Ground on the Metro Station Driven with Enlarging Shield Tunnels
Authors: Wu Zhan Rui , Qi Tai Yue , Zhong Lin
Published: September 2011

The construction schemes of metro station driven with enlarging shield tunnels based on the shield tunnel in the upper and lower step method of artificial were first used in the dongshankou station of Guangzhou Metro Line VI and applied successfully in practice. This paper analyses and studies comprehensively the affection to the ground on the metro station driven with enlarging shield tunnels through numerical simulation. The study in this paper is mainly considered the ground settlement and movement when enlarging shield tunneling in the left tunnel. The ground settlement and movement up to a certain extent will affect the safety of the above adjacent buildings. This paper will provide some guidance to the application of this construction method in the future.
Application Research of Ground Penetrating Radar Detection on the Metal Structure in Tunnel Lining
Authors: Zhang Bei , Zhong Yan Hui , Guo Cheng Chao , Jin Bo
Published: September 2011

As a nondestructive testing technology, GPR has been become one of the most important tools in quality inspection of tunnel lining at present. It is widely applied to tunnel disease detection, such as the holes, cracks, voids between tunnel lining and surrounding rock, and it is also used to determine the steel arch distribution and lining thickness of tunnel. Through the application of GPR in a highway tunnel lining detection, response characteristics of reinforced bar and steel arch frame are analyzed on radar maps under different frequencies of radar. Through identifying abnormal reflection in radar maps and interpreting its reason, the number and arrangement of reinforced bar and steel arch frame can be obtained. Comparing with the tunnel design, good results are obtained.
Experimental Research on Mechanical Properties of the early-Age Shotcrete
Authors: Xie Nan , Ouyang Jie , Li Bing , Lu Jing Hui
Published: September 2011

Abstract. The compressive strength and elastic modulus of early-age shotcrete have important influence on the safety of tunnel during construction period. In order to investigate the laws of the mechanical properties of early-age shotcrete, experiments on the compressive strength and elastic modulus of early-age shotcrete with two different mixes used frequently on construction sites were carried out. The results show that the compressive strength and elastic modulus of shotcrete develop fairly rapidly and especially the development of elastic modulus of shotcrete is faster than that of ordinary concrete. There is an exponential relationship between the compressive strength and time as well as the elastic modulus development and time. Simultaneously their formulas were derived. The research results of this paper are not only helpful to understand the laws of the mechanical properties of early-age shotcrete, but also provide some reference for the reliability analysis of tunnel under construction.
Seismic Analysis of Typical Cut-and-Cover Subway Stations in Beijing
Authors: Liu Jing Bo , Zhao Dong Dong , Wang Wen Hui
Published: September 2011

To obtain the seismic responses of typical subway stations in Beijing, a nonlinear analysis was conducted using a pushover method for seismic analysis and design of underground structures. The analysis mainly focuses on stress in columns and side walls and relative displacement between top and bottom slabs under 3 different levels of PGA (peak ground acceleration). From the analysis, the column shows good ductility due to its high ratio of reinforcement, and it has a good performance under strong motions. Compared with columns, side walls suffer from brittle failure and lose bearing capacity prior to column for its lower ratio of reinforcement. The calculated displacement indicates that the relative displacement between top and bottom slabs is linear proportional to peak ground relative displacement (PGRD). And compared with peak ground acceleration (PGA), PGRD is a more reliable design parameter of ground motion for underground structures. And the typical subway stations in Beijng can withstand the earthquake with design PGA up to 0.2 g.
Study on the Diffusion Properties of Heavy Metal Copper Ion in Silty Clay
Authors: Zhang Zhen Ying , Wu Da Zhi , Cai Qi Mao
Published: September 2011

The silty clay samples from Xiasha zone, Hangzhou city, are put into the reaction tank, which is specially made to investigate the diffusion characteristics of heavy metal copper ion. The silty clay is compacted, and then the solution with concentration of copper sulfate is 1762mg/L are added into one end of the tank. After laid for a time, several soil samples are cut from different positions in the tank, the adsorption contents of copper ion are tested. Experimental results show that the adsorption contents of copper ion in the silty clay decreases with the increase of the diffusion and movement distance. Besides, the relationship between the adsorption contents of copper ion and the diffusion and movement distance can be formulated as an exponential function.
A Theoretical Model for Estimating the Wear of the Disc Cutter
Authors: Li Feng Hua , Cai Zong Xi , Kang Yi Lan
Published: September 2011

In this paper a method for evaluating the slip speed in rolling contact is introduced from the contact mechanics viewpoint. Based on the analysis of the wear factors of the disc cutter, a theoretical model which includes disc cutter structural parameters and boring parameters is proposed to estimate the wear of the disc cutter in normal wear conditions. This theoretical model provides a basis for estimating the wear of the disc cutter and determining the replacing time of the disc cutter.
Design and Application of Formwork Loop Wheel Machine in Complex Structure Double-Arch Tunnel with Large Cross-Section and Longitudinal
Authors: Huang Ming Li , Zhou Yan Jun , Huo Ya Chao
Published: September 2011

For the cut and cover section of "framework + arch” modular structure of Xiamen Airport Road Project. Based on tunnel design section and other construction, technical requirements, we designed a 24.7 meters long and 13.5 meters wide framework loop wheel, with three rows of columns and complex structure and large cross section. In order to prevent to happen bias, two formwork loop wheel machines are symmetrical constructed.For the difference between outer ramp and main line, methods of filling soil and lengthening pillar are used. In order to reduce the load of the roof frame , scaffolding are installed. Obtained through the project monitoring, framework loop wheel machine meets the security requirements, and can improve construction speed and quality.
The Distribution of Shear Stress along the Anchoring Section of Prestressed Bolt
Authors: Zhang Bo , Li Shu Cai , Yang Xue Ying , Zhang Dun Fu , Li Ming Tian
Published: September 2011

In this paper the distribution of shear stress along the anchoring section of prestressed bolt was presented. The distribution of shear stress along the anchoring section of prestressed bolt was analyzed with the plane elastic theory. The analytical solution of shear stress along the anchoring section was deduced. Several cases of shear stresses were analyzed with the analytical solution. The results show that shear stress of prestressed bolt are not uniform distribution along the anchoring section; it is has no relations with the prestress value where the shear stress peak value is; the shear stress is at a certain range along the anchoring section; the shear stress peak value increases with the increase of prestress value;the larger the diameter of the anchoring section is, the less of shear stress peak value is.
Numerical Simulation on Mesoscopic Damage Evolution Mechanism of High-Speed Railway Tunnel Lining Concrete
Authors: Ma Yun Dong , Li Bo , Fan Bin
Published: September 2011

For the high-speed railway tunnel concrete lining, there have been some such initial damages as initial pores or cracks, therefore the initial damages will be expanded gradually under aerodynamic fatigue loads resulting from the high-speed train passing by tunnel, elastic module attenuation laws of concrete was adopted to reflect the effects of fatigue loads on the tunnel lining mesoscopic concrete, taking the second stage of the elastic module attenuation as the main research stage, the mesoscopic damage mechanism and fatigue damage cracks developing-and-changing laws of high-speed railway lining concrete were simulated under the repetitive aerodynamic loads. Study indicates: for the concrete lining with initial damages, under the repeated aerodynamic fatigue loads, the mechanical properties of the tunnel lining concrete will gradually deteriorate to the whole damage of the concrete structure, which will cause serious inference on the durability of the tunnel especially during the middle and later periods of the high-speed railway tunnel serving.
Survey and Analysis of the Regularity of the Surface Crack in the Loess Tunnel of the Special Passenger Line
Authors: Gao Xin Qiang , Zhu Yong Quan , Ye Chao Liang
Published: September 2011

We have done a survey about the surface crack of the loess tunnel of Zheng-xi passenger railway by field survey, geophysical exploration test and pit detection and also have researched the produced regularity of the surface crack of the loess tunnel, especially about in the depth. The result of the survey and the detection indicates that: (1)The surface crack is mostly visible in the shallow area of the loess tunnel entrance. The visible width of the surface is extensive (0.2~200mm) and it is mostly visible in the tunnel, the depth of which is below 60m. The visible or wide cracks mostly appear in the area whose surface settlement is above 80mm. The width of the surface crack of the tunnel, which has a more shallow depth and a larger settlement, is much wider. (2)The effect of the High-density electrical method reflecting the development of the surface crack is obvious. The method of seismic reflection wave and seismic imaging is more accurate than Rayleigh wave in interpreting depth development of the crack. (3)There are two kinds of performance of the surface crack: longitudinal crack that inclines to the inside on both side of the tunnel and circumferential crack perpendicular to the axis of the tunnel. (4)The visible crack depth of the surface crack is limited, which is about 3.0~10m and it always doesn't reach the top of the tunnel. The depth by the geophysical exploration test is much more depth, which is about 10~15m.
Study on Dynamic Response and Blasting Vibration Monitoring of Small-Distance Tunnels
Authors: Zhu Zheng Guo , Sun Ming Lei , Zhu Yong Quan , Sun Xing Liang
Published: September 2011

In accordance with characteristics of super-small-distance tunnels in Nanjing metro, the peak value distribution of vibration velocity for existing tunnel was investigated when cut-hole blasted under the conditions of different surrounding rock Grades, followed by dynamic response rule of super-small-distance tunnels blasting. In addition, monitoring emphasis should be placed on upper bench for right tunnel blasting. Therefore, controlled measures of the small-distance tunnels were obtained during construction. Not only is the result fit for the metro tunnel, but it can be as reference for similar engineering.
A New Estimation Method for Penetration Depth of Displacement Pile Based on a New Type Cone Penetration Test
Authors: Li Zhi Zhong , Tang Lian Sheng , Hu Yong Qiang , Li Zhao Yuan , Lin Pei Yuan
Published: September 2011

It is of significance for pile foundation design and construction to predict the penetration depth accurately of the displacement pile under a fixed pressure. A new type cone penetrometer and corresponding exploration methods are developed through increasing weight of the device, enhancing the strength of probing rod and probe, and embedding a new function on measuring the total penetration resistance. Not only applied appropriately to various strata except for pebble bed, functions such as the total penetration resistance determination, soil layer classification and soil compression modulus and dynamic-static friction ratio calculation are also provided. Data of total penetration resistance, static point resistance and side friction are measured with the new type cone penetrometer, a new coefficient of dynamic-static friction ratio is introduced and employed to calculate the dynamic side friction, a new estimation method, with which the influence of dynamic side friction is take into account, on penetration depth evaluation of the displacement pile is established and proposed subsequently. Validity of the new method is verified by means of case study of pile engineering and the results indicate, for its high accuracy, the method proposed is of practice and theoretical significance, as well as valuable for popularization.
The Field Test Study of Interaction between Structure and Foundation
Authors: Zeng Chang Nv , Zhou Fei , Tian Wen Li
Published: September 2011

The field tests of interaction between structure and foundation were carried out in the present work which was quite different from the traditional divided method. The field experiments were done by using 20 pressure box and 3 inductance magnet rings in each survey hole. Through the tests data the mechanism of the foundation pressure and the distribution of layer settlement were studied. It is shown that there is an ultimate value as to the contribution of upper structure stiffness. The foundation pressure increases with the construction of building. But it will lead to a steady value from some floor to the top. And in the center of the foundation the foundation pressure is the biggest. As to the layer Settlement, the settlement decreases with the increasing of the depth. The Settlement and different settlement of natural foundation is the key to choose the type of their foundations.
Upper Bound Solution of Rationalized Janbu Method
Authors: Wang Jin Hai , Wang Yong , Wang Hong
Published: September 2011

The theoretical defects of conventional Janbu method are systematically analyzed in this study. On the basis of these theoretical analyses, three inequalities are brought up to rationalize the results of inter-slice shear force, the point of inter-slice normal force and the point of normal force on slip line. The new iteration formulas of rationalized Janbu method are deduced and the process of rationalized upper bound solution is given out. The results of the example given in the end show that the rationalized Janbu method can distinctly improve the results’ reasonableness, and can work out the corresponding reasonable thrust line. And the results of rationalized Janbu method under given safety factor can provide relatively reasonable slipping force and slipping moment for reliability design of reinforcing slope.
Investigations of the Difference in Dam Break Modeling Approaches between 1-D and 2-D Hydrodynamic Model
Authors: Jouzdani Anahita , Kabiri-Samani Abdorreza
Published: September 2011

There are different numerical models performed on hydrodynamic behavior of dam break flood in canals and floodplains based on 1D and 2D modeling approaches. In recognition of increasing demand to precise modeling of dam break flood, and due to the limited instructions to choose the best computational model, this article appraises the difference between 1D and 2D modeling of the phenomenon based on the logical comparison of the results. For this purpose the Zayandeh-Rood dam in Iran was used as the case study and MIKE11 and MIKE21 are used for numerical exploration of the problem. The reliability of each approach is assessed and the applicability of each method for exact analyzing the dam break phenomena was demonstrated.
Productive Experiment of Combined Process Treating Sewage of Three Gorges Reservoir Region
Authors: Ma Xiao Xia , Huang Lei , Guo Jing Song
Published: September 2011

To investigate the domestic sewage treatment processes fitting for small mountain towns in Three Gorges Reservoir Region, a demonstration project was built to treat domestic sewage which combined with anaerobic hydrolysis, natural water-dropping aeration and improved artificial soil rapid infiltration and was based on the features of large terrain elevation and many barren ravines. Changes of major pollutants were analyzed in the combined process. The impact of temperature and influent loadings on removal rates of pollutants was investigated. The results showed that, the treatment system had a strong resistance to the influent loadings with good removal rates of pollutants. There was a relationship between temperature and the removal rates of chemical oxygen demand, ammonia and total nitrogen in the system, where the removal rate of total phosphorus was not associated with temperature. There was a clear linear relationship between effluent concentration and influent loadings, effluent concentration increased with influent loadings. There were approximate logarithmic relationships between removal loadings per unit area and influent loadings.
Study on Safe Thickness of Comparatively Intact Rock Ahead of Karst Tunnel Face
Authors: Guo Jia Qi , Ren Lian Wei , Liu Xi Liang
Published: September 2011

Under the effect of water pressure in karst cave before tunnel face, water inrush happens when excavation face enters into the minimal value of safe thickness. Aiming at comparatively intact rock ahead of karst tunnel face, rock wall often appears to be tensile fracture. With some hypotheses, a mechanical model of water inrush for tunnel face instability has been established, furthermore, the analytical expression to calculate safe thickness of rock wall has been given based on the criteria of tension strength through elastical theories. Combined with Maluqing tunnel in Yiwan line, applicability and reliability of formula is discussed.
Development Analysis of I-Longitudinal Crack in the Vault of Underwater Tunnel Secondary Lining
Authors: Wang Wei , Ni Zhao Peng , Chen Dong Zhu , Yin Guang Ming , Ding Peng , Liao Shi Chao
Published: September 2011

In this paper secondary lining of an underwater tunnel which had appeared I-longitudinal crack was taken as study object according to theory of fracture mechanics. Finite Element analysis was carried out to calculate the stress intensity factor at the tip of I-longitudinal crack which located in vault, then to analyze the extended state of crack based on double-K fracture criteria. The computation results indicate that the stress intensity factor at the tip of I-longitudinal cracks which appear within 20 degrees of the vault do not exceed unstable fracture toughness, lining is in stable growth stage and do not occur instable failure. The stress intensity factor at the tip of I-longitudinal cracks appeared in vault is maximum and appeared in both side of vault is minor, the further away from vault the less of stress intensity factor. When water level below the top of tunnel, with the rise of water level the stress intensity factor at the tip of I-longitudinal decrease and the external water pressure has restrain effect to the crack extension. When water level exceed the top of tunnel, with the rise of water level the stress intensity factor at the tip of large depth of crack decrease rapidly until arrive negative value, then increase backward until greater than unstable fracture toughness and cause lining structural local instable failure.
Study on Application of Fuzzy Synthesis Evaluation Method to Expressways Sound Barriers
Authors: Li Yan , Pan Hai Ze
Published: September 2011

Sound barriers are more and more widely used for expressways, however, the already installed sound barriers lack a complete set of evaluation system. In this paper, the fuzzy mathematics theory was adopted to make a comprehensive evaluation of the sound barriers, in which 12 factors influencing sound barriers design were screened to establish an index system for sound barrier evaluation. On this foundation, Huang Luanzuang school along the Dan La expressway in Hebei Province was presented as calculated example for the fuzzy synthesis evaluation method application, which provides a new idea for evaluating sound barriers.