bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of Liquid Water on the Heat Exchange of Control Layer of Cooling Roadbed
Authors: Huang Ming Kui
Published: May 2011

Based on thermodynamics theory and porous medium theory, the migration regularity of liquid water in the control layer of cooling roadbed is analyzed, and the influence of liquid water on the heat exchange between the control layer and the external environment is discussed. On the basis of the research results, the minimum thickness expression for the control layer is established, by which the liquid water could migrate and exchange heat in the control layer. The results indicate that within the regular thickness scope of design, the influence of water on the heat exchange between the control layer and the external environment could be neglected. The results can provide reference to the design and research for the control layer of cooling roadbed in cold regions.
The Finite Element Model of Discontinuous Rock Masses
Authors: Wu Heng Bin , He Ze Ping
Published: May 2011

The traditional limit equilibrium theory could not consider the discontinuous property of rock slope, and the existing research methods for the discontinuous rock mass confined to the Discrete Element Method and Discontinuous Deformation Analysis. Based on the finite element theory, considering the strength reduction of the joint mechanical parameters, the slope stability with one or two sets joints are analyzed in this paper. The results show that, the sliding surface for one set joint slope is close to the joint dip, and the sliding surface for two sets joints slope is close to the control joint dip.
A Simplified Computational Method of Lateral Dynamic Impedance of Single Pile
Authors: Kong De Sen , Men Yan Qing , Wang Li Hua
Published: May 2011

Research of the pile-soil interaction effect is a complicated issue in civil engineering. Using the principle of soil dynamics and structural dynamics, a simplified computational method for computing the lateral dynamic impedance of single pile embedded in layered non-homogeneous subsoil is established based on a certain assumptions. Both non-homogeneity of soil strata and softening effect of soil layer around pile during vibration as well as separation of pile-soil interface are simultaneously taken into account in the proposed computational method. The characteristics of the frequency-dependency of lateral dynamic stiffness and damping of pile are reproduced. It is shown through the comparative study on a numerical example that the numerical results of dynamic impedance of pile computed by the proposed method are relatively rational and can well agree with the computational and experimental results currently available.
Study of “Wave Type” Uneven Settlement and Reinforcing Method of Soft Clay Foundation
Authors: Sun Li Qiang , Yan Shu Wang , He Hong Juan , Xu Yu
Published: May 2011

The deformation is the dominant factor of the quality of the road constructed on the soft soil foundation. Tianjin DongJiang port is located on the hydraulic filled soil foundation which is improved by using vacuum preloading method. Roads in this area often suffer wave type asymmetry settlement, which serious affects the usage of the road and causes damage to both vehicles and human being. It is found that the initial wave asymmetry deformation of the road on very soft soil foundation usually exists and will be developing continuously under the traffic load. The mechanism of the wavy failure of the road is discussed by establishing a mechanical model. The method of using geogrids to reduce the asymmetry deformation is proposed, the reinforce effect is analyzed using finite element method.
The Numerical Solution of the Clay Passive Earth Pressure Based on Circular Combined Surface Method
Authors: Wu Yan Zhi
Published: May 2011

Applying combined surface,the graphical method is used to calculate the passive earth pressure usually. Not only procedure of the graphical method is complicated but also its precision is poor. Based on the principle of the circular combined surface and methods of mathematics and mechanics method ,a formula of passive earth pressure on cohesive soil,which can be applied to the trial calculation by programming procedures,is proposed. The case analysis shows that the calculated results are the same as those calculated by the Coulomb theory under the conditions of the smooth vertical wall back; In the small,there is slight difference between the two; But with the increase of,the calculated results of Coulomb theory are significantly greater than those calculated by the method. Therefore, in a greater external friction anglebetween the wall and the backfill, it should use the method which optimizes the engineering design and reduces project cost.
Study on Stability of Unstable Rock Masses on Right Bank Slope of JinPing I Stage Hydropower Station, Southwestern China
Authors: Huang Da , Zhang Yong Xing , Huang Run Qiu
Published: May 2011

A lot of investigations showed that unstable rock masses (URM) could be classified into four failure modes：whole slide，rock block landslide，whole shear fall，and compress-rip-slide. Unloading cracks forming URM failure boundary don¢t store water usually，so the main loads to cause URM failure in dam region are weight and earthquake force. According to limit equilibrium theory, Authors put forward different calculation method of stability and criterion of stability state class to different failure mode. The corresponding treatments and cure to URM of different scale and stability state are presented, too.
Study on the Mechanical Properties of Discontinuity under Shearing
Authors: Chen Chuan Sheng , Wen Shi Zhi
Published: May 2011

The mechanical properties of discontinuity are different from those of a whole rock. And the shear strength of discontinuity is closely related to its morphological characteristics. The study of the mechanism of failure of jointed rock mass under shear stress is to reveal its mechanical behavior and its mechanism of failure. This paper presents a fundamental research in the mechanical properties of the regular jugged discontinuity under various normal stresses in the shear test. And it describes the mechanical properties of the regular jugged discontinuity under shear stress and their principal regularities. The strength and roughness of discontinuity under shear stress are investigated by the analysis of the data obtained. And this paper study the calculation of shear stiffness of discontinuity and proposed an empirical formula between the slope ratio and roughness coefficient of discontinuity. Also the changing regularity of the parameters of the shear strength of discontinuity under shear stress is investigated, and an empirical formula is developed to evaluate the shear strength of discontinuity in this paper.
The Analyses on Mechanism and Mode of Instability of Loess Slopes under Surface Loading
Authors: Li Rong Jin , Li Rong Jian , Zheng Wen , Fang Juan
Published: May 2011

The contribution of surface load to the stability of loess slope should be properly evaluated in order to meet the engineering demand in loess area. It is essential to analyze the stability of loess soil slope by means of the strength reduction finite element method instead of the slices method commonly used in practice so far. Firstly, some researches on stability of loess slope are reviewed. Then some different cases of the mechanism and mode of instability of a loess slope due to surface load are analyzed in this paper. Numerical results not only indicate that the safety factor of loess slope tends to change with the different distribution of the surface load, but also reveal that the distribution of surface load has important effect on the mode of instability of slope.
Model Test of Roughness’ Influence on Bearing Mechanism in Rock-Socketed Pile
Authors: Wang Yan Qiang , Gao Rui , Zeng Ya Wu
Published: May 2011

The interface roughness between pile and rock in rock-socketed pile can influence its bearing mechanism largely. At present the numerical simulation, which simulates the interface roughness with changing the surface shape or interface friction coefficient, is used to study the interface roughness’ influence on pile’s bearing mechanism. It can reveal the pile bearing mechanism in some degree; however, there are some defects and limitations in simulation because of its assumptions and simplifications. Based on the pile foundation of Tian-xing-zhou Bridge, the model test is conducted to study the interface roughness’ influence on rock-socketed pile bearing mechanism. In the model test, the surface of model piles are made different ranging from smooth to rough, and the bed rock is simulated with mixture of sand and plaster, the rock-soil overlain the bed rock is simulated with silty sand, the pile is simulated with organic glass rod according to similarity principle respectively. The results show that load-settlement curves grow more gently, the ultimate bearing capacity is bigger, the proportion of point resistance is lower, and the shaft resistance is bigger which reaches more than 70% of total loading as the surface of pile is rougher. The conclusions are useful to deciding the length of pile foundation in Tian-xing-zhou Bridge.
Case Study of Long-Term Ground Settlements Induced by Slurry Shield Tunnelling
Authors: Lin Cun Gang , Zhang Zhong Miao , Wu Shi Ming
Published: May 2011

The Qing-chun Road Cross-river Tunnel is the first road tunnel under the Qiantang River in Hangzhou, and it is also the first experiences of slurry shield tunnelling in Hangzhou soft ground. In order to ensure the safety of construction and reduction of environmental impacts while shield tunnelling, a comprehensive monitoring system was carried out during construction, which included ground settlements, displacements and deformations of installed linings and so on. In this paper, the long-term ground settlements induced by slurry shield tunnelling were described in detail, and careful analysis of monitoring ground settlements was made. This case study shows that: 1. The surface transverse consolidation settlements do not follow the Gaussian curve; usually the largest settlements exist above the centerline of the tunnel or nearby, from where settlements descend outwards. Due to consolidation, the surface settlement troughs widen with time.2. Shield tunneling in soft ground, the turning point in settlement-time curves or settlement rate-time curves can be chosen as the time divides the immediate and long-term consolidation settlements.
Travelling Wave Effect Analysis of Long-Span Cable-Stayed Bridge
Authors: Cui Peng Ju , Gao Da Feng
Published: May 2011

The vertical distance is generally greater of long-span cable-stayed bridge, while the velocity of seismic wave propagation is certain, therefore, the incentive suffered of long-span cable-stayed bridge’s pier is not the same time, but there is a certain time interval. Currently in the bridge designs, seismic response analysis is numerically based on coincident earthquake excitation, so that the actual results are different from the results of obtained widely. Based on the analysis of the traveling wave effect to the long-span cable-stayed bridge under the assumption of seismic waves, there are a series results of the bridge control point displacement, the maximum internal force of the earthquake response, and through these results, conclude some effective conclusions.
Evaluation Indexes of Sand Liquefaction Analysed by Rough Set
Authors: Liu Nian Ping , Wang Hong Tu , Yuan Zhi Gang
Published: May 2011

Sand liquefaction is a problem of complex evolution of the disaster, there is no accurate way to judge at present, this study put forward an analytical method to improve and optimize the evaluation system of sand liquefaction based on rough set. The significance of indexes are confirmed by calculating rough dependability between indexes and result for appraisement, the result show that SPT blow count has the greatest impact on the evaluation system, the groundwater level has greater impact, followed by the sand depth, epicenteral distance and duration. The proposed approach overcame the subjectivity of traditional weight determination method, so it is more objective and accurate, and it is reasonable and effective to optimize the evaluation index of sand liquefaction.
Study on Rock Mass Fragment Size Prediction Technology Based on Three-Dimensional Interception Model
Authors: Feng Xing Long , Li De , Wang Li Guan , Wu Dong Xv , Wang De Wen
Published: May 2011

Based on the law of the spatial distribution, using Monte Carlo technology to simulate joint system, and using three-dimensional solid cutting techniques to build a new rock mass fragmentation prediction model of block three-dimensional interception model. Based on consideration in the joint continuity and the mechanical properties of rock mass, the model simulated the spatial distribution of structure planes according to statistical principles, and predicted rock mass fragmentation using structure planes to cut model prototype and ultimately formed a block muster consisting of cutting blocks. Then, according to a new method of the block shape classification, the distribution statistic rule of internal entities rock block, which are cut out by the structure planes, size and shape are studied. The simulation results show that the fragments with equivalent size of more than 1.65 m account for 40 per cent and those more than 1.26 m account for 59.85 per cent of the total fragment volume.
A Practical Elastic Plastic Damage Model for Concrete
Authors: Qi Hu , Li Yun Gui , Lu Xi Lin
Published: May 2011

In this paper, an elastic plastic damage model is presented based on the combined use of elastic plastic constitutive equations along with continuum damage mechanics. A tensile and a compressive damage variable are adopted to describe the different responses of concrete under tension and compression, respectively. The Helmholtz Free Energy is decomposed into hydrostatic stress component and deviatoric stress components. The hydrostatic stress component is neglected and the deviatoric stress component is amended according to stress state, resulting in a more accurate description of the concrete’s response under multi-axial stress state. Finally, through several numerical simulations it is proved that the proposed model has the capability of simulating typical nonlinear performances of concrete material.
The Impact Analysis of Ground Stability Caused by Exploiting Underground Coal
Authors: Liu Shu Xian , Wei Xiao Gang , Liu Shu Hui , Lv Li Ping
Published: May 2011

Disaster caused by exploiting underground coal is due to original mechanical equilibrium of underground rock has been destroyed when underground coal is exploited. And Stress redistribution and stress concentration of wall rock in the goaf happened too. As many complex factors exist such as complex structures of ground, multivariate stope boundary conditions, many stochastic mining factors and so on, it is difficult to evaluate the damage of the geological environment caused the excavation by surrounding underground coal accurately. Besides that, the coexistence of continuous and discontinuous of deformation and failure of wall rock make a strong impact on the ground, and the co-exist of tension, compression and shear failure also pay a great deal contribution to the destroy. Due to the mechanical property and deformation mechanism of goaf are complex , changeable, nonlinear and probabilistic, which changes with in space and time dynamically, it can not be studied analytically by the classical mathematical model and the theory of mechanics computation. Through finite element analysis software ABAQUS, a numerical simulation of the process of underground coal mining have been made. After make a research of the simulation process, it shows the change process of stress environment of wall rock and deformation and failure process of rock mass during the process of coal mining. The numerical simulation of the process can provide theoretical basis and technical support to the protection and reinforcement of laneway the process of coal excavation. Besides that, it also provides a scientific basis and has a great significance to reasonable Excavation and control of mind-out area.
CT Images Analysis of Damage Process in Loess under Triaxial Conditions
Authors: Wang Hui Ni , Ni Wan Kui , Liu Gao Yang
Published: May 2011

Taking the unsaturated loess obtained from YanLiang district Shaanxi province as the research samples. CT images on structural damage evolution of unsaturated loess were obtained according to the results of the CT scanning and the triaxial shear test of the unsaturated loess. The obtained CT images were divided into five groups based on gray levels and treated through supervised classification method. The evolution of void in three layer sections can be clearly observed from the data of supervised classification. It can be seen that due to the existing of many structural defects such as void, microcracks and ginger like rocks in cross-section of the loess sample, the initial damage is large before shearing. With loess sample shear going on, large void is gradually closed and loess sample is compacted without failure surface, only making some adjustments in the internal structure of soil. The possible reason is that the sample has large moisture content, and soil skeleton is easy to creep and hard to form cracks. The general tendency of structure evolution on loess sample under shear process is as follows: the voids closed, the particle condensates dispersed and the particles realigned, the soil consolidated or worked hardening. This work provides a new experimental method for exploring the structural features of the loess under the triaxial shear conditions from the micro-scale.
Formation and Stablity of the Sky Pond Landslide Dam, China
Authors: Song Yan Hui
Published: May 2011

The Sky Pond landslide dam is located in Muchang valley, a branch of the Yellow River branches. From this point it is about 6Km to the mouth of the valley from where the Yellow River flows 0.8Km downwards to the planned Jishi gorge hydropower station. The Sky Pond landslide dam is actually formed by two landslides from both the left and right bank slopes and completely blocks the seasonal river channel. The volume of the landslide dam is about 14 millions m3 with 2.37 millions m3 water stored in the dammed lake under the condition of perennial mean water level. Because (1) the dam body is large in width and thickness; (2) the dammed lake water is small both in volume and weight compared to the landslide dam; (3) recharge to the dammed lake is basically the same as the discharge every year; and (4) there is a natural spillway in the dam body, the landslide dam is present at least 750 years after its formation. Although landslide dams which have existed for several hundreds to thousands of years are generally considered as stable, there are remains which may fail catastrophically. In order to analyze the stability of the Sky Pond landslide dam and provide justification for the future engineering decisions, this paper describes the engineering geological conditions near the landslide dam and the characteristics of the dam body, and a detailed discussion of the formation mechanism of the landslide. Based on engineering geology investigation, a qualitative assessment of the stability of the dam and an analysis of the probability of dam overtopping and piping is carried out. Limit equilibrium analysis has been used to calculate the stability of the dam slope under various operational conditions. Results of the stability analyses indicate that the Sky Pond landslide dam should remain stable and does not present a potential theat to the planned hydropower station.
The Characteristics and Mechanism of Large Scale Landslides between Huangjinping and Detuo in Daduhe River
Authors: Wu Jun Feng , Wang Yun Sheng , Luo Yong Hong
Published: May 2011

Daduhe River is in western Sichuan Basin which is across the Songpan-Ganzi geosynclinal fold system and the Yangtze para-platform. There are some complex geological backgrounds in this region, such as active new tectonic movements, frequent earthquakes and high seismic intensity. Remote sensing interpretation shows that there are lots of large-scale landslides existing between Huangjinping and Detuo in the upper reaches of Daduhe River. It has been shown by the research that the reason why large-scale landslides happened frequently in this region has a close relationship with its special fault structure, landform and strata distribution. Landslides always develop along the concave bank, free face of mountain or the thin mountain ridge and they all have close connection with fault in different degrees. Although the lithology of this section is constituted by ancient Kangding complex, yet the adverse rock mass discontinuity and free face combination lay a foundation for slope’s deformation and progressive failure. The earthquake force, however, is the key factor triggering landslides.
The Analysis of Feasibility and Prospect of the Depth Exploring for Ore-Deposit in ShangPing Tungsten Ore Area of Tie Shan Long
Authors: Gan Zheng Ru
Published: May 2011

ShangPing ore area locates the anti-connected compound part of the east of east west structure-zone in NanLing and the swelling-zone of new china structure. Region structure belongs to the spinal part of the “mountain” structure in PanGuShan. In the mine area, the structure of buckle and bursting engenders very much and the magma activity is frequent. The geology conditions of becoming ore-deposit are advantageous. This text sets out from history, analyses the conditions of becoming ore-deposit, choices advantageous parts and makes authentic geology evaluation and prospect analysis to the prognostic area in order to guide mine designing and mining better.
Study on Critical Drilling Parameters for Auger Drilling
Authors: Tan Song Cheng , Duan Long Chen , Tan Song E , Shi Hao
Published: May 2011

Auger drilling is widely employed in pile foundation engineering and sampling test for geological sciences, and is even considered as one of the idealest methods for space sampling. However, in practice, drilling parameters are usually determined by experience which might cause unnecessary accidents as a result of transportation blocking of chips. To achieve smooth chips transportation, the existed critical speed models are firstly analyzed and summarized in this paper followed by the main introduction of the proposed new model of critical drilling parameters. The influence of rotational speed and vertical feeding rate on the actual trajectory of chips transportation as well as the selection of critical models for different applied drilling fields are subsequently investigated and discussed herein. Analyses indicate that the critical models of overall combined chips and chips divided into inner and outer layer are more reliable, vertical feeding rate and rotational speed should be taken into account simultaneously. The analyses on the actual trajectory of chips transportation are helpful to understand the motion state of chips. To achieve safe and efficient drilling production, suggested drilling parameters should be provided by manufacturers according to the solving models mentioned in this paper and the specific drilling fields.
Study of the Mechanics Behavior of Small Net Distance Half-Open and Half-Hidden Structure Tunnel
Authors: Zeng De Rong , Xiao Xi Zhuang
Published: May 2011

Basing on the tunneling of Jiaowu tunnel, combining with finite element program, the continuous excavation by load steps is simulated through the “activation and passivity” method. The mechanics behavior of the half-open and half-hidden structure tunnel and the characteristic of stress and deformation of surrounding rock supporting system are studied and gained. By comparing the analysis results with in-situ testing data, Analysis shows that the calculation is correct and that tunneling surrounding rock deformation is of predictability.
A Numerical Study on Operation Modes of Mechanical Ventilation in Underground Tunnels and Comparisons with Full-Scale Experiments and Existing Fire Codes in Taiwan
Authors: Fuh Yiin Kuen , Huang Wei Chi
Published: May 2011

Due to land scarcity in greater Taipei area, continuously conversion from existing railroad to underground are performed to increase the land utility at different phases and span many years. In addition, integration issues between several transportation systems such as mass transit and high speed rail are also of great concerns. Fourth phase of Nangkang North Tunnel was completed and in full operation in September, 2008. During the construction period, fire codes in Taiwan for special constructions (e.g. ubnderground stations) are also going through various revisions while internationally, new regulations such as AS 4391 in Australia and NFPA130 in USA have been validated and updated. In order to verify the compliance of fire codes nationally and internationally, full scale experiments have been performed before opening to public service with emphasis on various operation modes of mechanical ventilation. This paper aims to numerically investigate and compare the effectiveness of CFD (Computational Fluid Dynamics) with experimental results. As a matter of fact, full scale experiments are implemented in fire codes in Taiwan for the structures which cannot fully comply with normal installation of fire equipments. While computational power and resources are improving tremendously in the past few years, we focus on the potentials to gain insightful information through numerical simulation and provide a repeatable reference for the engineers, designers and fire fighters as well as managerial levels in government before undertaking any full-scale experiment.
Load Calculation Method of Tunnels with Shallow Buried Depth and Unsymmetrical Pressure in Regions of Weak Fissured Surrounding Rock
Authors: Zuo Chang Qun , Chen Jian Ping , Liu Hui
Published: May 2011

The key problem of supporting structure design is the load calculation in tunnels with shallow buried depth and unsymmetrical pressure in the situation of weak surrounding rock. The results of simplified calculation method recommended by Code for Design of Road Tunnel differ from the practical situations to a certain extent because of the neglect of load calculation range that makes the results less than the practical values, which will bring about potential safety hazard. Based on the calculation method of the Code, modified computational formulas of vertical load of internal and external sides and horizontal load are put forward based on new assumption conditions and load simplified model. The modified formulas were adopted in the calculation of the entrance of Huo-Cheling Mountain Tunnel with unsymmetrical pressure, and the results were compared with those obtained by the method of the Code and numerical simulation. The comparison show that the results of modified formula coincided with those of numerical simulation, while the values calculated by the Code were smaller.
Impact of Double-O-Tube Shield Tunnel Construction on Independent Foundation Frame Building
Authors: Wei Gang , Hong Jie , Lin Zhao , Wei Xin Jiang
Published: May 2011

Due to its better advantages, Double-O-Tube(DOT) shield has been widely applied in shield tunnel construction. But the impact caused by shield tunnel construction on buildings hasn’t been taken seriously. Considering the interaction of building-soil-tunnel, the independent foundation frame building vertical crossed by DOT shield tunnel was simulated by 3D MIDAS/GTS software, and the impact of construction on the building was analyzed. The results show that: during the passage of the shield tunneling through the building, the settlement of the building increased. The settlement was stable and had a little rebound when shield machine already passed the building. The building’s longitudinal displacement was great larger than lateral horizontal displacement. With the increase of driving distance, the first principal stress P1 and maximum shear strain MSmax increased and then were stable. With the increase of L, the first principal stress P1 and maximum shear strain MSmax tended to gradually reduce the security value, and the maximum differential settlement between columns increased first and then decreased. Finally, the safety of the building was assessed comprehensively.
The Study on Mechanical Properties of Karst Tunnel
Authors: Li Bin , Qi Tai Yue
Published: May 2011

Several numerical models were built by FLAC3D to simulate tunnel with karst around spandrel, tunnel with karst around springe, tunnel with karst around inverted arch and tunnel with karst around side wall. The influence of karsts on the deformation of lining and the safety coefficient distribution of surrounding rock after excavation was analyzed. The results from the numerical modeling suggest as follows: karst around spandrel has extremely unfavorable effect on the deformation of lining and the safety of surrounding rock above the vault, karst around side wall also seriously affect the stability of tunnel due to the asymmetry pressure on tunnel caused by karst, consequently, auxiliary measures should be taken to handle these two cases; karst around springe and karst around inverted arch has limited adverse influence on the overall safety of tunnel, backfill measures are enough to handle these two cases.
FEM Research on the Impact of Changsha Subway Construction to Wan Dai Hotel
Authors: Li Zheng Nong , Wu Zhao Yang , Luo Die Feng
Published: May 2011

For the Wuyi Square Station of Changsha Subway is close to Wan Dai Hotel, the construction process is simulated by FEM software Abaqus to research the settlement and distortion of the hotel building in this paper. To simulate the soil layers and diaphragm walls, compared seepage and stress are considered in the three dimensional elastic-plasticity model, in which the building is replaced by uniform load on the ground and horizontal supports are simulated by uniform load or moving distances. The vertical displacement of building foundation has been calculated, and recharging water has been simulated outside the pit. Finally, the control standards of building settlement are proposed to control the construction security of Changsha Metro Line 2.
Three-Dimensional Numerical Analysis on Heading Construction of Metro Station by Drift-PBA Method
Authors: Yuan Yang , Liu Wei Ning , Ding De Yun , Gao Xin Cai , Ma Meng , Jin Hao
Published: May 2011

Drift-PBA method has been widely used in the construction of metro station. Yet the discussion about the excavation sequence of headings was still a controversy. In this paper, three-dimensional numerical simulation of a metro station construction by drift-PBA was conducted by MIDAS/GTS. The heading construction sequence was studied in the environmental impacts due to the construction, and some suggestions were provided for the site. The calculation results indicated that excavating the upper headings previously could effectively control the shapes of settlement troughs and the deformations of pipelines, and diminish the disturbance to the stratum.
The Model Test Study on Frost Heaving and Melting Sedimentation of Subway Tunnel Construction with Manual Level Freezing Method
Authors: Yao Zhi Shu , Cai Hai Bing , Cheng Hua
Published: May 2011

With the aim of solving technical problems existing in the rehabilitation construction of butt-joint sect works with manual level freezing undermining method, under Huangpu River of Shanghai Underground Subway 4# between Nanpu Bridge station and Pudong South Road Station, Group of large-scaled physical model tests had been performed adopting the Manual Level Freezing Undermining Method (MLFM in brief) in constructing double track tunnel. Firstly, the model design and test system integration were made; afterward, through model tests, the paper systematically studied the laws of stratum frost heaving, melting sedimentation rule and stratum displacement variations etc, during the undermining construction of tunnel being frozen. The results indicate: the Maximum displacement of frost heaving measured at the top of freezing wall during up line freezing process was 1.36mm, which is equivalent to actual work quantity of 29.92mm; the strata melting sedimentation displacement during forceful thawing is 54% less than what was during natural thawing, which illuminates that adopting forcing thawing can reduce melting sedimentation of soil blocks.
Study on Construction Technology for Urban Tunnel Closely Passing beneath Existing Building
Authors: Guo Qing Hao
Published: May 2011

The assessment of the interaction between a new tunnel and existing residential or office building is an important issue in urban area. In this study, special protection design for existing structures is introduced based on an actual engineering project of urban tunnel closely passing beneath an existing residential building. Cavern-pile construction method and deep grouting technique with ultra-advanced steel pipe are used in this project to efficiently control the settlement of the stratums on top of tunnel. Additionally, the effect of tunneling on the existing residential building is investigated through finite element calculations. The load condition, deformation and stability of the tunnel elements beneath building are also analyzed. Then, on the basis of calculated results, it is concluded that the new tunnel constructed by cavern-pile method causes small ground settlement, therefore it does not considerably affects the existing building. The safety of resident is guaranteed.
Numerical Analysis of Construction Ventilation of Long Railway Tunnel in Plateau Area
Authors: Lin Bao Long , Jia Xiao Yun
Published: May 2011

Based on the conditions of Guanjiao tunnel, numerical analysis of air flow field is carried out by the finite element software—CFD in this paper. The results show that when the wind speed is 11m/s, the outlet to the face is less than 50m was better; if the speed is 8m/s ~ 4m/s, the distance is less than 40m better. Under the same conditions, the face wind speed of 40m is larger than of 30m. The faster of the speed, the greater of the attenuation along the way. The best distance from duct to the face is suggested according to different wind speed, which can provide a reference for the construction ventilation of the similar projects in the future.
Digital Underground Space and Engineering
Authors: Wang Chang Hong , Zhu He Hua
Published: May 2011

After a comprehensive review on the exploitation of information technology in geotechnical engineering and underground engineering, a concept of digital underground space and engineering (DUSE) is proposed. Research results show that DUSE is an innovative new information platform for the life cycle of underground space and engineering. DUSE is also a digital museum of the underground space and engineering. By employing the concept, the method and the techniques provided in DUSE, a more realistic and transparent underground space and engineering could be built; huge amount of data could be easily managed and effectively visualized. Therefore, useful information of these data can be processed, improving working efficiency and promoting the implementation of intelligent decision about the engineering project. In addition, some research topics that need to be further addressed are also discussed.
An Integrated Manufacturing System with Reconfigurable Multi-Point Forming Technology for Fabrication of Complex Cladding and Facades
Authors: Pham D.T. , Su S.Z. , Li Ming Zhe
Published: May 2011

Currently, there are no efficient, sustainable and adaptive means of producing large compound-curved cladding and facades in constructional and architectural engineering. This paper described a new and cost effective approach to achieving an integrated manufacturing system by employing innovative digitalised multi-point forming technology. The system integrated with CAD/CAM/CAE/CAT software enables rapid and flexible manufacturing functional and aesthetic panels of 3D freeform cladding and facades through die-less forming and fixture-less assembly.
Excavation Method Analysis of Neighborhood Tunnel on Expressway
Authors: Jin Xiao Guang , Zhu Ling , Cui Bing Wei , Shi Bao Tao
Published: May 2011

Neighborhood tunnel is a special structural type with a clear distance between multi-arch tunnel and usual separated tunnel’s minimum required in the tunnel design regulations. The clear distance is small, so the interaction of two tunnels is relatively great, which will greatly influence the stability of surrounding rock especially interlaid rock. Therefore, it is very necessary to seek a safe, convenient and economical excavation method for neighborhood tunnel. Combining with an expressway neighborhood tunnel engineering practice (with clear distance 4.0m, buried depth 30.0m) withⅡ-class surrounding rock and by three-dimension elastic-plastic element numerical simulation, this paper analyzed the surrounding rock destruction approaching degree and deformation characteristics separately according to cheek pilot method, combination method, and up-down bench method of double tunnel. On the basis of the analysis, this text studies advantages, disadvantages and adaptability of each of the three different excavation methods, to provide scientific reference for design and construction of freeway neighborhood tunnel.
3D Simulation of Tunnel Collapse Consolidation and In Situ Monitoring Analysis
Authors: Chen Zhi Min , Zhao De An
Published: May 2011

A shallow buried tunnel was collapsed during construction. According to the actual situation of the tunnel, different collapse consolidation schemes were put forward and corresponding three-dimensional finite difference numerical models were established and analyzed using FLAC3D software. Base on the 3D Simulation results, a collapse consolidation scheme was determined and constructed. The in-situ monitoring results of vault subsidence and convergence displacement were consistent approximately with the 3D Simulation results. The in-situ measured results were in line with the specification’s allowance and show that the consolidation effect of reinforced concrete casing arch and ahead grouting method is good. This could be referenced for similar engineering.
Design and Field Test of Bolt-Mesh-Cable Support of Extraction Drift in Soft Thick Seam with a Large Angle
Authors: Guo Dong Ming , Zhuang Jing Zhao , Zhang Yi , Wang Yan Bin , Yang Ren Shu
Published: May 2011

Considering the poor support results of extraction drift in soft thick seam with a large angle in Dujiacun Mine, and there’s no similar design in such engineering geological conditions. Firstly, determined surrounding rock stability classification of the drift and obtained that roadway surrounding rock of this mine is type. According to the approximate range of this type roadway surrounding rock, selected parameters of bolt support, then using FLAC3Dsoftware simulated support effect of the roadway with different parameters of bolt support, analyzed the extent of the support effect of various parameters. The simulation results show that the optimal program is φ2200mm round steel bolt in the roof andφ2500mm equal strength thread steel in the two sides. Monitoring results of ground pressure displacement of surface, load of bolt and amount of roof separation show that bolt-mesh-cable support is safe and effective.
Study on Tunnel with Subsurface Excavation Method in Urban to Damage Assessment of Underground Pipelines and Protection Decision-Making
Authors: Yuan Chang Feng , Yu Guang Ming , Wang Xu Chun , Zhang Yue Zhen , Guan Xiao Ming
Published: May 2011

Underground construction will inevitably disturb the surrounding rock and soil, thus endanger the safety of underground pipelines nearby. This paper has established the damage assessment of underground pipelines resulting from underground excavation. Based on GIS platform, it also has developed the damage assessment of underground pipelines and protection decision-making system. The extent of the excavation disturbance is determined through the prediction of the sinking value of the overlying soil caused by underground excavation. The stress and strain leading to deformation of the pipeline were analyzed using numerical simulation. The damage assessment for underground pipelines according to both macro and micro aspects was suggested to provide technical support during excavation of underground engineering disaster prevention and mitigation.
Influence Analysis of the Construction of Ground Building to the Underground Shield Tunnel Built Lately
Authors: Yao Yan Ming , Song Shun Long
Published: May 2011

The interval tunnel of Ningbo metro line 2 goes through the site of a car showroom project. By FEM analysis, the internal force of the tunnel is calculated under the ground upper load. From the engineering planning of the two projects, the time interval of the two projects is about six months to twelve months. When the interval tunnel begins to construct, the settlement of the foundation of the showroom is still not finished. By the analysis of consolidation rate of soil, the additional settlement of tunnel caused by the latter settlement of the showroom building is analyzed. And the safety of the tunnel is evaluated according to the analysis.
Study on Multi-Objective Optimization Design Method for SRHSC Beams
Authors: Zheng Shan Suo , Hu Yi , Tao Qing Lin , Li Zhi Qiang , Li Lei
Published: May 2011

According to the thought of engineering optimization and the theory of composite structure design, the minimum of the project cost and the maximum of the diagonal shear capacity are taken as the optimization objectives whose importance can be adjusted by weighting factors and the linear weighted method is used to establish evaluation function which changes multi-objective into single-objective in optimization. Taking the various constraints into consideration and choosing the sensitive design variables, the mathematical model of the multi-objective optimization design for steel reinforced high-strength concrete beams is provided. Based on the optimization thought of the Complex Method, the nonlinear optimization problems are solved by MATLAB program.
Influence of Tunnel Blasting on the Close-Spaced Tunnel
Authors: Ding Yan Ming , Cong Shu Cui , Wang Ren Tao , Li Hao Wei , Wang Hai Liang
Published: May 2011

According to the blasting monitoring of the main tunnel at hidden digging section of Tuandao Second Road exiting ramp in Kiaochow Bay Cross-harbor Tunnel, the paper shows the influence of vibration on the close-spaced main tunnel. Based on the monitoring results of vibration velocity and vibration frequency in the vertical, horizontal radial and tangential direction, we find that the maximum value of vibration velocity in the main tunnel appears in the range of 5-20m in the rear of the ramp corresponding work face. The magnifying effect of the vibration velocity in the rear of the work face is more obvious than the front in the horizontal radial and tangential direction, and the attenuate effect appears in the front in the vertical direction. The attenuate effect of horizontal radial vibration frequency in the main tunnel appears in the rear of ramp work face. The attenuate effect of vertical frequency in the excavated section is more obvious than the unexcavated.
Research on Repeatability of Karst Water Burst Flood and Stability of Long-Hole Grouting in Long and Large Tunnel
Authors: Zhang Xu Dong , Wang Peng
Published: May 2011

The concept of karst water burst flood is first proposed in Maluqing tunnel construction. The paper analyzes repeatability intermittent hysteresis of karst water burst flood. Work out the plan that long-hole grouting based on these characteristics, and evaluat the safety and stability of water stop cement according to Darcy’s law and site actual measurement.
A Method for Determining Second Lining Supporting Opportunity in Soft Rock Tunnel
Authors: Wang Zhong Wen , Fang Jian Qin , Xia Cai Chu , Bian Yue Wei , He Kun
Published: May 2011

The determination criteria and methods are summarized for the reasonable supporting opportunity which is obtained from the numerical calculation of GeoFEM. It is the limit state of surrounding rock when the second lining undertakes 10 percent of load in Ⅳ grade rock(buried depth 121m), and the surrounding rock with burial depth 43meters reaches its limit state when the second lining bears 5 percent of load in Ⅴ grade rock. The reasonable supporting opportunity will be obtained from those two limit states with the criteria.
An Approach to Determine the Stiffness Reduction Factor of Tunnel Lining
Authors: Zhou Hai Ying , Li Li Xin , Chen Ting Guo
Published: May 2011

Based on the segmental joint tests, it was found that the practical range of joint flexural rigidity was in range of 8500-29000kN•m/rad. A simplified method for determining the stiffness reduction factor of tunnel lining() was proposed using results from the segmental joint tests in which some parameters were obtained by calibration against a 3D Numerical analysis. The influence of joint flexural rigidity, soil resistance coefficient, thickness of tunnel lining and tunnel calculation radius on the stiffness reduction factor of tunnel lining was examined. The stiffness reduction factor can be simply expressed as a function of joint flexural rigidity ratio, soil resistance coefficient, thickness of tunnel lining and tunnel calculation radius for the typical tunnel lining.
Study the Design and Analysis of Al-Shuhadah Bridge and Analysis by Using Plaxis Program of Finite Elements
Authors: Aziz Hussein Yousif , Ma Jian Lin
Published: May 2011

This paper is a studying on the Al-Shuhadah Bridge lies in the Muthanna province south of Iraq, including the soil investigation taken from the project and analysis for the designed bridge firstly manually by using equations 1 and 2 according to the data provided, secondly by using three dimensional Plaxis program of finite elements. The settlement calculated by the above two ways is nearly similar and considered reasonable values compared with the allowable settlement according to Skempton and McDonald (1956) limitations for maximum settlement and maximum angular distortion. The bearing capacity of the bridge also calculated by using equation 3 and the value is larger than the applied load due to the effect of truck loading, while the study found that the bridge is not suitable to carry the dynamic loads due to the effect of train action; therefore, this bridge is used for the highway only and can success for this purpose.
The Influence Factors Researching of Percentage of Load-Carrying Capacity Shared by Concrete for Large Section Concrete-Filled Rectangular Steel Tube Column
Authors: Fu Xue Yi , Xu Na , Jiao Hong Wei
Published: May 2011

Through the analysis of the transmission mechanism—distribution beam for large section (side length>800mm) concrete-filled rectangular steel tube column by the theory of elastic foundation beam we can obtain, percentage of load-carrying capacity shared by concreteis related with vertical spring stiffness of the steel tube, rotational spring stiffness of the steel tube, the vertical spring stiffness of the core concreteand stiffness of the distribution beam. Through analysis of the relationship among percentage of load-carrying capacity shared by concreteand the impact factors, we can identify the main factors that affect the percentage of load-carrying capacity shared by concrete, to control the design of the distribution beam.