bluuebunny/crossref_metadata_2025 huggingface dataset:
Finite Element Analysis on Medium-Speed Mill-Foundation Coupled System
Authors: Yang Man Zhi , Peng Zhi Feng , Liu Fang , Peng Yi Liang , Sun Xiao Ling
Published: June 2012

A medium speed mill-foundation coupled finite element model was established using ANSYS. The modal and harmonic responses of medium-speed mill were analyzed. The influence of the number of vibration isolators and the ratio of foundation bedplate to equipment on the vibration of mill was analyzed. The shock absorption measures of medium-speed mills were discussed. To get good vibration isolation effect, the maximum horizontal vibration displacement of medium-speed mill with spring vibration-isolated foundation is suggested as 50 μm, and the ratio of foundation bedplate to equipment as 3.0±0.2.
Analysis of Storey Damage Effect Factors of SRC Frame-RC Core Tube Hybrid Structure under Cyclic Loading
Authors: Zheng Shan Suo , Yang Wei , Tao Qing Lin , Hu Yi
Published: June 2012

Based on the general finite-element software ABAQUS, the FE model of 30-story SRC frame-RC core tube hybrid structure is built up. The maximum story drift angle of the structure under cyclic loading can effectively characterize the changes in storey damage. With the new achievements on damage effect factors, the relation between storey damage and component damage of various types and influence of the main design parameters on the storey damage law are analyzed. It is found that storey damage degree is more serious with the increase of stiffness character value and shear wall depth-thickness ratio, but the effects of both of them are gradually weakened and the change range of it is really small. Research will provide theoretical support on the building of hybrid structure damage model under earthquake excitation.
Exposure Test of FRP-Reinforced Concrete Structure in Temperate Marine Tide Zone
Authors: Chu Ming Jin , Sun Zhi Juan , Cui Hui Chen , Zhang Ke
Published: June 2012

Through exposure test of FRP-reinforced concrete member in littoral test area of temperate marine zone, the durability and constructional measures of FRP-reinforced concrete structure are investigated. The test results show that FRP shell on the surface of FRP-reinforced concrete member is effective in avoiding wave flush, freezing and thawing damage, preventing chloride ion corrosion and improving durability. On the other hand, reliable measures should be taken to protect concrete structures with no FRP shell on the surface. Based on above, the provided reference for evaluation durability of FRP-reinforced concrete structure, and proper constructional measures for FRP-reinforced concrete structure are presented.
Static Behavior Study for Latticed Concrete-Filled Steel Tubular Wind Turbine Tower Joints
Authors: Li Bin , Qiao Ming , Gao Chun Yan
Published: June 2012

Six latticed concrete-filled steel tubular (CFST) wind turbine tower K-shape joints were carried on the static load test, which included the weld intersecting joint and gusset plate joint. The failure mechanism and characteristics on the two kinds of K-shape joints, the deformation development process after joints entered plastic stage and the stress state and distribution of joint intersection area were studied. The results show that the failure mode and mechanical behavior of CFST K-shape joints are greatly different from that of the hollow steel tube K-shape joints because of the existence of core concrete, the failure mode of the weld intersecting joints showed the local buckling of compression web member and that of the gusset plate joints presented as the compression buckling and tension tearing of the gusset plates, while the plastic deformation failure of tower column tube wall in joint area was not appear. It is also shown by test results that the stress distribution of tower column tube wall and gusset plate in joint intersection is extremely non-uniform, individual parts already enter plastic state but some other parts are still in elastic state. According to the failure mode and stress distribution conditions of the two kinds of K-shape joints, some design suggestions are drawn, which can provide reference for the latticed CFST wind turbine tower joints.
The FEM Analysis of Reinforced Concrete Beam-Slab-Column Joints
Authors: Li Zhen Bao , Zhao Pei Zhong , Ma Hua , Song Kun , Wang Chen
Published: June 2012

In this paper, beam ends of beam-slab-column joints installed in reinforced concrete structures are simulated using ABAQUS FEM analysis software. The simulation work is carried out under the monotonic loading. The damage factor in the plastic-damage model is adopted for describing the damage state of concrete. The failure characteristics, the distribution of cracks on the top side of slab are discussed according to the simulation results. The stresses of longitudinal bars in the slab along with different distances between the longitudinal bar and the beam are given. In reliability assessment of the numerical model, the effects of slab thickness and slab reinforcement ratio on flexural behavior of beam-slab cooperative working are conducted further more.
The Effect of Joint Working Mode between Steel Wires on Local Bending Stress of Stay-Cable
Authors: Li Hong , Zheng Gang
Published: June 2012

The paper proposed mechanics analysis model to simulate the working patterns between steel wires creatively, established and optimized the finite element model to analyses the bending stress preferably and analogue simulate the layered-slipping condition intuitively.
Experiment Study on Static Mechanical Behavior of Plain Steel Plate-Light Weight Concrete Hollow Composite Decks
Authors: Yang Yong , Xu Bo Lin , Zeng Su Sheng , Xue Jian Yang
Published: June 2012

Steel plate-light weight concrete hollow composite deck was a type of novel composite deck which composed of steel plate, perforbond ribs connectors (PBL connectors) and light weight concrete and steel pipe. In order to understand the hollow composite decks mechanical performance, Static experiments of five specimens of this hollow composite slabs were conducted, among which two specimens were composed with longitudinal steel pipes and three specimens were composed with transversal steel pipe, with the aim to study the difference of the mechanical behaviors of the composite decks at the two orthogonal directions. Based on the experiment results, the effects of the direction of steel pips and the nominal shear-span of the slabs on the composite decks mechanical performance were especially studied. During the experiment process, the failure modes, strains of concrete and steel plate, cracking type, slippage of interface and the bearing capacity of the decks were studied in detail. From the experimental study, it could be found that there were no slippage between the steel plate and concrete were measured at the composite bridge decks, and the composite bridge decks showed high flexural rigidity, good ductility as well as better bearing capacity with the strength of bottom steel plate and top concrete both fully utilized. Therefore, it could be concluded that this type of composite bridge decks have good advantages at mechanical behaviors.
Study on Static Design Methods of Plain Steel Plate-Light Weight Concrete Hollow Composite Decks
Authors: Yang Yong , An Kang , Zeng Su Sheng , Xue Jian Yang
Published: June 2012

Based on the experiment results of five plain steel plate-light weight concrete hollow deck specimens, the design methods of the composite decks which mainly including the calculation method of the bearing capacity and calculation method of the flexural rigidity were introduced. In the paper, the bearing capacity and flexural rigidity of the composite at two orthogonal directions, which including the direction parallel to the pipes and the direction perpendicular to the pipes, were both introduced. The calculation results of the bearing capacity and middle-span deflection were in good agreement with those of the experimental results, and in the return calculation methods were verified. Therefore, the design methods and calculation methods were useful to the design of this new type composite deck.
Static Strenght of Doubler Plate Reinforced Tubular K-Joints under Bending Load
Authors: Sui Wei Ning , Zhang Xin Long , Li Guo Chang , Bai Xue
Published: June 2012

Abstract: In order to study static strength of doubler plate reinforced circular hollow section (CHS) K-joints, experimental and numerical studies conducted by the authors. The effects of parameters Δ (the ratio between the length of doubler plate and the diameter of the brace) and α (the width of the doubler plate) on CHS K-joints subjected to bending load have been investigated and reported by the authors. It is found that the ultimate strength of a CHS K-joints reinforced with appropriately proportioned doubler plates can be up to 2 ratio to its un-reinforced counterpart. Reasonable geometric parameters of the doubler plate can make the chord, brace and doubler plate work together to bear the external bending load. The width and length parameter of the doubler plate, however, have no effect on the stiffness of the reinforced K-joints.
Finite Element Analysis of Axially Loaded Column Plated Column Base
Authors: Fang Zheng Gang , Hao Ji Ping , Shi Jiao Jiao , Zhong Wei Hui
Published: June 2012

At present, according to Code for Design of Steel Structures（GB50017—2003）,for axially loaded column with plated column base, the column bases are considered as hinged supports, but possess actually remarkable rotational restraint. The effective length of columns can be decreased when the constraint function of plated column base is considered in calculation. The calculation of effective length factor of columns is usually according to the approximate formula which is deduced by the rotational stiffness. Axially loaded column plated column base models were established with the finite element software, the effective length factor of columns was obtained by the method which can avoid calculating rotational stiffness of plated column bases, the influence factors on the rotational restraint of axially loaded column plated column base, such as the base plate thickness, the diameter of anchors, the column section size were also analyzed in this paper.
Effective Stiffness of Rectangular Confined Concrete Columns with Continuous Compound Spiral Hoop
Authors: Li Wei , Jiang Lei , Sun Lin Zhu
Published: June 2012

Existing models appropriate for design applications tend to overestimate the measured effective stiffness and are unacceptably inaccurate, because they generally neglect the influence of anchorage slip on the effective stiffness of the column. A three-component model that explicitly accounts for deformations due to flexure, anchorage-slip, and shear is shown to provide a more accurate estimate of the measured effective stiffness for the database columns. This model is simplified by neglecting small terms and approximating the results of moment-curvature analysis to obtain an accurate and rational effective stiffness model appropriate for design applications. Comparison the measured effective stiffness of reinforced concrete columns from the PEER Structural Performance Database with stiffness calculated following the FEMA 356. The FEMA 356 procedure substantially overestimates the stiffness of columns with low axial loads, in which there can be significant bar slip in the beam-column joints or footings. This model provides practical recommendations for improving estimates of effective stiffness.
A New Method Tracing Load-Deflection Equilibrium Path of a Doubly Nonlinear Truss
Authors: Liu Shu Tang , Long Qi Liang
Published: June 2012

A new method tracing the load-deflection equilibrium path of a truss with doubly nonlinearity is proposed. The total global stiffness matrix equation has been formulated in terms of nodal coordinates, iteration formulations has been written through adopting a single control coordinate, so that an new method tracing the load-deflection equilibrium path has been proposed. Analysis results of Star dome truss and Schwedeler dome truss have shown that the proposed method is stable numerically, quick in convergence, high in degree of accuracy and easy in use. The proposed method can be used for large-scale truss structure.
Parametric Modeling of Six Typical Double Primary Ribs Reticulated Dome
Authors: Lu Xiao Yang , Chao Wang , Chen Shi Ying , Wang Zhi Dan
Published: June 2012

Based on the structure features of double primary ribs reticulated domes, a method for node generation and element connection of six typical double primary ribs reticulated domes was produced in spherical coordinate system. A macro program was designed by using ANSYS Parametric Design Language (APDL). This six typical double primary ribs reticulated dome modeling was realized under given parameters such as span, rise high, double primary ribs thickness, grid number in circular and radial direction. It is proved by several examples that this method is simple, efficient and possible. It can be easily used to analyze the internal force and optimized design in shell structures.
Simplified Calculation Analysis in Parallel Composite Isolation Structures
Authors: Sun Wu , Yuan Ying , Chen Nian He
Published: June 2012

By using the theory of push-over method, the calculation analysis of parallel composite isolation system is simplified. The results show that the composite isolation system has obvious isolation effects compared with the tradition anti-seismic system. By the use of the simplified calculation analysis method, the calculation of the system can be simplified and the design criterion can be determined. It is applicable for the parallel composite isolation system to the engineering application.
Experimental Research on Full-Scale Reinforced Concrete Columns with Strong Confinement under Concentric Compression
Authors: Zhang Wei Jing , Zhang Bing , Li Zhen Bao , Wang Jinjin , Wang Wen Jing
Published: June 2012

To investigate the axial compressive behavior of reinforced concrete columns with strong confinement, a total of five full-scale reinforced concrete columns with stirrup characteristic values in the range 0.22~0.47 and section dimension 600mm×600mm were tested under concentric compression loading. The test results indicated that all specimens failed in a similar way. The longitudinal bars buckled in compression; the peripheral stirrups bowed out and several stirrups fractured; the cover concrete in the mid-height section of specimens spalled seriously; however, the core concrete of specimens was not crushed. The axial compressive bearing capacity and deformation ability of reinforced concrete columns could be improved by strong confinement. When specimens reached the ultimate bearing capacity, the longitudinal reinforcement yielded and provided axial bearing capacity for specimens; the transverse reinforcement reached tensile yield strength and provided effective confinement for the core concrete.
The Numerical Simulation for Wind Pressure on the Roof of Rhombic Plane and Saddle-Shaped Building
Authors: Wang Cai Hua , Wu Jian Feng
Published: June 2012

The existing “structure load code” did not give wind load shape coeeficient of rhombic plane and saddle-shaped roof .On this issue, numerical wind tunnel method has significant advantages such as low cost,fasting,collecting more comprehensive results.Using information of CFD and the software of FLUENT, using RNG - turbulence model, simulating a landform rhombic plane, the paper had numerical simulation of average wind pressure coefficient for rhombic plane and saddle-shaped roof building. It focused the effect on the numerical simulation for bending-span ratio. Finally it provided reference for reasonably determining the average wind pressure coefficient of rhombic plane and saddle-shaped roof building.
Simplified Calculation Model of Analyzing Fiber Plasterboards Filled with Concrete Core Columns with Different Spacings
Authors: Ma Qing Zhen , Jiang Xin Liang , Zhang Bao Kui
Published: June 2012

The simplified calculating model for fiber plasterboards filled with concrete core columns with different spacings was established. The method for calculating the moment-curvature relationship of concrete core column and the force-displacement skeleton curves of shear element was then proposed. The test data of fiber plasterboards filled with concrete core columns with different spacings were analyzed based on this model. The calculated curves agreed well with the experimental ones, which proves that this model has the advantages of clear mechanical conception，simple calculation and relatively good accuracy，and is convenient for calculating integral structure.
A Taylor Series Integration Method with Coupling in Structural Dynamics
Authors: Guo Ze Ying
Published: June 2012

Based on the coupled precise time integration method and basic assumptions of constant average acceleration method in Newmark family, implicit series solution of structural dynamic equation is put forward by introducing the Taylor series expansion. Relevant time step integration formulas were designed. Stability and accuracy of the method were analyzed. Stability analyses show that the coupling implicit method is stable when damping ratio is equal to 0, and is conditionally stable when damping ratio are other values. The results show that the accuracy of the algorithm can be controlled by choosing the number of truncation order of Taylor series expansion and is better than that of traditional scheme with the increase of time step. Number examples are given to demonstrate the validity of the proposed method.
Geometrically Nonlinear Analysis Based on the Simple Truss
Authors: Wi Di , Li Zhi Da
Published: June 2012

In modern architecture the bridge span becomes larger and larger, as well as the structure is more and more flexible and complicated, therefore geometrically nonlinear characteristics seem unprecedentedly significant. In this paper, the comparison of four calculation methods on a simple truss shows the limitations of linear theory and the importance of geometrically nonlinear theory, and then points out that in the complex structures such as the suspension bridge, we must consider the geometrically nonlinear problem.
Investigation on Line-Shape Control Technology
Authors: Yan Guang Cai , Ma Zhao Xia
Published: June 2012

The simulation analysis of the cantilever construction process was carried out with the structure analysis software. This paper provides an overview of the geometric control and the overall computation according to actual criterion, taking into account the effect of temperature, concrete shrinkage and creep, pre-stressed tension and so on. The elevation monitoring was carried out by comparing the calculated values with testing data. The analysis and control of the line shape are good to perfect the construction control technology of the closure section, enhance the closure quality and ensure the smooth of entire line shape and the rationality of the main beam internal force.
FEM Analysis on Seismic Behavior of Hybrid Coupled Wall System with Steel Boundary Elements
Authors: Shi Yun , Su Ming Zhou , Song An Liang
Published: June 2012

A nonlinear 3D solid model of hybrid coupled wall system with steel boundary elements has been founded by using FEM software ABAQUS to study its hysteretic behavior under cyclic loading, which considering the geometric large deformation and materials nonlinearity. To verify the efficiency of the model, two specimens with various coupling ratios of 30% and 45% are analyzed, and the results of analysis are compared with test ones. As the bearing capacities of both agree well in different loading stages, so the FEM model has enough accuracy and could be used to study the seismic behavior of hybrid coupled wall system with steel boundary elements. In addition, the results show that this new system dissipates energy by shear deformation of steel beams along and plastic hinge deformation at the bottom of wall, so it has better seismic performance.
Damage Detection of Simply Supported Beam under Effect of Moving Load by Hilbert-Huang Transform
Authors: Liu Han Bing , Nguyen Huu Hung
Published: June 2012

Hilbert-Huang transform (HHT) is a signal processing technique is relatively strong and effective today, to overcome the limitations of the used techniques have been widely used as traditional Fourier transform or Wavelet transform. Hilbert-Huang transform can handle effectively nonstationary and nonlinear signal. In this paper present how to use the HHT method to detect damage of the beams under the effect of moving load. Location damage is determined by observing changes in the first instantaneous frequency curve (IF1), damage location is the highest peak in the IF curve. This paper briefly described the theoretical basis and then applies through numerical simulation. These numerical simulations are simply supported beams damaged at different locations and with different levels of damage under the effect of the moving velocity case different. The results of numerical simulation shows relative accuracy compared with the theory and practice is assumed.
Exploration of Offshore Oil and Gas Resources Using Thermal Infrared Remote Sensing
Authors: Cai Yu Lin , Song Zhao Jun , Shan Chun Zhi
Published: June 2012

abstract:Remote sensing technology is playing anincreasingly important role in the investigation and exploration of oil and gasresources. Using thermal infrared remote sensing technology to detect offshoreoil and gas resources is one of new methods, but there are many uncertainties. Inthis paper, MODIS data are used to explore oil and gas resources availabilityin the North Yellow Sea Basinthrough extracting the temperature anomaly areas. Result shows that this methodcan be effective in assisting in exploring undersea oil and gas resources.
Analysis on Monitoring Results of Supporting Program in Foundation Pit of Zhengzhou Exhibition Hotel
Authors: Chen Gui Xiang , Xiao Zhao Ran , Shan Ming
Published: June 2012

Abstract. This article compared the two supporting structure programs which were prepared for the foundation pit of Zhengzhou Exhibition Hotel, from the angle of cost, duration, and deformation conditions. The better one was selected for the project. Monitoring results of two important indicators with the security of supporting structure were analyzed; they were deep displacement in supporting structure and displacement of pile top. With the conditions of continuous excavation, this paper also concluded shifty discipline and tendency of the supporting structure, which could provide some references to similar projects.
The Effect of Coal-Mining on the Bottom Floor Stress and Floor Failure Law
Authors: Gao Zhao Ning
Published: June 2012

According to the geology condition of 1028 face in Suntuan Coal Mine of Huaibei Mining Group, evolution law of stress and displacement of water-resisting floor along with working face ad-vancement was studied. The results show that the stress and the displacement of the floor change dynamically , the displacement in the front and back of working face ,and the difference of displacement result from stress concentration before mining ,relief pressure after mining , superpo-sition effect of additive stress caused by the additional stress in stress recovery . The measures to re-duce the coal floor damage were proposed.
Characteristics and Controlling Factors of Cambrian Dolomite Reservoirs in the Northern Tarim Basin
Authors: Wang Xiao Li , Lin Chang Song , Huang Li Li
Published: June 2012

The discoveries of oil in YM32, the fluid oil and abundant secondary porosity in TS1 well provide the exploration of deep dolostone in Tarim basin with important references. The dolomites are characterized by old age, deep burial and complex diagenesis, thickly and extensively distributed in Cambrian stratum. The spaces of the Cambrian dolomite reservoir are composed of three groups: pores, fractures and combinations. And the dissolved pore and hole, the dissolved fracture and the combinations are absolutely in advantage. The paper discussed the main factors controlling the development of the dolomite reservoirs, and proved that the favorable sedimentary facies belts, various corrosions and hydrothermal activities are the key factors to form favorable dolomite reservoirs. Especially, the favorable sedimentary facies belts are the base of good dolomite reservoirs, the syngenetic karst and dolomitisation laid a solid foundation for secondary pore, and the hydrothermal corrosion is the key factor for well developed dolomite reservoirs.
Stability Analysis of Mountain Slope Based on Finite Element and Discrete Element
Authors: Yuan Wei Bin , Ye Cheng Min , Yao Ji , Wang Lie De
Published: June 2012

In recent year, the foundations of the stability analysis of slope were provided by the development of finite element and discrete element method. Using finite element and discrete element method, the stability analysis of three typical slopes of shiwu thorp of Quzhou was carried out. The safety factors of slope profile were obtained. Based on the judgment criterion of slope stability，the slopes stability of shiwu thorp was judged. The results showed that the way to analyze the stability of soil slope is feasible.
Preliminary Study on the Deformation of Yuxi Basin under Gravity Action by Nonlinear Finite Element Simulation
Authors: Li Tie Fei , Chen Xue Liang , Gao Meng Tan
Published: June 2012

Abstract. A secondary development of the ADINA software for Duncan-Chang E-B nonlinear elastic constitutive model was conducted in this paper, and the veracity of calculation results was verified. To contrast linear constitutive model and Duncan-Chang nonlinear constitutive model, the deformation of YuXi basin profile model under gravity action was calculated by both of the constitutive models. The results show that the subsidence in the linear results is about 12% larger than the nonlinear results, and the nonlinear model has advantages in parameter choosing. Meanwhile, a modified model of YuXi basin which depends on the latest data from our recent work in YuXi area was built to compare with the original model, the calculation results show that the changes in the basin basement structure and basin depth have great influence on the distribution and maximums of the deformation results, when the changes in the internal structure and sequence influence relatively little.
Stability of Huangtupo I# Landslide under Three Gorges Reservoir Operation
Authors: Hu Xin Li , Tang Hui Ming , Li Chang Dong , Sun Ren Xian
Published: June 2012

Abstract. During the normal operation of Three Gorges Reservoir, the water level of the reservoir will fluctuate periodically, which will soften and decrease the shear strength of rock soil on the bank, meanwhile decrease the landslide stability. Huangtupo landslide is a typical large and complex landslide in the Three Gorges Reservoir Region, which is consist of four sub-landslides. In particular, the stability of its riverside Huangtupo I# landslide has a great stake. Based on the analysis of engineering geological condition of Huangtupo landslide, the 2D finite element model of Huangtupo I# landslide(The Riverside Slumping mass I#) was established, the proper mechanical parameters was selected. By using the GeoStudio software, according to the reservoir running curve, the simulation on coupling effect of seepage field and stress field was conducted in 7 different modes within the period of one year. The results showed that: ①the reservoir water level fluctuations will affect both the displacement in saturated and un-saturated area of landslide; especially when the water level drawing down sharply; ②the stability coefficient of Huangtupo I# changes with the reservoir water level fluctuations; the minimum stability coefficient occurs 48 days after the water level drawing down and the moment when the water level falls by 11.9m, under that moment the Huangtupo I# is unstable.
Study of Material Characteristics about Lower Cambrian Black Shale in ZhiJin-KaiYang-XiFeng, Guizhou
Authors: Zhang Jie , Yang En Lin , Di Yong Ning , Xie Fei , Yang Guo Feng
Published: June 2012

The high cambrian black rock series of clay under Zhijin, Kaiyang, Xifeng and other areas of Guizhou , are high carbon black shale - clay rocks characterized by containing illite ores[1]. After deep processing, it will be served as illite ores belonging to a useful clay minerals, and the main directions of development and application include filler, new building materials and ceramics. After the activation, potassium can be extracted from illite that is often rich in potassium which can be prepared for potash fertilizer. Carrying out the study of mineral material science of high carbon black clay mineral rock , the aim is developing and using this type of non-metallic mineral. Based on this study, recoverying useful metal elements by exploring the reasonable technical process will be significant to enhance the comprehensive value of the type of deposit and improve its economic efficiency.
Analytical Method of Calculating Slope Stability by Elasticity Theory and Limit Equilibrium Method
Authors: Lu Ai Zhong , Zhang Ning
Published: June 2012

In this paper, the slope before failure is considered as an elastic body subjected to gravity only. With known stress distribution in the slope, stability analysis is carried out by the limit equilibrium method according to the Mohr-Coulomb criterion satisfied by the slip plane. The method proposed in this paper is different from the previous methods, as there is no need to divide the slope into vertical elements or to assume the normal stress distribution on the slip surface. Instead, the solutions are found by directly using the elastic stress solutions in the slope. The equations derived are straightforward and most of them are explicit expressions, which facilitate analyses on the effects of mechanical properties and geometric parameters on the slope stability. This method has clear physical meaning and few assumptions are made.
Effects of Key Stratum Location on Hydraulic Conductivity Fracture Zone
Authors: Yang Cheng , Bai Hai Bo , Rong Hu Ren , Li Hai Long , Wei Xiao Qi
Published: June 2012

The hydraulic conductivity fracture zone is the main channel causing inrush disaster in mine. This paper makes a few analysis on the effect of the location of primary key stratum through the theoretical analysis and numerical simulation. The results show that: (1). When the distance from key stratum to coal seam is about 3 times than the height of coal seam, the hydraulic conductivity fracture zone is higher than normal but the caving zone is lower than normal. When the distance from key stratum to coal seam is about 11 times than the height of coal seam, the hydraulic conductivity fracture zone is lower than normal but the caving zone is higher than normal; (2). The effect of Winkler foundation is obvious when the distance from key stratum to coal seam is 7 times than the height of coal seam, more even but the inverse is not; (3). We can certain whether the key stratum is fractured or not according to the hypothetical rock cohesive force expediently.
Anti-Collapse Drilling Fluids for the Cretaceous Scientific Drilling in Songliao Basin, China: A Case Study
Authors: Cai Ji Hua , Wu Xiao Ming , Gu Sui
Published: June 2012

CCSD-SK1 well was the first Cretaceous scientific drilling well in the world, locating in Songliao basin, Northeast China. It included main well (also called north well) and south well. This paper introduced the anti-collapse drilling fluid technology in main well where the desired continuous coring section was from 164.77 m to 1792.00 m. Continuous technical barriers challenged the intelligence of drilling engineers of this project. First, preserving the wellbore stability was the most critical aspect of continuous core drilling. From top to bottom, the unconsolidated sandstone in the Quaternary super stratum, the water sensitive shale in the Sifangtai group and upper stratum of the Nenjiang group, and the brittle shale of under stratum of the Nenjiang group increased the difficulty of anti-collapse drilling fluid technology. Water invasion into the shale formation often weakens the wellbore and causes problems such as wellbore collapse, shale destabilization and stuck pipe. Fluids should be designed to mitigate these shale problems. Secondly, the openhole strategy imposed the difficulty of maintaining wellbore stability in the second open process (from 245.00 m to the bottom). Finally, the total expense of the well was only one fifth of south well, which was drilled by an oilfield drilling contractor. To overcome these technical challenges, not only different drilling fluid systems such as PAM drilling fluid, DFD-LG-CMC drilling fluid and DFD-NH4HPAN-SAKH drilling fluid were adopted separately, but also technology of feasible viscosity and managed pressure drilling were used. A total of 395 trips had been run in this Cretaceous scientific drilling well and no accidents even dangerous cases occurred. The experience of CCSD-SK1 (main well) explored a successful way of employing economic drilling fluid to preceding similar scientific drilling projects in similar shale formations.
Experimental Study on the Interface Properties of Geotechnical Anchorage Bolt under Cyclic Loading
Authors: Zhang Si Feng , Feng Jian Xiang , Han Rui , Sun Zhi Gang
Published: June 2012

Geotechnical prestressed anchorage structures are widely used in high slope, deep foundation pit, dam and other geotechnical reinforcement engineerings. Under the influence of the outside environment, its pretensioned force is not fixed, but presents a kind of approximate closed cyclic loading mode, under which 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. In the experiment, the means of indoor model test was adopted, in which the different loading scheme and loading amplitude were taken into account and the interfaces mechanical properties of inner bond section for geotechnical prestressed anchorage structures under cyclic loading were studied. According to the test results, the development and evolution regularity of the interface shear strain for the inner bond section is revealed, and the long-term durability of the geotechnical anchorage bolt under cycle loading is put forward.
Research on the Influence of Diffluent Salt Microstructural Variation in the Course of Recrystallization on the Strength of Salty Soil
Authors: Wang Chun Lei , Jiang Chong Xi , Guan Feng Ju
Published: June 2012

Salty soil distributed widely and the engineering characteristic was complicated. The mechanical property had the relationship with spatial arrangement of soil grains, mineral component and occurrence condition of diffluent salt. The soil microstructure was an important factor to engineering characteristics. The influence of diffluent salt recrystallization on soil strength was learned according to the microstructure analysis by using environment scanning electron microscope and additional equipment X-ray energy spectrum (EDX). The influence of microstructure variation on salt soil strength was obtained by direct shear test on the salty soil before and after dehydrating. The results showed that diffluent salt recrystallization affected soil internal structure. The salty soil microstructure character was different before and after dehydrating, which changed the soil- mechanical property of salty soil.
Permeability Coefficients of Dredged Slurries at High Void Ratio
Authors: Xu Gui Zhong , Gao Yu Feng , Ji Feng , Cao Yu Peng
Published: June 2012

According to sediment rates of slurries in initial stages, permeability coefficients of samples applied in this article is obtained. It shows that the permeability coefficients of dredged slurry determined from sedimentation tests are feasible. In bi-logarithm coordinates, permeability coefficients of dredged slurries increase linearly with the increasing of void ratio. Permeability coefficients, however, increase abruptly when slurries change from soil state into fluid state. At last, a model on the relationship between void ratio and permeability coefficients of dredged slurries is obtained.
Delta Front Depositional System Study Based on Seismic Attributes and Well Logging Facies
Authors: Li Xu Tao , Lin Chang Song
Published: June 2012

Along with analysis of logging facies characteristics of drilled wells, isometric strata slicing technique for seismic attribute is applied to interpret the distribution of the depositional systems in the study area. It is understood that Nenjiang3 Formation in Xinbei area of Xinli field consists of water regressive and sand progressive delta front depositional system from bottom to top. Combined with analogue analysis of well logging facies and planar seismic attributes, it is learned that sediments generally came from the north area, and main sedimentary microfacies include underwater distributary channels, river mouth bars, sheet sands body and interdistributary bays of delta front. With isometric slicing for the extraction of seismic attributes and logging operation, the distribution rules for sedimentary systems could analyzed, thereby providing a feasible method that could be referenced by the study on sedimentary system distribution of other areas.
Inversion of Initial Geo-Stress in High and Steep Slope
Authors: Yuan Zhong Fan , Xu Pei Hua , Ye Zhao Rong
Published: June 2012

At present, due to various reasons, cannot do a large number of field measurements, and the measured results often can only reflect the local stress field distribution. What’s more, the measured results has discreteness, it’s difficult to describe the law of the initial stress field distribution in the entire region. This paper combines topographic and geological conditions and the measured in-situ stress value of Jinping I hydropower station dam area, using FLAC3D4.0, select geological section profile of II1 exploration line for reference, to simulate the incised process of the valley. We get the stress field distribution when rock gravity acting alone, and exert horizontal tectonic stress based on the calculate result of gravity field in the VI terrace model. We inversion the distribution of current Valley stress field, and validate the rationality of the design after compare with the measured data. We obtain the features of stress field of current valley. And we also proved that the regional principal compressive stress plays a decisive role in the formation of the current valley stress field.
Earthquake Damage Evaluation of Tunnels
Authors: Lin Jun Qi , Fang Xiao Qing , Liu Jin Long
Published: June 2012

The state of art of tunnel earthquake damages and tunnel earthquake damage mechanism are briefly introduced in this paper. According to tunnel’s traffic function and damage descriptions based on the investigation, tunnel damages are divided into five grades: no damage, minor damage, moderate damage, major damage and collapse, and their corresponding damage index range and characteristic values are defined. The influence of tunnel materials in Kobe earthquake and Chi-Chi earthquake are collected in this paper, and the damage grades are determined based on the performance in the earthquake. After comparative analysis, the seismic intensity, overburden depth, rock classification, distance to faults and the tunnel length are chosen as the seismic damage influence factors. A formula for tunnel seismic damage evaluation is deducted using these factors and the least square method and with the modification of construction time, seismic fortification intensity and portal stability. The damage of four tunnels is evaluated using the derived formula, and the results are the same with that of static and dynamic methods. It shows that the method provided in this paper is effective, reliable.
Analysis of the Frame Structure’s Force due to Subway Excavation with Different Horizontal Distance
Authors: Wu Zhi Qiang , Hu Yong Li , Lei Yan Ping
Published: June 2012

With large-scale construction of subway lines, the influence of subway excavation to the frame structure has been an common problem to be solved. Finite element software was used to create three-dimensional model of the subway with different horizontal distance to the frame structure, and variation of frame structure’s bending moment, axial force, shearing force caused by subway excavation is obtained to analyze. The results will enable engineering staff to have a more comprehensive understanding on this issue, and provide guiding significance for solving similar engineering problems to some extent.
Field Monitoring and Numerical Simulation Study on Mechanical Characteristics of Extra-Long Highway Tunnel
Authors: Li Xun , He Chuan , Xu Guo Wen
Published: June 2012

Taking Motianling tunnel in Chongqing as an engineering background, the monitoring and measurement scheme is proposed for the extra-long tunnel under complex condition, and the field data and the numerical simulation results is analyzed. The results indicates that, the selected cross-section reflect overall state of the Motianling tunnel, and the structure safety monitoring during operation is considered; by tunnel internal and external observation, it is found that the tunnel face in F22 fault zone may not stay stability, because the monitoring information receive feedback timely, and the supporting measures is proper, the surrounding rock stay stability when excavating; for the typical section, the surrounding rock contact pressure is greater than interlayer pressure, primary lining sustains most of the load ,and the secondary lining plays an assistant role as safety reservation; the maximum of anchor axial force and surrounding rock pressure occur at tunnel crown. By monitoring and numerical simulation, the dynamic excavation and design is realized, the Motianling tunnel is achieved safely and successfully at last.
Study on the Effects of Air Temperature Distribution by Flow State inside Cold Region Tunnel
Authors: Liu Jia Xiang , Zhang Xue Fu , Li Guo Hui , Ma Xiao Cheng , Fu Guo Ying
Published: June 2012

Utilizing the basic theory of heat transfer and computational fluid dynamics and considering the coupling influence of air in the channel and tunnel surrounding rock, the paper deduced control equation of hydrokinetics, calculated the formulas and made secondary development program applying UDF language on ANSYS FLUENT as a basis. Based on materials of Fenghuo Mountain tunnel, the paper analysis for coupled problem of heat transfer of surrounding rock and heat convection between air in cold region tunnel and surrounding rock, and comparative analysis of the annual average temperature between the calculation result and the actual observation records in 2004. The results demonstrated: in the laminar flow condition, the annual average temperature of the cross-section of tunnel entrance and exit is the same as or higher than the tunnel inside. In the turbulence fluid condition, the annual average temperature diminishes from entrance to exit, and there exists mutation between the cross-section of entrance and exit and other cross-section. When air flow state is assumed to be laminar inside Fenghuo Mountain tunnel, the calculation result and the actual observation records are the same. Assumed to be turbulent, both of result are different. Therefore, the calculation depend on the actual corresponding air flow state in tunnels in cold regions designs. The paper results will be providing the theory base and reference of design, construction and study of tunnels in cold regions.
The Density Functions of Pore-Size and Particle-Size Distribution Established by Using Fractal Theory and their Applications
Authors: Tao Gao Liang , Hu Qi Zhi , Pan Ming Yang , Hu Xuan
Published: June 2012

Based on the Sierpinski carpet and Menger sponge models, the density functions of pore-size and particle-size distribution are put forward. Using the proposed density functions, expressions of soil porosity and grain mass are obtained. Using the expression of soil porosity, the porosity of soil sample is correctly predicted. The expression of grain mass is used to predict the mass of grains. The results show that the mass predictions of grains of size smaller than 0.002mm are very close to the measure results.
Classification, Causes of Tunnel Frost Damages in Cold Region and Several New Technologies to Prevent them
Authors: Ji Zhe , Lu Kang Cheng , Ma Chao Chao
Published: June 2012

This paper classifies the tunnel frost damages and discusses their causes, especially the causes of lining structural damage for freezing and they are classified into two categories: the outer freezing damage and the inner freezing damage of lining. The analysis shows that the former has a little effect on the structure, but the latter has big threat. For the phenomenon that cracks frequently occur in the tunnel lining of cold regions, some measures to prevent cracks are presented, including reducing adverse constraints in the process of temperature change and preventing large temperature stress. In cold regions, it is unsuitable to adopt back paste-type water-stops to prevent the leakage from lining construction joints, and a good choice is to utilize the buried drainage water-stops. The ring drainage pipes directly connect with the central drainage pipe, and thermal insulating layer with belt shape is set along the ring drainage pipes in some sections where surrounding rock is water-rich and the middle and lower part of the ring drainage pipe are easily frozen. In sections with high potential freezing threat, an anti-freezing plan is offered that electric heating wires are installed behind the lining wall. The test shows that above techniques have good effects in cold region tunnels.
The Analysis of Fu Longping Double-Decked Tunnel with 3D Finite Element
Authors: Niu Ze Lin , Song Zhan Ping
Published: June 2012

The article analyzed the forced state of the surrounding rock and the tunnel lining for Fu longping double-decked tunnel by the Elasto-plastic finite element method. In the analysis, DP’s yield criterion was employed for the elasto-plastic characteristics of materials. It studied the construction method with the theory, and guided the construction for the double-decked tunnel ,too.
Study on the Impact of Stability around Tunnel Surrounding Rock in Construction Program
Authors: Jin Sheng Ji , Shu Zhe , Zhang Da Sheng , Liu Zi Xin
Published: June 2012

In order to analyze the different construction program under the tunnel surrounding rock stress, strain and plastic zone changes, we take water tunnel group of nuclear power plant as basic project and the application of software FLACIS3D numerical simulation.The results show that: During the tunnel excavation and support group process, the different rock tunnel construction program can produce different stress, displacement and plastic zone extended range of distribution and other aspects.To interval-type excavation program,although previously disturbing effect of the excavation of the tunnel construction and tunnel excavation of rock, it can generate less impact on the stability of surrounding rock. For the latter excavation of the tunnel, the tunnel project area affected by the first digging,the stress can be released, the stability of the first excavation of the tunnel effect is also small.Comparing to sequential and parallel program-type excavation program, the use of interval-style group of rock tunnel excavation will help stabilize the body.