bluuebunny/crossref_metadata_2025 huggingface dataset:
Mechanical Simulation Experiment of Coiled Tubing in Wells
Authors: Guan Feng , Ma Wei Guo , Yi Xian Zhong
Published: November 2012

Coiled tubing operating systems have complex underground loading, by related research, we have got the solution about actual depth which the coiled tubing goes into well, and we also have got the solution about the buckling and lock-up of coiled tubing. The reasonable overall experiment scheme is put forward according to the related functional requirements, the appropriate geometric parameters and dynamic parameters of the experimental system is determined, the function module analysis and structural design of the test bench is carried on. The experimental phenomena about buckling and helical buckling lock-up are analyzed, and the conditions of helical buckling lock-up are put forward. This experiment has provided the basis for the analysis of mechanical behavior of coiled tubing in wells.
The Compression Behavior of Contaminated Clay under Coupled Temperature and Chemical Solution
Authors: Lu Hai Jun , Su Bao Zhan , Tao Quan , Guo Yi Lin , Cao Yue , Liu Chao Chao , Zhang Neng Jun
Published: November 2012

The compressibility of contaminated soil was analyzed through the consolidation test. The results show that, with increasing of the acid concentration, the soil compression is increased. The compression of soil contaminated by alkaline is larger than the soil contaminated by acid. The temperature at beginning section plays catalytic effect on soil structural damage, and the amount of compression of the soil is significantly increased with an increase of temperature. When temperature is increased to a certain value, the amount of compression decreases conversely, this may the cohesion between the soil particles is strengthened. However, with the further rise in temperature, the soil structure shows irreversible damage.
The Research of Flood Pattern Completeness in the Thin and Poor Oil Layers of South West II Area
Authors: Wu Xiao Hui , Song Kao Ping , Dong Chi , Zhang Ji Cheng , Deng Jing Fu
Published: November 2012

As line well pattern is the main development technique in the thin and poor oil layers of Daqing Oilfield South West Ⅱ PⅠ group, the layers have been idle and the degree of reserve recovery is far less than the region level. In response to these problems, we analyzed the balanced flood performance of various layers and the remaining oil distribution through numerical simulation technique. It shows that, the main remaining oil type of intended layers is caused by voidage-injection imperfection. Considering the needs of the follow-up infill well pattern and tertiary oil recovery, we decided to keep the well network independent and integrated without disturbing the pattern configuration and main mining object of various sets of well pattern. Finally we confirmed to perforate-adding the first infill wells of intended layers to consummate the water flooding regime. Through analyzing the production target of different well pattern optimization programs relatively, it shows that the best program has regular well pattern and large drilled thickness.
A Stochastic Finite Element Heterogeneous Multiscale Method for Seepage Field in Heterogeneous Ground
Authors: Xia Yan Hua
Published: November 2012

The finite element heterogeneous multiscale method (FEHM) combined with stochastic collocation method (SCM) called SHMFE is applied to studying the seepage field of naturally heterogeneous multiscale subsurface formations. Kinds of stochastic finite element (SFEM) are mainly computational techniques for the class of problems. But those methods do not report the multiscale nature of the properties of subsurface formations. When the random permeability field is heterogeneous in fine scale comparing to study domain, the simulation by the classic SFEM is not a trivial task. The SHMFE can efficiently solve the problems. In the method, Karhunen-Loµeve (KL) decomposition is used to represent the log hydraulic conductivity Y = lnKεin fine scale. The SCM which couples the generalized polynomial chaos is used to make the problem determined, and then the FEHM method is used to solve it. Sparse grid stochastic collocation method is used when KL expansion has many random variables. The numerical examples demonstrate that the SHMFE approach can efficiently simulate the flow in naturally multiscale heterogeneous subsurface formations with relatively lower computational cost comparing with the SFEM methods.
Study on Seepage Properties of Zheng-Gang Large Landslide under Rainfall Condition
Authors: Zhang Yu , Lu Bo , Sun Huai Kun
Published: November 2012

Under influence of heavy rainfall, the Zheng-gang landslide in Gu-Shui hydropower station of China started to have serious deformation. Based on the geological field investigations, the mechanism of rainfall infiltration was qualitatively analyzed previously. The rainfall infiltration reduces shear strength on the slip surface by increasing pore water pressure and the hydrodynamic pressure is generated which increased with the hydraulic gradient and water level, thus resulting in the instability of landslide and increased landslide movement. Secondly, combined with the seepage theory of saturated-unsaturated, quantitative study was carried out on the seepage properties of landslide under rainfall condition. Not only the dynamic sliding mechanism of landslide is revealed, but also the seepage stability was evaluated. The worst stability condition came out 4 days after the rain stopped, and the maximal thickness of perched water up to 6m. The results of stability analysis have agreement with the field observations. Finally, the effective drainage measures were proposed.
Research on Seepage Field of Underground Petroleum Storage Caverns in Fractured Rock Mass
Authors: Zhang Yun Peng , Yu Song , Zhu Wei Shen
Published: November 2012

Underground seepage discharge field in fractured rock mass surrounding storage caverns is analyzed by using discrete element method and stochastic joint-generation method. Meanwhile water pressure distributions in joints are investigated with a series of curtain pressures and compared with no water curtain. In the case without water curtain the groundwater in joints which locate the upper of underground caverns is drained out and water-seal conditions are completely unrealized. When the water curtain pressure is less than a certain value, the joints that have been drained out can not be saturated, and only the water curtain pressure exceeds this certain value, can groundwater seal the storage caverns.
Numerical Research on the Heat Transfer Properties of Pulsating Flow around the Vibrating Tube
Authors: Zheng Xiao Tao , Nie Si Hao , Yu Jiu Yang , Lin Wei , Liu Qian
Published: November 2012

The heat transfer properties of pulsating flow around the tube with simple harmonic vibration were analyzed. The effect of the angle θ between the flow direction and the tube vibrating direction, which changes from 0° to 150°, on heat transfer properties was numerically investigated by the dynamic mesh technology of FLUENT. The results showed that the transient surface heat transfer coefficient decreases with increasing θ when amplitudes of pulsating flow or vibrating tube increase. Comparing with the still tube, the angle between the temperature gradient and the velocity vector is smaller when the tube vibrates along different directions, hence the field synergy performance is better, and the heat transfer performance is more enhanced.
Research on Factors and Model of Water Production of Bottom Water Reservoir
Authors: Zhang Liang , Shi Yi Zuo , Yan Chang Hui , Wu Xiao Xiong , Zhao Pan , Shang Xiao Feng
Published: November 2012

In block one of Tahe oil field, the Triassic Lower Oil Formation sand with a low-amplitude anticline has a characteristic of bottom water reservoir and a uniform oil/water contact, bottom water is energetic, natural water drive, rock and fluid depletion drive. With the continuous development, oilfield has entered high water cut stage, bottom water coning is significant, oil well has rising of the water content and production decline. Summarized influencing factors of water production and water production mode in block one of Tahe oil field. According to water production factors of oil well, we draw four kinds of water production mode: water production mode of tectonic position, water production mode of poor fault-sealing prediction, water production mode of developed into inter-layers, water production mode of high specific inflow segments. Putting forward four kinds of water production mode provide a theoretical basis to control measures for high yield water of later oil well.
The Sediment Group Evaluation Index System of Extra High Water-Cut Stage in Waterflooding Oilfield Reservoir
Authors: Wang Li Jun , Duan Qiang Guo
Published: November 2012

For reserviors which have multiple pay zones, various types and severe heterogeneity, it is China's successful experience of waterflood development to implement layered waterflooding, layered recovery, layered monitoring, and separated layer stimulation and adjustment. So it is worth paying much more attention on how to judge the rationality of layer series division, and only the layer system is reasonably divided can we obtain a higher recovery. In order to make a comprehensive evaluation of the combination of layer series, this paper has screened and analyzed the main indicators affected by the combination of layer series of development applying the principles of multiple correlation analysis, so that we obtain a comprehensive indicator system of layer series combination evaluation, and this system dose play an important role in reasonable layer series division.
Features of Coal Pore & Fracture in Chuandong and their Relationship with Extra-Low Permeability
Authors: Mao Fei , Tang Jian Xin , Peng Jiao Jiao , Li Zhi Qiang
Published: November 2012

The comparative datas from home and abroad indicate that extra-low permeability of coal seam is the basic reason why the gas outbursts obviously demonstrate three features in Chuandong. Further analysis on the microstructure of coal pore and fracture show that, firstly，the quantity of micro pores is much more than that of macro pores; the total volume of the pores is large while the volume of interconnected pores is small. This is helpful to gas storage but going against gas flow. Secondly, fracture density varys with magnification; there are many short fractures but only a few long fractures; all of the fractures are similar in width and in the form of zigzag; the directivity of fracture extension is irregular. Thirdly, fracture fillings are mainly hard inorganic matters. It is put forward that both pressure sensitive effect and water sensitivity effect exist in the coal seam and they are "double-edged swords" to permeability. In order to increase the permeability, it is necessary to change passive exhausting into active driving, remove gas reservoir and provide the passageway for gas dissipation.
The Study of Combined Mining Technology at Thin Coal Seam with Hard Limestone Floor
Authors: Shen Yu San , Zeng Li Jun
Published: November 2012

The mining of thin coal seam with hard limestone floor require that the mating of full mechanized mining equipments must be scientific and rational.It is difficult to advancing when adopting inclined mining or the face meet geological structure. This paper analyzed and solved the main technical matters in the mining of thin coal seam with hard floor,such as fast marching method of inclined mining face ,process parameters optimization of mining face and meeting geological structure etc.
The Research of Liquid Producing Capacity Variation Law in Water Controlled Reservoir
Authors: Fu Cheng , Huang Bin
Published: November 2012

Through relative permeability, we can calculate core water cut ratio, dimensionless fluid productivity index and production index curve. And according to the data provided by the site, we can calculate actual water-cut, dimensionless fluid productivity index and production index curve in demonstration zone. Then we compare with the theoretical curves. By using combination reservoir engineering theory and dynamic production data method, we study the variation law of reservoir liquid producing capacity.
Analysis about Efficiency of Floor Isolation System Consisting of RFPS System and Dish Spring
Authors: Ge Nan , Chen Hai Bin , Yu Chun Yi
Published: November 2012

A theoretical analyzing approach about the compound floor isolation system consisting of RFPS and dish spring is derived. Computation results show that for the proper specifications, the floor isolation system may exhibit good effectiveness in mitigating the acceleration of the unfixed objects or equipments in both horizontal and vertical direction, while the extra displacement could be limited to be in a manageable range. The expected parameters for mitigating the accelerations agree with that for displacements in a partial domain. The specification of a floor isolation system needs low friction coefficient on the slide 0.05<μ<0.1, a reasonable slide radius 0.6<μ<1.0m, a relatively low stiffness coefficient and relatively high damp coefficient of the dish spring.
A Numerical Study on Shock Wave Characteristics for the Underwater Explosion
Authors: Ju Wei , Liu Yi , Ding Jue
Published: November 2012

Underwater explosion is very important for underwater weapons-design technology and research on the damage effect of target structure. In this paper, the flow-out boundary and variable step-size multi-material Euler algorithm were utilized to analyze numerically the whole process of shock wave generation and propagation, as well as bubble formation and impulse of underwater explosion. The computed results reveal the energy output characteristics of underwater explosion by TNT charge, which provide an important scientific basis for formulation design of charge and improvement of damage effects for underwater target.
Bifurcation Analysis in a Lotka-Volterra Model with Delay
Authors: Xu Chang Jin
Published: November 2012

In this paper, a Lotka-Volterra model with time delay is considered. The stability of the equilibrium of the model is investigated and the existence of Hopf bifurcation is proved. Numerical simulations are performed to justify the theoretical results. Finally, main conclusions are included.
Calculation of Interface Slips in SRC Members by Energy Method
Authors: Hu Xiao Hui , Yang Pei Hong
Published: November 2012

Based on the experimental materials, bond–slip behavior of the steel reinforced concrete (SRC) column is studied here. According to the characteristic of the loads, the slip displacements formulation between steel and concrete of a SRC column subjected to push-out load is derived by energy method. The calculation results show that the slip curves have the basic characteristic of quadratic curves distribute.
Stability Analysis of Unstable Rock after Strong Earthquake
Authors: Pan Jian Ping , Tian Jin Hua , Liu Xiang Ping
Published: November 2012

Body size of unstable rock and the impact scope of disasters are simply presented in Duba elementary school in Beichuan county, Sichuan, China. Based on the disaster’s nature, developmental history and characteristics of destruction, the law of disasters such as the movement mechanism, catastrophic failure modes, have been studied. The stability of post-earthquake unstable rock is analyzed and evaluated, and such the disaster prevention principles against unstable rock are advanced.
Semi Analytical Solutions of Elastic-Plastic Contact between Two Surfaces
Authors: Tian Hong Liang
Published: November 2012

A problem related to widespread accepting GW model is that there is no analytical expression for the parameters of interest at the interface. The probability density of asperity heights for closely 90% of engineering surfaces tends to be Gaussian. Taking GW model simple exponential probability density to approximate the Gaussian one is not explicit for some conditions. Many practical closed form analytical expressions were derived for the contact load, contact area and contact spot number for GW elastic contact model.
A Comparative Study of the Methods for Calculation of Journal Bearing Elastohydrodynamic Lubrication
Authors: Zhang Jun Yan , Han Shu Kui , Zhang Su Fen , Zhang You Wei
Published: November 2012

Based on the fast fourier transform（FFT） and flexibility matrix method, the study is presented for journal bearing elastohydrodynamic lubrication. The effects of FFT and flexibility matrix method on the distribution of oil film pressure and elastic deformation in the steady load are investigated. The results are shown that the difficulty of the EHL for journal bearings in the case of high eccentricity ratios or heave loads can be effectively solved by the FFT method. When the eccentricity ratio is smaller, the magnitude and distribution of the oil film pressure are basic agreement by FFT method and flexibility matrix method. When the eccentricity ratio enhances, the maximum oil film pressure obtained by FFT method is bigger on both ends of the journal bearing and on its intermediate is smaller.
Causes Analysis of Eccentric Wear of Sucker Rod in Produced Fluid with Polymer
Authors: Liu Bao Jun , Fan Cai Xia , Du Hong
Published: November 2012

After polymer flooding was put into effect in DaQing oilfield, eccentric wear of sucker rod and tubing has been so serious that it made the rods break. This is because production liquid produced from normal wells is pure viscous fluid while liquid produced from polymer flooding oil wells is viscoelastic fluid. The flow equation of viscoelastic fluid in eccentric annulus was established in cylinder coordinate system, and the velocity distribution was solved. Based on upper-convected Maxwell constitutive equation, the normal stress calculating model of viscoelastic fluid acting on sucker rods was established. The normal stress of viscoelastic fluid acting on inner rod in eccentric annulus was measured under different experimental conditions indoors. The result proves that normal stress is the main reason of eccentric wear.
Analysis of a New Adjustable Mixer Base on Large Eddy Simulation
Authors: Nie Xin , Ding Lin Xiang , Guo Bing , Chen Li Bo , Pan Hua Chen
Published: November 2012

Abstract. This paper presents a new type of adjustable mixing equipment, and the internal flow field of the adjustable mixer have been studied by using the model of LES(Large eddy simulation),and the pressure loss, the speed change and vortex scale have been studied. In conclusion, along with blades angle and number increases, the flow resistance increases violently, so the range of blade rotating angle should be controlled within 30 degrees. As the depth of the pipeline velocity is increasingly large, large velocity gradient is contributed to the collisions between the colloidal particles. In pre-mixed, the vortex effect of the pipeline highly enhances the vortex diffusion, and improves the mixing efficiency. The vortex strength will be reinforced and dimension will be reduced, with the vanes cutting the flow, which can help flocculation.
Study on the Effect of Resistance Sliding Key Chamber Blasting Construction of a Hydropower Station on Adjacent Buildings
Authors: Deng Hua Feng , Luo Qian , Yuan Xian Fan , Zhu Min
Published: November 2012

In order to monitor and control the effect of blasting vibration on dam body, spillway overflow surface and mechanical and electrical equipment foundation at the excavation of resistance sliding key chamber, the fixed monitoring point scheme was used to monitor vibration speed of each point. According to the construction progress, a total of 44 times blasting vibration test were carried on, and data are integrity, which can accurately reflect the effect of resistance sliding key chamber excavation blasting on adjacent buildings. In blasting construction process, according to the analysis of monitoring data, the explosive dosage of single stage was adjusted, which effectively control the effect of blasting vibration. The results indicate that, in the process of resistance sliding key chamber blasting construction, particle vibration velocities of adjacent buildings such as dam body, spillway overflow surface, mechanical and electrical equipment foundation and etc. are in the velocity range of security vibration, which meets the requirements of design and specification, and real-time analysis of field monitoring guarantees the smooth completion of site construction.
Analysis on Impact Factor Spectrum for a Continuous Bridge under Normal Traffic Flow
Authors: Fei Zeng Qian , Wang Tao
Published: November 2012

Analysis was carried out for dynamic responses on a continuous bridge under normal traffic flow. The inspection, testing and analysis for the tested bridge mainly consist of the measurement of pavement roughness and analysis on power spectral density, the testing and analysis on natural vibration characteristics, the observation of traffic loads under normal traffic flow and the corresponding measurements of dynamic displacement and acceleration on bridge. To determine impact factors in terms of measured dynamic displacement responses, low pass Butterworth filter is used for filtering the dynamic part of measured dynamic displacement and the static extreme values are reserved. And then，the distribution fit test is performed using K-S methodology for measured impact factors according to Extreme-I type respectively. Finally, the impact factor of this bridge, which is determined based on statistical method, is compared with code-specified impact factors of different countries.
Application of Improved Gray Correlation Analysis Model to the Estimation of Country Rock Stability
Authors: Lei Jin Sheng , Bao Lei , Wen Liang , Chen Jian Fei
Published: November 2012

The estimation of country rock stability in underground engineering is the important basis for carrying out engineering design and formulating corresponding engineering measures. The interval form of quality standard, the value of resolution coefficient ρ and the weight of correlation degree are seldom takend consideration by the traditional gray correlation analysis model, an improved gray correlation analysis model is used to analyze the five indices of influencing the country rock stability: rock quality designation RQD, moisture compressive strength Rw, integrity coefficient Kv, structure surface strength coefficient Kf, groundwater seepage measurement W/L. The results show that the improved correlation analysis model is superior in its objectivity and applicability as well as certain practical value in evaluating country rock stability or other evaluation problems.
The Structural Refinement and Vibration Analysis of Apparatus Based on Inertia Benchmark for Measuring Road Roughness
Authors: Xue Jin Lu , Wang Hong Yan , Chi Bao Shan
Published: November 2012

The Apparatus for measuring road roughness based on inertia benchmark are usually used with method of “calculation amendment”. The exquisite vibration of sprung mass and double integration of acceleration can bring error to measuring result. The amelioration was took to this kind of device by adding a mass block called measuring benchmark. Vibration characteristic was analyzed through vibration equation. To reduce the error, the perfect combination of system parameters was found to minish the amplitude of measuring benchmark. The analysis indicated that when selecting appropriate system parameters the dimensionless amplitude can be tend to “1”.
Experimental Research on the Heat Transfer Characteristics of Electrorheological Fluid Shock Absorber
Authors: Wang Rui , Wang Yi Chun , Feng Chao Qing , Zhou Fei
Published: November 2012

Abstract：In order to study the thermal conductivity of ER in shock absorber, the AL2O3 and TiO2 ultrafine particles silicone oil ER are prepared to the different weights and been researched by experiment. Experiment result indicated: in the 5 mm scope of the electrode plank, the voltage from zero to three thousand, the thermal conductivity of ER fluids go up linear with the voltage growing, but the range is smaller; from three thousand to four thousand and five hundred voltage, the thermal conductivity of ER fluids go up with the voltage quickly. Under the high electric voltage, the ultrafine particles are polarized, the plus and minus particles are drawn each other, the particles are put in order and increasing the thermal conductivity.
A Parallel Algorithm for Stiffness Matrix Decomposition Using Threadpool Method
Authors: Chen Jun Tao , Xiao Ming , Liu Hui Bo
Published: November 2012

To shorten calculation time in finite element simulation by using multithreading computer, a parallel algorithm for stiffness matrix decomposition based on threadpool method is proposed. Firstly, a decomposition method of applicability to parallel computation is put forward by transferring the Cholesky's LLT method. Then, the threadplool is employed to generate multithreading for repeating use and the optimization is conducted considering load-balancing of each thread. Finally, numerical tests by using proposed algorithm in decomposition of one-dimensional array stored stiffness matrix are carried out on different calculation platforms with multi-processors. It is shown that the parallel algorithm can overcome the limitations of OpenMP when being applied in nested loops and is of high efficiency on stiffness matrix decomposition with low platform demands. The algorithm has explicit concept and minor programming difficulty and is applicable to solve problems caused by limitation of OpenMP in particular.
Information Flow Molding Technology of GBIM
Authors: Yang Ming Yu , Chen Si Yuan , Xu Jian Ying
Published: November 2012

Green Building and Information Model are the focus and developing tendency in the future. Therefore, the combination of the two will push and accelerate the progress of Chinese Green Construction forward. Thus this paper attempts to introduce the idea of GBIM, which takes information flowing technology as the nucleus, is the compound of data integration of BIM and integral management, is also the integration of information exchange and concordance for the tool software at different phases and in different professions with green construction process and tasks. At last, this information flow technology is applied to information flow model building in the green construction planning and designing.
Numerical Simulation Analysis of Soil Nailing Wall Based on FLAC during the Excavation of the Foundation Pit
Authors: Chen Chang Wen
Published: November 2012

On the basis of a typical engineering, a foundation of soil nailing walls supporting simulation model of soil nailing on the structure of the excavation is established with FLAC, the construction process of the supporting structure is analyzed in the dynamic simulation. The deformation characteristics of the supporting structure are analyzed during the construction process, the law of the supporting body deformation with the difference of excavation steps is summarized. The situ test data of the deep foundation horizontal displacement and vertical displacement are obtained by testing in situ. Some useful conclusions are summarized by comparative analyzing the numerical simulation value and situ test data, providing guidance for the design and construction of the pit soil nailing wall.
Simulation Research of PV Module in Islanded Operation State
Authors: Li Wei Jie , Wang Xiao Hui , Ma Shao Xia , Wang Jing
Published: November 2012

The islanded operation state of photovoltaic (PV) module was simulated and analyzed. PV cell was modeled according to its working principle and its running characteristics were discussed in different environment conditions. The maximum power point tracing and constant voltage regulation methods were used to adjust the output power and voltage. A PV cell module with a load was simulated and the simulation results can provide references for the development and application of renewable energy.
Cross-Sea Bridge Construction Contract Management Research
Authors: Yang Liu Liu , Qiu Hong Sheng , Wang Cheng
Published: November 2012

The cross-sea bridge construction environment is poor, and its construction technology is complex. To determine the general contract management idea, realize the overall operation goal, achieve the standardized management and maximized and optimized benefits of the engineering project, it is of great practical significance to discuss the management of the cross-sea bridge construction contract. The construction enterprises should pay attention to the management of construction contract, which is as the basis of arranging for construction, pursuing for claim, controlling engineering cost and settlement and providing possibilities for risk transfer, carry through the real-time institution development and establish the contract management system, so as to control the business cost and drop the business risk. Incorporated with the actual situation of the construction contract signing, the issues and improvement measures in the signing and management of the cross-sea bridge construction contract are given.
AHP-Based Research on the Selection of Construction Project Subcontractor
Authors: Cheng Min , Ma Guang Xia , Sun Jin Kun
Published: November 2012

AHP is usually adopted by design-build enterprise to help to make decision in subcontractor selection and build hierarchical structure for the target and evaluation factors which both may affect the selection decision, and meanwhile propose a proper analytical mode and calculation method. This paper takes an concrete engineering example as research object, and the research result shows that AHP can give the priority to impact factors among various factors and obtain the order of comprehensive weight of each impact factors, and eventually help to select a satisfactory subcontractor. This method reduces the influence from personal factor and enhances the objectivity and scientific of each decision.
Research on Pile Foundation of Transmission Tower Stability Analysis Based on Numerical Simulation in Karst Areas
Authors: Zheng Jin Bei , Zhang Hu , Liu Bao Qiang , Liu Gao , Fan You Ping , Hua Shuai , Jiang Dai Xing
Published: November 2012

The stability of the karst area transmission towers pile foundation and engineering deal with the problem, the success or failure related to the electric power system operation, the karst area transmission towers pile foundation stability of the subject, the power sector is currently no in-depth case studies, qualitative analysis has been used method and semi-quantitative analysis of the reliability of the method of evaluation results is restricted, and thus how to seek a more rational analysis method and its application in theory worthy of further exploration. In this paper, numerical simulation conducted in-depth study and exploration of a karst area transmission tower pile stability evaluation, design, construction and operation of the project has a certain reference value, has certain reference significance for similar construction projects.
Settlement Analysis of Single Large-Diameter and Super-Long Bored Piles in Cohesive Soils
Authors: Zhang Rui Kun , Shi Ming Lei , Wang Jin
Published: November 2012

The behavior of single axially loaded large-diameter and super-long bored piles have large difference to single small diameter short piles. The article analyzes the load transfer characteristic of single axially loaded large-diameter and super-long bored piles in deep soft clay in the Yangtze River Delta region. And the hybrid method of finite element analysis of rod structure coupling with the shear displacement method for single pile was utilized to simulating and predicting the single pile performance. It is verified that the settlement calculation hybrid method in this paper is reliable.
Stability Analysis and Control Measures of the Kim-Yun-Mine Collapse
Authors: Zhang Shan Shan , Wu Yu Liang
Published: November 2012

Collapse is one of the major geological disasters all over the world and threats to life and property safety of people. To make a better understanding of the reason it occurs and how to deal with it, the Kim-Yun-Mine collapse is researched. There are one dangerous rock mass and two collapse accumulation body. The basic characteristics of the collapse is described clearly according to the geological exploration data, and the stability of the dangerous rock mass and the collapse accumulated body is analyzed in the way of engineering geology and stereographic projection. At last, we put forward comprehensive control measures based on the results of stability analysis and collapse characteristics.
Selection of Support Form and Water-Sealing Measure for Deep Excavation in Miscellaneous Interphase Distribution Strata
Authors: Yuan Hua , Yuan Pei
Published: November 2012

This paper summarizes the possible supporting forms of deep excavation which will provide some useful suggestions for retaining structure pattern selection based on the geological characteristics of foundation soil in Kaifeng. Then combing with the irregular-shaped deep excavation of certain civil air defense engineering, a comparatively effective waterproof measure is proposed. Moreover possible problems encountered in the process of construction are discussed, and their corresponding solving ways are illustrated systematically. The research results will contribute to choose the supporting pattern and water sealing measure for deep excavation in Kaifeng region.
Structural Damage Detection of Unsaturated Soil Embankment Slope Based on Artificial Neural Network under the Rainfall Infiltration
Authors: Wang Yu Jie , Si Wen Jing , Gao Ying Fu , Zhou Hui
Published: November 2012

Based on BP neural network, simulation analysis of damage location and degree of unsaturated soil embankment slope under rainfall infiltration are made using finite element method. The simulation model is established by rainfall infiltration statistical characteristics as the main input vector. The results show that the artificial neural network can accurately identify the damage location and the damage degree of the slope.
Unified Solution of Passive Earth Pressure for Unsaturated Soils
Authors: Zhang Chang Guang , Zhu Dong Hui , Gao Zhi , Xue Guang Wei , Li Zheng
Published: November 2012

With two different distributions of matric suction, the unified solution of passive earth pressure for unsaturated soils is obtained, which is based on the unified shear strength for unsaturated soils in terms of two independent state stress variables and could avoid some shortages of Rankine's passive earth pressure. The influence of intermediate principal stress and matric suction on passive earth pressure is discussed. The results show that the passive earth pressure increases significantly with the unified strength theory parameter or matric suction increasing, and does not change more rapidly when matric suction decreases linearly with depths than that is constant.
Fractal Description of Rock Mass Structure Representative Elementary Volume
Authors: Zhang Ting Ting , Yan E Chuan , Hu Xian Ming , Cao Yang Bing
Published: November 2012

The mechanical parameters of the rock masses are scale dependent because of the existence of the discontinuities. The self-similarity of the discontinuities makes the application of fractal theory in the description of the rock mass structure possible. The novel point in this study is that the structure representative elementary volume (SREV) of rock mass is proposed. Rock mass structures were obtained through the two-dimensional discontinuity network simulation results, from which ten pieces of square rock mass specimens were chosen. The side lengths of the specimens were increased in turn from 1m to 10m. And the fractal dimension of each specimen with different sizes was calculated by the box-counting principal of the fractal geometry. The fractal dimensions of the rack mass structures became larger with their side lengths increasing, and finally stable. And the SREV of the rock mass was determined based on the variation rule of the fractal dimensions. Further, the relation between the structure representative elementary volume (SREV) and mechanical parameter representative elementary volume (REV) was qualitatively analyzed from the strength differences between the discontinuities and intact rock. And the conclusion was inferred that the size of the SREV was the upper limit of mechanical parameter REV. Meanwhile, the conclusion was verified by the results of the finite element method. This study can provided a referring value for the estimation of the mechanical parameter REV in future.
The Influence of Dehumidifying Condition on Expansive Soil Engineering Properties
Authors: Li Xiong Wei , Wang Ai Jun , Dai Guo Zhong
Published: November 2012

The expansive soil behaviour of expansive deformation and shear strength is deeply influenced by humidity condition. Different soil drying rate was set with constant temperature and different relative humidity. When saturated soil samples was dried to the different predetermined water content, the expansion ratio test with the upper load was made. It is shown that in the condition of high relative humidity, the expansion ratio is high. The smaller initial water content and upper load may lead to a larger swelling deformation. When soil samples with different initial water content was fully expanded, the consolidated direct shear tests were made. It is shown that the smaller drying rate leads to the greater shear strength after full expansion. What’s more, the upper load may improve the soil shear strength.
Strength and Deformation Characteristics of Stabilized Silty Soil
Authors: Zhao Zheng Rong , Yang Hong Xia
Published: November 2012

Combined with the silty soil characteristics of the Yellow River alluvial plain and the subgrade filling of Ji-He expressway, the paper discusses silty soil, stabilized silty soil strength and stress-stain characteristics through the indoor triaxial shear test. The results show that the remodeling silty soil has obvious peak, brittle failure, low residual strength after being destroyed and the stress-strain curve shows a softening type in confining pressure 100kPa lower stress level. In the confining pressure 400kPa higher stress level, soil samples peak is not obvious,mainly plastic failure and the stress-strain curve is close to a hardening type. Compared to mixed with 8% lime, stabilized silty soil of mixed with 4% cement and 4% lime shows that the partial stress peak is more obvious when destroyed and the residual strength is drastically reduced and more incline to brittle failure. In different the age, compared to mixed with 8% lime, stabilized silty soil of mixed with 4% cement and 4% lime shows that internal friction angle becomes larger and cohesion improves gradually whose amplitude is much larger than internal friction angle. Therefore, a more effective way to stabilize the silty soil of the Yellow River alluvial plain is to select silty soil mixed with 4% cement and 4% lime.
Study for Quantitative Analysis of Loess Microstructure Influence
Authors: Song Peng Ran , Wang Chang Ming
Published: November 2012

Microstructure is a important index of soil physical, mechanical and engineering properties, SEM images and computer image processing technology make the soil microstructure research developing rapidly in recent years, but the researches on the influence factors and important degree are rare. Process the images form scanning electron microscopy test with the image processing toolbox of MATLAB. Fractal dimensions, porosities and pore size distributions are calculated in different analyzing windows, thresholds and magnifications. The results show that:1) As the results of the experiment influenced greatly by the smaller analyzing windows, in order to get the real calculation value, the medium section was processed; 2) Fractal dimension values are less influenced than porosities and pore size distributions by different thresholds; 3) Too big magnification can cause inaccurate fractal dimensions. Porosities and pore size distributions are inverse growing with increasing of magnification.
Pseudo-Dynamic Test Analysis of Rigid Pile Composite Foundation
Authors: Sheng Gui Lin , Liu De Hui , Bao Peng
Published: November 2012

According to the similarity theory, this paper established a geometric similarity 1:10 and 3 × 3 rigid pile composite foundation pile group model. Pile strain , cushion deformation and flask displacement were obtained through pasting resistance strain gauges in pile, embedding strain gauge in cushion, connecting to displacement sensor at out of flask, etc., basing on pseudo-dynamic test method. These date were analyzed and studied, and then can conclude the response pattern under earthquake action on rigid pile composite foundation, which provide a basis for application of rigid pile composite foundation in practical engineering.
Finite Element Analysis of Cushion Thickness and Ultimate Bearing Capacity of Lime Soil Pile Composite Foundation
Authors: Wei Zi Sen , Zhang Yong Mou , Peng Dong Hui
Published: November 2012

The static load test of composite foundation was simulated by using the nonlinear finite element programs, and the changes of the pile-soil stress ratio and the pile and soil settlements as well as the plastic deformation of composite foundation were analyzed. The simulation results show that: the cushion of flexible pile composite foundation can effectively regulate the pile-soil stress ratio and make the bearing capacity of the lime soil pile and the soil between piles give full play at the same time. The cushion has a distinct role in reducing the pile settlements, however, has little effect in reducing the soil settlements. The reasonable cushion thickness is about 300mm. The composite foundation will emerge local shear failure when it reaches the ultimate bearing capacity. Reducing the pile spacing can increase the ultimate bearing capacity, and the rate of increase shows a gradually increasing trend.
Influence of Groundwater Seepage during Foundation Pit Dewatering on Soil’s Effective Stress
Authors: Yuan Hua , Hong Yan
Published: November 2012

Engineering dewatering not only makes soil release gravity water, increasing soil self-weight stress, but also lead to seepage occur along the two sides of waterproof curtain driven by water head difference inside and outside the pit, forming a hydrodynamic pressure, which are the main reasons causing ground settlement. In this paper, the equation of groundwater level drawdown funnel curve firstly is deduced, then we investigate the total effective stress increments of foundation pit soil with seepage works alone as well as both gravity drainage and seepage effect work together, and obtained the formulas for soil effective stress increment calculation. Studies show that the shape of soil settlement cross-section is closely related to the characters of water drawdown funnel curve.
Analyze of the Affection of Excavation Unloading of the Rock Mass of the Spillway Tunnel of a Hydropower Station on the Slope’s Stability
Authors: Wang Le Hua , Bai Jun Lei
Published: November 2012

After the excavation of the rock , the rock mass stress state changes and the quality of rock mass damage deterioration. Rock excavation of spillway tunnel of the hydropower station may have some influence on the stability of the tunnel-face side slope. In this paper, combined with the engineering practice, based on the unloading rock mass theory and through two dimensional finite-difference method. Selected seven feature points near the excavation surface as monitoring points for calculation ,then calculated the effect on the stress and strain of the slope caused by the excavation of the spillway tunnel and analysed the changes in the distribution of the slope rock mass plastic zone and the point factor of safety. The results show that spillway tunnel excavation in excavated slope have some impact on the excavated slope stability, and it is more obvious for the effect on stability of excavated slope in considering rock mass unloading effect than do not consider the rock mass unloading effect.
Seismic Behavior of Reinforced Concrete Core Wall under Different Span-Depth Ratio of Coupling Beam
Authors: Jia Peng
Published: November 2012

Two reinforced concrete core wall models with large height-width ratio were built and tested to failure under the combined action of constant axial load and reversed cyclic lateral load. The span-depth ratio of coupling beam on each core wall was focused on. This paper presents the results, including failure mode, hysteretic behavior, load-carrying capacity, ductility, energy dissipation ability. With the span-depth ratio of coupling beam dropping from 1.7 to 0.9, stiffness and load-carrying capacity of the specimen had risen markedly, but the ductility performance dropped significantly. It can be seen that the span-depth ratio of coupling beam having important effect on the seismic behavior of reinforced concrete core wall.
Mechanics Simulation and Analysis of the Main Palaestra of the World University Games during the Unloading Process
Authors: Zheng Jiang , Hao Ji Ping
Published: November 2012

The steel roof of main palaestra of the World University Games is a long span space structure of single-layer fold face reticulated shells. The space positioning installation of members of this structure is very difficult, and the control accuracy is very high. In order to improving the installation accuracy of this space structure during the construction, a method named bulk-way assembly technology at high altitude with multi-points supporting had been adopted. After the closure of the steel roof structure the temporary supporting jigs began to be uploaded. During this process the supporting jigs quit work gradually and the main structure began to carry the load. Different uploading way will make different influence for the main structure and supporting jigs during the uploading process. These have to be considered in the structural design and construction stage. This article adopts construction mechanics and FEA method to analyze the uploading procedures according to the real construction process in order to finding the actual internal force and deformation and ensuring the security of the structure and supporting jigs. Lots of results have been obtained as guidelines in theory for the design and construction.
Nonlinear Analysis of Prestressed Cold-Formed U-Shaped Steel and Concrete Composite Beams
Authors: Yu Jian Jun , Wang Lian Guang
Published: November 2012

Cold-formed U-shaped steel and concrete composite beam is a kind of composite beam which the steel and the concrete are integrated by welding connections on the cold-formed U-shaped steel and then pouring concrete on the steel. Now, many experts and scholars have carried out many experimental research and theoretical analysis about it. But, prestressed Cold-formed U-shaped steel and concrete composite beams have not been studied. Based on the structure , the nonlinear analysis mode of prestressed cold-formed U-shaped steel and concrete composite beams is proposed, the calculating program is researched. The calculating results show that the bearing capacity of composite beam increases with the increments of thickness of steel plate and concrete strength, and the thickness of steel plate has a larger effect than the width of the flange plate of concrete, applying prestress can enhance the bearing capacity and flexural rigidity of the composite beam.