bluuebunny/crossref_metadata_2025_split huggingface dataset:
Calculation methods for reinforcement at the edge of epoxy joints of precast segmental box girders based on STM
Authors: Aimin Yuan , Xueru Zhao 
Published: September 2019

Abstract
To study the failure mechanism caused by diagonal crack near the joints in precast segmental box girder, a finite element model (FEM) of a standard segment of precast segmental box girder under pure bending was established. The stress field distribution for a selected segment was obtained by numerical analysis. Topological optimisation was adopted to determine the load path through the standard segment. Then, a strut-and-tie model (STM) for the standard segment under pure bending was established and verified, and calculation methods and formulae were provided for determining the reinforcement requirement at the edge of epoxy joints and at the middle of the web of the segments. Finally, a standard segment from the Fourth Nanjing Yangtze River Bridge was taken as an example to check the requirement for vertical reinforcement at the edge of the joint and horizontal reinforcement in the web, using the proposed STM. The results show that, using the STM for a standard segment when designing the reinforcement required at the edge of the joints and at the middle of the web, is acceptable, which further validates the feasibility of the proposed method.
Primary Chemical - Physical Properties of Marine Cement-Based Materials
Authors: Yan Qian , Wang Ya-jun , Liu Tao , Wu Di , Xu Yan-jie , Gan Xiao-qing , Dong Zhi-hong 
Published: September 2019

Abstract
The uniaxial pressure experiment was carried out on the whole-age marine cement-based materials. By analyzing this type of material, there is obvious early strength and late strength decay. The X-ray diffraction experiment was carried out on the sample before the pressure test. After the crushing, the characteristic samples were taken for multi-scale electron microscopy. The microstructure of the material was divided into the strengthening region and the weak region, and the microscopic damage process was summarized.
Comprehensive Division of Rock Mass Structure in Granite Area--Taking Tianhu Rock Mass as An Example
Authors: Li Yawei , Guo Zhejiang 
Published: September 2019

Abstract
In the stage of sites selection of high-level waste geological repositories, reasonable division of homogeneous zones of rock mass structure is helpful to further analyze the suitability of engineering rock mass quality and construct discontinuous fracture network model. Based on accurate measurement of surface structural planes, the surface rock mass structure in the study area is differentiated by discontinuities spacing, and the homogeneity of rock mass structure is evaluated by linear density index. The results show that the rock mass structure type in the study area is dominated by sub-blocks, and its distribution area accounts for 84% of the total area. The study area belongs to homogeneous rock mass structure with high similarity. Most of the surveying lines in the study area have high correlation and uniform joint density.
A study on the mechanical properties of cement soil added with ferronickel slag
Authors: WeiFan  , Chen Feng 
Published: September 2019

Abstract
Unconfined compressive strength test was employed hereby to study the effect of ferronickel slag content and mineral powder content on strength performance of cement soil. In the experiment, 0%, 10%, 20%, 30% and 40% ferronickel slag were added into the cement soil, respectively, to figure out the comparatively better content of ferronickel slag was 20%. The experiment results also indicate the addition of ferronickel slag also significantly affected the early strength of cement soil, but as the time proceeded, the strength of cement soil added with ferronickel slag fell less quickly as before.
Experimental study on the Influence of Load on Permeability Coefficient of Calcareous Sand
Authors: Shuai Wang , Xuewen Lei , Qingshan Meng , Jieli Xu , Yafei Xu , Lingfeng Xie 
Published: September 2019

Abstract
The permeability coefficient of calcareous sand is an important hydraulic parameter in reef engineering. The loading and permeation tests of calcareous sand and quartz sand under the same conditions were carried out by self-developed loadable sand permeability device, and the influencing factors were studied to obtain the calculation formula of the permeability coefficient of calcareous sand under load, containing void ratio e, particle gradation, permeability coefficient Ks
and the relative crushing rate B

r
proposed by Hardin. The results show that under the same load, the permeability coefficient and compressive deformation of calcareous sand decrease more than that of quartz sand, and the relative breakage rate of calcareous sand increases with the increase of load, while there is exponential correlation between its Ks
and Br
. It can be concluded that the pores of calcareous sand are compacted under load, and the granule breakage leads to gradation change, which affects the permeability coefficient of calcareous sand.
Impact response of reinforced concrete slabs in elastic half space
Authors: Yang Xiaolin , Liu Lingxiao , Wang Genhui 
Published: September 2019

Abstract
The analysis of the mechanical behaviour of reinforced concrete slabs on elastic foundation under impact loads is of great significance in the construction and protection of concrete pavements in airports. Based on the Elastic Half-space Foundation Model and Concrete Damage Plasticity Model, the displacement and stress fields of reinforced concrete slabs under impact loading are numerically simulated by explicit nonlinear finite element method. The result can be used to design and evaluate the safety of foundations and reinforced concrete slabs under impact loads.
The Impact of Lift Joint on the Mechanical Properties of Cemented Sand and Gravel Material
Authors: Cai Xin , Chen Jiaojiao , Li Weixin 
Published: September 2019

Abstract
Cemented sand and gravel (CSG) material is a new kind of geotechnical material. Layered rolling technology is always adopted in the construction of CSG dam, which inevitably creates a weak layer between adjacent CSG material layers. This weak layer is called lift joint. In order to investigate the influence of lift joint on material properties, a discrete micromechanical model of CSG material with lift joint is established based on Lattice Discrete Particle Model (LDPM). Through the three-point bending tests, compression tests and triaxial tests, the parameters for this model are calibrated. Then the impact of lift joint on mechanical properties of CSG material, including compressive, tensile, and shear behavior is studied qualitatively from mesocopic view. The result shows that the weaker the lift joint is, the lower the material strength is, the more impact of the lift joint on the mechanical properties of CSG material is.
Numerical simulation on optimization scheme of permeable hole of permeable sheet piling spur dike
Authors: Shen Shuaihui , Li Yujian , Li He , Guo Zhaojun , Zhou Zhengping , Mao Liang 
Published: September 2019

Abstract
Aimed at the problems about that permeable hole number and permeable hole layout of Permeable Sheet Piling Spur Dike (PSPSD) affecting the flow characteristic at spur dike area, CCHE2D flow simulation mathematical model is adopted, two dimensional flow numerical simulation is carried out for the permeable spur dike area of the physical model of the Qiman reach of the Tarim River main stream. The change law of cross section flow velocity, water level with different permeable hole number and layout are analyzed. The optimization scheme of permeable hole for the PSPSD is sought. The results show that the more number of permeable hole of the PSPSD, the higher the water level upstream of the spur dike, the lower the water level downstream of the spur dike, the smaller the flow velocity upstream and downstream of the spur dike, the better the velocity uniformity. The optimization scheme for the permeable spur dike with the best effect of flow retardation is that the number of permeable holes is 4 holes, and the spacing of permeable hole decreases gradually from the root to the head of the spur dike, which accounts for 9%, 8%, 7% and 6% of the length of the PSPSD respectively.
Experimental study on the microstructure of the lacustrine soft clay after different consolidation deformations based on SEM
Authors: Gan Jianjun 
Published: September 2019

Abstract
In order to study the microstrcutrue of the lacustrine soft clay under different consolidation pressures, SEM and quantitative analysis of consolidation samples were carried out through GDS consolidation undrained tests with different consolidation pressures. A different consolidation stress of 50 kPa, 100 kPa, 200 kPa, 400 kPa, 800 kPa, 1600 kPa and stress rate of 0.01 mm/min were used in this GDS test. The results show that the boundary points of primary consolidation and secondary consolidation of lacustrine soft clay are not obvious at low consolidation pressure. The consolidation pressure increases, the slope of the fractal dimension of porosity rainfall curve is larger and the reduction rate is faster, and the probability entropy is above 0.96. When the consolidation pressure is larger than 400 kPa, with the increase of the consolidation pressure, the slope of the fractal dimension value change curve of porosity slows down. The average shape coefficient increases faster when the consolidation pressure is less than 400 kPa, while the fractal dimension decreases faster. The correlation coefficients between consolidation pressure and fractal dimension value of porosity, probability entropy, average shape coefficient and fractal dimension are all greater than 0.81, showing a high correlation.
The Study of Factors on the Heat Transfer Characteristics of Interface between Cast-in-Place Concrete and Frozen Soil
Authors: Yanjun JI , Yupu HU , Tao LUO 
Published: September 2019

Abstract
The heat transfer characteristics of cast-in-place concrete-frozen soil contact surface directly affect the surface freezing strength of cast-in-place pile, and it is important to study the heat transfer characteristics of cast-in-place concrete-frozen soil contact surface for Pile Foundation design and construction in frozen soil area. Based on the small model pile test, a numerical analysis model is established to calculate the heat transfer characteristics during concrete poured in situ. The results show that the heat flow of 0.5h concrete and the contact surface of frozen soil increases by 381.2% when the pouring temperature raised from 5 to 30°C. The water-cement ratio increased from 0.4 to 0.6, and the heat flux of 0.5h contact surface is reduced by 23.7%. The temperature of the contact surface increased first and then decreased, and the peak is near the liquid limit of soil. When the temperature of frozen soil decreased from -1 to -3°, the temperature of the contact surface increased with the decrease of the temperature of the frozen soil. The thermal conductivity and transformation of the thermal effect of phase transition have played a decisive role. 0~1h (especially 0~0.5h) is the main time for the heat released from concrete to frozen soil.
Causes of Crack and Durability Analysis of Corroded Reinforcing Bars in Three-Orientation Pre-stressed Aqueduct with Long-span at Cold Areas
Authors: Huang Tao , Zhang Guo-xin , Li Jiang , Li Hai-feng , Cheng Heng 
Published: September 2019

Abstract
A large aqueduct located in the cold region of north China adopts three-orientation pre-stressed reinforced concrete structure with large span. During the construction period, after the third spring, the quality inspection of the aqueduct wall has a phenomenon of vertical long cracks, white paste, alkali corrosion and water seepage, and there is also an empty drum sound inside the wall. Using theoretical solution and numerical calculation method, the causes of cracks on the surface and the internal hollow of the aqueduct wall are analysed from the aspects of pre-stressed tension, frost heave and ambient temperature. A nonlinear finite element model with fine mesh is established to simulate the initiation of the crack and penetration process through the single hole and multiple holes frost heaving process of the bellows. Finally, the durability and hazard of aqueduct are evaluated by calculating the influence of different seam depths on the pre-stressed steel bars and ordinary steel corrosion, which provides a basis for the later crack repair protection scheme, and also provides reference for the construction and operation management of such aqueducts.
Influence of Near-field Pulse-like Ground Motion on Seismic Response of Steel-concrete Plate Composite Beam Bridges with Seismic Isolation
Authors: Yao Chunjiang , Li Runqing 
Published: September 2019

Abstract
For steel-concrete composite bridges, different seismic excitations are selected, and nonlinear time-history analysis method is used to study the influence of near-field seismic impulse effect on seismic response of steel-concrete plate composite beam bridges and damping effect of steel-concrete plate composite beam bridges. Under Near-Field Seismic excitation, cable-stayed seismic isolation bearings are used. The seismic responses of main girder displacement, bearing deformation, shear force and pier seismic force are compared and analysed through two directions of input. The influence of impulse earthquake on seismic response of steel-concrete composite beams with isolation bearings is studied. The seismic response of steel plate composite beam bridges is basically smaller than that of non-isolation girder bridge after the isolation bearings are laid out, and the response decreases by more than 40%. The isolation bearings have good damping effect. Therefore, under the action of impulsive ground motion, it is suggested to adopt isolation bearings, such as Cable-sliding Friction Aseismic Bearing.
The rock mechanics and acoustic emission characteristics of rock salt under tension-compression alternating
Authors: Liu Jianfeng , Liao Yilin , Deng Chaofu , Zhang Qiangxing , Li Zhicheng , Zeng Yin 
Published: September 2019

Abstract
In order to study the stress state and acoustic emission characteristics of salt rock energy storage during high frequency injection and production of compressed. the self-developed spring specimen limit tension and compression cycle test rock specimen fixing device based on the MTS815 Flex Test GT rock mechanics test system and acoustic emission (AE) three-dimensional positioning real-time monitoring system was used to study on mechanical characteristics and AE characteristics of pure salt rock and impurity salt rock under tension-compression alternating tests for the first time. The test results show that: (1) Under the stress path of tension-compression alternating, the tensile strength of pure salt rock is 0.95 MPa, impurity salt rock tensile strength increased by 47.37% compared with pure salt rock, axial deformation of impurity salt rock is 0.25mm, while pure salt rock is 1.40 times of it. (2) During the compression stage, AE signals with uniform distribution are produced by the effect of mutual dislocation, slip and micro-defect closure in salt rock, which has a certain end-restraint effect; In the stretching stage, the development of intercrystalline cracks is the main cause of AE signals in tensile stage, and AE signal followed hysteresis phenomenon. (3) Comparing with impurity salt rock, the cumulative ringing counts of the four compression loading and unloading stages are 3.13 times higher than impurity salt rock, AE signal of pure salt rock is weaker during tension loading and unloading, the cumulative ringing count increases slightly, a large number of acoustic emission signals accompany only the final tensile failure process. Under the condition of tension-compression alternating, AE signals of pure salt rock with the same tensile or compressive stress levels are more active than those of impurity salt rock, and the number of AE events in compression stage is larger than that in tension stage.
Applicability of HVSR in site effect of loess slope covered on mud rock
Authors: Wang Huijuan , Wang Ping , Yu Yifan , Xu Shuya , Guo Haitao , Pu Xiaowu 
Published: September 2019

AbstractTaking the loess slope covered on mud rock as a research site, this study is based on theoretical foundation of the Horizontal-to-Vertical Spectral Ration(HVSR) and Sediment-to-Bedrock Spectral Ration(SBSR), site earthquake response of the loess landslide covered on mud rock calculated by use of the software FLAC3D, dynamic response of earthquakes was revealed, the simulation between HVSR and SBSR has been discussed, applicability of HVSR has been was analyzed. The results show that: The maximum horizontal displacement is found in the cliff part of the slope, the peak acceleration is the largest at the back edge of the slope and the vertical interface, as the elevation increases, the dominant frequency moves toward the lower frequency, and the higher frequency components are absorbed, the dominant frequencies obtained by HVSR spectrum ratio and SBSR spectrum ratio, and they are basically consistent with the fourier spectrum, the amplitude of HVSR and SBSR spectrum ratio are similar to the change rule of peak acceleration. Therefore, HVSR method can be applied to study the site effect of loess slope covered on mud rock
Numerical Study on Vertical and Horizontal Seepage Deformation of Silty Soil
Authors: Zhang Canhong , Wang Baotian , Yang Zhanmin , Ji Enyue 
Published: September 2019

Abstract
In this paper, the PFC3D fluid-solid coupling calculation module is used to simulate the seepage deformation process of silty sand under vertical and horizontal seepage. The seepage mechanism such as particle contact, flow field distribution, critical hydraulic slope and particle motion of silty sand under different seepage direction is analyzed. The numerical simulation results show that the critical hydraulic gradient of silt sand in vertical seepage is higher than the critical hydraulic gradient in horizontal seepage.
Finite Element Modeling of Asphalt Mixture Based on Image Recognition
Authors: Lv Yuejing , Jiang Yunyun , Wang Huan 
Published: September 2019

Abstract
This study describes a method for establishing a mechanical model of heterogeneous finite element method. With the combination of digital image recognition technology and the theory of automatic mesh generation, it is possible to establish an inhomogeneous finite element model for mechanical calculation. Firstly, the micro-structure of the two-dimensional mixture is identified. Then all the boundary points are imported into ANSYS. Finally, the finite element mesh model of the micro-structure of the asphalt mixture is obtained by using the automatic finite element mesh generation technology. Taking Marshall specimen as an example, meshing the model proves that the method is feasible.
AE Monitoring Corrosion-induced Deterioration of Reinforced Concrete Piles in The Simulated Marine Environment
Authors: Zhou Yujue , Zhou Yubao , Zheng Yonglai 
Published: September 2019

Abstract
An experiment study was conducted to assess the effectiveness of acoustic emission (AE) technique monitoring the corrosion-induced damage in the marine environment. Three reinforced concrete (RC) piles of 1600 mm long by 200 mm square were casted and then were exposed in a simulated marine environment to reach 5%, 10% and 20% of steel rebar mass loss respectively. Throughout the whole test period, all specimen was monitored by three AE sensors installed at two different heights of the concrete surface and at the end of the steel rebar, respectively. The AE activities were analyzed to determine corrosion-induced dterioration at different corrosion levels. Based on the finding, the effectiveness of AE technique on monitoring of RC piles of high-pile under aggressive marine environmental conditions was established.
Research on Working Status of Impervious Geomembrane along Cracks of High Membrane-Faced Rockfill Dams
Authors: Zhang Xianlei , Zhao Mengdie , Liu Yunfeng , Gu Ke , Mao Wenlong 
Published: September 2019

Abstract
To address the “cramp effect” caused by displacement and sediment of impervious geomembranes in the cracks along high membrane-faced rockfill dams and the problem the declining mechanical performance of the geomembranes caused by long-time tensile stress, this study developed a set of simulation devices according to the working status of impervious geomembranes in the cracks along the dam. With PVC geomembranes as the test material, this study performed tests to identify the law of decline of membrane’s mechanical performance under different conditions of deformation with the temperature of the reservoir unchanged. It used the fractional mathematical model to process the test data and concluded the law of declining mechanical indicators of the PVC geomembrane. On the basis of the test data analysis, this study divided the decline of the geomembrane’s mechanical performance under constant large deformation into two stages, proposed structural solutions to mitigate or avoid decline of mechanical performance and lengthen the service life of impervious geomembranes.
Study on Applicability of Maturity Theory to Predict Concrete Compressive Strength under Non-standard Curing Condition
Authors: Wang Liang , Wu Liqiang , Fang Chunhui 
Published: September 2019

Abstract
The curing temperature of the actual construction site, which has a greater impact on the concrete strength, often fails to meet the standard requirements. This paper studies the effect of curing temperature on concrete compressive strength from the perspective of maturity by designing four curing conditions including standard curing, high temperature curing in summer, low temperature curing in winter, and natural curing, using the artificial climate simulation room. The result shows that the relationship between compressive strength and maturity of concrete under the standard curing condition is basically in accordance with the hyperbolic model, which can be used to predict the compressive strength at different ages; however, when the curing temperature and the standard curing temperature are quite different, the hyperbolic model is no longer applicable; at this point, direct prediction of concrete compressive strength using maturity will lead to significant errors. Therefore, it is necessary to further establish a theoretical model of maturity that takes into consideration the effect of temperature in order to predict the compressive strength of concrete more accurately.
Study on three-point bending mechanics and acoustic emission characteristics of impure salt rocks
Authors: Liao Yilin , Liu Jianfeng , Li Zhicheng , Zhang Qiangxing , Xu Deng , Zhu Anqi 
Published: September 2019

Abstract
In order to study the mechanics and deformation characteristics of salt rock under bending conditions, two groups salt rocks with different impurity content were subjected to three-point bending cycle loading and unloading test and simultaneous monitoring of acoustic emission based on MTS815 Flex Test GT rock mechanics test system and acoustic emission (AE) three-dimensional positioning real-time monitoring system. The research shows that: (1) The average tensile strength of pure salt rock bending tensile is 0.88MPa, and the impure salt rock is 1.72 times of pure salt rock. The impure salt rock has better resistance to crack propagation, and COMDmax and LPDmax are 82.31% and 83.47% of the pure salt rock, respectively. (2) The bending deformation failure of salt rock can be divided into four stages of linear elastic phase, nonlinear phase, post-peak crack stability expansion stage and residual phase. (3) The three-point bending deformation of salt rock is active except for the elastic phase of the line. In general, the three-point bending deformation of the polyhalite salt rock is more active. (4) Impurities weaken the plastic deformation ability of salt rock and increase the degree of brittleness.