bluuebunny/crossref_metadata_2025_split huggingface dataset:
Properties and Engineering Influence of Corewall Filter I with Different Fine Particle Contents
Authors: Huifeng Zheng , Guanye Wu , Yi Chen , Lai Sun , Hua Fu 
Published: September 2019

Abstract
The protection provided by filter I for the corewall constitutes an important safety guarantee for the impervious bodies of corewall dams. In particular, the fine particle content (the content of particles < 0.075 mm in size) of filter I provides a filter protection effect for the corewall. Furthermore, this also determines its own drainage characteristics as an important gradation requirement for filter design. In practical engineering, due to the nature of the aggregate source, the crushing and screening process, and rolling construction, the fine particle content may exceed relevant standards. Relying on the field measured gradation envelope of the filter of a gravelly earth core rockfill dam project, this study prepared two classes of filter I (i.e., filter I of class I with a fine particle content of 8%, and filter I of class II with a fine particle content of 12%). Permeability property test, large-scale compression test, large-scale static triaxial test, and large-scale dynamic triaxial test were conducted. Furthermore, dynamic finite-element calculation of the dam under seismic action was performed, and the anti-seismic liquefaction property of the filter was analyzed. According to the permeability property test, the permeability coefficients of the two classes of filter I were both 1∼5×10−3 cm/s. Lower content of particles < 0.075 mm in size increased the permeability coefficient. According to the mechanical test, the stress-strain test curves of both classes of filter I presented nonlinearity, compressive hardening, elastoplasticity, and other general laws. The strength index and deformation resistance both increased with increasing relative density. Under the same relative density, both strength index and deformation resistance declined with increasing fine particle content. According to the dynamic finite-element anti-seismic liquefaction analysis on filter I of class II (with a content of particles < 0.075 mm in size of 12%) under seismic action, the liquefaction degree had a maximum value of 0.58 (less than 0.8), and the anti-liquefaction safety coefficient had a minimum value of 1.72, which would not trigger liquefaction of filter I. This experimental study and computational analysis offers references for the exploration of the gradation design of filter I of earth core rockfill dams and investigates the related engineering influence.
Effect of cement/lime additive on clogging of vacuum-drain consolidation
Authors: Fu Hongtao , Chai Jinchun 
Published: September 2019

Abstract
All Addressing dredged slurry with high water content has become a critical issue for sea channel dredging and maintenance. Vacuum consolidation is an effective method for improving dredged slurry. Conventionally, the effect of a cement/lime additive on the clogging of vacuum-drain consolidation has been elusive and unclear. To study the effect of vacuum consolidation for soft clayey soils with high initial water content, a set of oedometer tests and vacuum consolidation tests were conducted by adding small amounts of cement/lime. The results indicated that the structural yield stresses of soils with cement and lime were 94.29% and 48.57% higher, respectively, than those of untreated soils. The final surface settlement of lime additive at the end of the tests was 59.68 mm less than that of soil without any additives, and that of the cement additive was close to that of soil without any additives. However, the dissipation of pore water pressure with cement/lime was more than that with untreated soil. The water content was higher when using cement/lime additive, but the vane shear strengths were greater than that of untreated soil at the end of the tests. In addition, the values of k
e2/k
e1 (k
e2 is a permeability at approximately 0.2 m away from the drain, and k
e1 is a permeability close to the drain) above and below the drain were less than those for untreated soil. This clearly indicated that the presence of lime/cement was effective in alleviating the problem of clogging around the drain. This study could provide a good technical guideline for vacuum-drain consolidation projects combined with the use of cement/lime.
Experimental Study on Mechanical Properties of Recycled Concrete with Different Length of Waste Hybrid Fibers
Authors: An Hao , Tian Sisi , Hu Zhengfu , Pei Changchun 
Published: September 2019

Abstract
The mechanical properties of concrete are reduced due to the defects of recycled aggregate itself. In this paper, the fluidity, compressive strength, splitting tensile strength, flexural strength and modulus of elasticity of recycled concrete with hybrid waste fibers were tested by changing the length combination of waste polypropylene fibers and basalt fibers. The test results show that the hybrid fibers can reduce the fluidity, compressive strength and elastic modulus of recycled concrete, and 19 mm waste polypropylene fibers and basalt fibers can significantly improve the splitting tensile strength, flexural strength, brittleness and crack resistance of recycled concrete.
Numerical Study on Temperature Field of Recycled Aggregate Concrete-Filled Steel Tubular Columns Under Fire
Authors: Chen Zheng , Liu Wenchao , Zhang Kesheng , Wang Ruwei , Ren Lele 
Published: September 2019

Abstract
In order to study the characteristics of the temperature field and variation law of steel pipe recycled aggregate concrete column in a fire hazard, this paper takes the thickness of steel pipe and the type of concrete material as the main parameters to carry out fire resistance test of six concrete steel columns simulated by ABAQUS and conducts finite element analysis of the temperature field inside the test piece. The result shows that both the steel pipe recycled concrete column and the ordinary steel tube concrete column have a temperature platform during heating, and their temperature rise is feature hysteresis; the thickness of the steel pipe has little effect on the internal temperature rise while the concrete material is the main factor affecting the heating rate, so steel pipe recycled aggregate concrete column is better fire-resistant. The constitutive model based on the modified parameters in European EC4 specification is used for finite element analysis, and the FEM simulation result is well fitted with the experimental data.
Dynamic parameter identification of a super tall building based on field measurement
Authors: Xiong Chunbao , Niu Yanbo 
Published: September 2019

Abstract
This work aims to identify the dynamic parameters (i.e. natural frequencies and damping ratios) of a super tall building under construction (i.e., Tianjin 117 Tower). Real time kinematic - global navigation satellite system (RTK-GNSS) receivers are applied to monitor the vibration of the structure. Considering the errors of receivers, a joint denoising method is proposed to weaken the influence of noise. Meanwhile, random decrement method (RDM) and fast Fourier transform (FFT) are adopted to derive the dynamic parameters of the structure. Moreover, the identified results from field measurement are compared with predicted values obtained from finite element model (FEM) of the structure. The outcomes of this study are that: (1) the proposed joint denoising method can be employed to weaken the RTK-GNSS observation errors; (2) the first natural frequency of the structure is derived successfully based on FFT analysis, and it agrees well with the finite element results; (3) the damping ratio of the structure is obtained by using RDM.
Effect of the interaction between rebar and concrete cover on the concrete compressive strength
Authors: Li Zhenbao , Yu Chunyi , Ma Hua , Xie Yongping , Zhenyun Tang 
Published: September 2019

Abstract
In order to analyze the effect of rebar size on the compressive strength of concrete cover, the axial behavior of a prism with a central rebar was experimentally and theoretically investigated. The test results indicated that the concrete compressive strength with rebar was relatively smaller than the axial compressive strength of prism that was similar with the concrete strength of cylinder. Further, the degree of reduction in the concrete compressive strength increased as the diameter-thickness ratio increased. Moreover, based on the test results and walled cylinder theory, the influence of rebar on the concrete compressive strength can be better understood. Lastly, in the structural design, the small rebar size and big concrete cover thickness should be chosen so that the effect of splitting action on concrete cover was weaken.
GFRP Reinforced Concrete Adhesion in Low Temperature Environment
Authors: Derui Huang , Wei Jiang , Kuizhou Liu , Yujie Shen , Zhonghua Huang , Yang LI 
Published: September 2019

Abstract
In order to study the bond properties of GFRP reinforced concrete at low temperature, a test device for mechanical loading and strain testing at low temperature was designed and developed. The effects of temperature, diameter of GFRP bar and bond length of GFRP bar and concrete on the bond properties of FRP bar concrete were studied. The study shows that the temperature is reduced from -10 °C to -30 °C, and the bond performance of GFRP reinforced concrete is increased by 15.5 % to 40 %, and the bond performance is enhanced by the load. Adhesive properties also become smaller as the bond length and GFRP diameter increase.
Experimental study on impermeability of concrete lining joint
Authors: He Xiaonan , Guo Xiaohong , Li Sen , Xu Guodong 
Published: September 2019

Abstract
In tunnel and shaft construction, the impermeability of concrete lining joint is involved with the safety of the lining structure. The chloride ion diffusion test is used to test the impermeability of concrete sample. The orthogonal test is designed with three factors, including water-cement ratio, waterproof interface form and prestress load. Each factor establishes three levels. The test results show that the interface form has the greatest influence on impermeability, followed by the prestress load, which can be used to optimize the design of concrete lining joints.
Structural durability and concept system of structural reliability
Authors: Jitao Yao , Liuzhuo Chen , Jun Gao , Ren Xin 
Published: September 2019

Abstract
Research on durability is vital for reliability analysis and control. The main aim is to analyze the deterioration of concrete structures resulting from material degradation. While there is still a large difference in understanding the concept of the structural durability, and a misunderstanding of the relationship among safety, serviceability, and durability, which influence the process of establishing the structural reliability concept system, and the analysis and control of structural durability. Based on former researches and the definition of “condition limit state” in an international standard, the concept of structural durability and the relationship among safety, serviceability, and durability of a structure are elucidated clearly. Furthermore, the basic solution to durability analysis and control is put forward, and the concept system of structural reliability is built. The research will lay the foundation of defining the structural durability uniformly, measuring the structural durability reasonably, and analyzing and controlling structural reliability and structural durability effectively.
Effects of soil grading and sand content on soil-cement properties
Authors: Yao Xianhua , Guan Junfeng , Bai Weifeng 
Published: September 2019

Abstract
The effect of soil-cement characteristics, unconfined compressive strength (UCS), dry density, and water absorption on the soil grading and sand content of six groups (natural soil, ≤ 2 mm, ≤ 1 mm, ≤ 0.5 mm, ≤ 0.25 mm, and ≤ 0.075 mm) of soil-cement block was studied. The results showed that the characteristics of soil-cement mixed with sand were influenced by soil grading. Better characteristics of soil-cement soil were obtained when the soil particle sizes of soil-cement were less than 0.075 mm of mixed sand. Every soil particle size has optimal sand content. Results showed that the optimal sand content of natural soil is 40%, whereas those of other soil particle sizes are all 55%. The results also showed that the UCS of 28-day ages is 1.79 times that of natural soil for soil-cement mixed with sand of ≤ 0.075 mm particle group, whose water absorption is 50% that of natural soil as the optimal sand content. Finally, the study of clay content showed that there exists an optimal clay content for various size groups, namely, 9.12%, 7.06%, 8.08%, 9.05%, 11.36%, and 13.60% for natural soil, ≤ 2 mm, ≤ 1 mm, ≤ 0.5 mm, ≤ 0.25 mm, and ≤ 0.075 mm, respectively.
The Low Viscosity Loess Liquefaction and its Microstructure Analysis
Authors: Dengjin  , Lina  , Lipin  
Published: September 2019

Abstract
Low viscosity powder loess is widely distributed in loess plateau areas of northwest China. It has a high liquefaction potential. the mechanism of low viscosity loess water action is studied using CT scanning. CT scanning results showed that initially, water in loess will tend to rise as a whole. Then, cement salts around the loess grains melt and form large holes. Finally, deformation collapse and damage can occur. In this study, low viscosity loess is compared with sand loess and clayey loess obtained from Lanzhou, Guyuan, and Tongguan. Based on the results of dynamic triaxial torsion tests, the low viscous powder loess dynamic loading time was shorter and more easily liquefied than sandy loess and clayey loess. Electron microscope scanning of loess microstructures showed the chemical element ratios around the loess particles produced cemented material (such as Ca/Fe). The chemical elements around loess particles and the pore diameter/grain ratio were selected to evaluate liquefaction resistance in loess. In addition, loess particle size distribution and the pore/grain ratio also influenced the liquid level. It is an effective innovative method to judge the liquefaction strength of low viscosity silt based on microcosmic parameters.
Experimental Research on Mechanical Properties of Frozen Sands under Isotropic Compression Conditions
Authors: Luo Fei , Lei Jian , Lv Siqing , Xi Yuxuan , Song Zhijie , Zhang Junkai 
Published: September 2019

Abstract
The K-G model has better practicability and superiority than the E-μ model. Conventional triaxial tests of frozen sand samples were carried out at -10 C under confining pressures of 0.5 MPa, 1.0 MPa, 2.0 MPa, 4.0 MPa and 6.0 MPa. During the consolidation process, the samples behave an isobaric state. While the confining pressure σ3 is unchanged, axial pressure σ1 is gradually increased during the shearing process. The test results show that the volumetric strain increases nonlinearly with the increase of the volumetric stress in the isobaric state, showing a power function trend. An improved K-G model is proposed to describe strain softening of frozen sand during shear. The verification results show that the model has good applicability.
Research Progress and Prospects of Soil Pollution Assessment and Prediction Models
Authors: Li Xiuxia , Zhu Wei , Qin Yufang , Yin Fei 
Published: September 2019

Abstract
Soil pollution has become a worldwide environmental problem. The assessment and prediction of soil pollution status is also the focus of scholars at home and abroad. In general, the soil pollution assessment and prediction has experienced the field investigation phase, the statistical analysis phase and the process simulation phase, each of which reflects different levels of the discipline. With the enhancement of today’s big data processing technology and management capabilities, as well as the increasing popularity of aerial remote sensing(RS) and unmanned aerial vehicle (UAV) low-altitude RS applications in the environmental field, it is necessary to integrate these new technologies in time to develop highly efficient models to provide strong technical supports for soil pollution control and restoration decision-making.
Study on Concrete Stress during Construction for Large Pumping Station Flow Channel Structure under Thick-layer Pouring Condition
Authors: Zheng Xuerui , Shen Zhenzhong , Qiang Sheng , Xu Pu 
Published: September 2019

Abstract
Large pumping stations have the characteristics of complex structure, large amount of concrete pouring block, easy cracking of concrete and long construction period, etc. For the stress safety of the flow channel structure during construction period, temperature control simulation for a large pumping station during construction period is carried out. By comparing and analyzing the variation law of temperature field and stress field of the two types of pouring layers which are one 6m layer and two 3m layers, the influence of thick-layer pouring on concrete stress is studied. The simulation results show that thick-layer pouring may cause the increasement of tensile stress peak in concrete structure, but this adverse effect can be eliminated by appropriate temperature control measures. The effect of the same temperature control measures on the reduction of tensile stress of thick-layer concrete structure is more obvious. Thick-layer pouring can shorten the construction cycle of pumping station under the premise of ensuring safety which has a wide application prospect in the field of concrete construction.
Seeping Performance of Reinforced Concrete Slab Dam
Authors: Tao Liu , Qan Yan , Youbo Wang , Zhan Xiong , Yajun Wang , Gan Xiao-qing , Dong Zhi-hong 
Published: September 2019

Abstract
Taking the panel dam as the research object, the finite element simulation analysis and the design working condition scheme comparison method are used to study the impermeability of the panel dam. The results show that the anti-seepage system is the key guarantee for the safety of the dam body, and it plays an important role in the anti-seepage safety of the dam system under the limit state. At the same time, the complete and effective upstream and downstream anti-seepage drainage system has obvious effects on the overall safe operation of complex hydraulic large-scale systems such as reinforced concrete face rockfill dams.
Chemical-Physical Mechanism of Marine Sediments
Authors: Wang Mingyuan , Shan Zhigang , Liu Tao , Xiong Zhan , Yan Qian , Wang Yajun 
Published: September 2019

Abstract
The target material of this study is the marine depositions from Eastern Seas of Zhejiang. The comprehensive experiments were implemented to discover the chemical-physical mechanism and the micro-fabric of the target material. The results of this study will help many maritime explorations such as geophysical prospection, coastal reinforcement, resource exploitation as well as marine structure establishment.
Effects of nitrogen application on growth and yield of maize
Authors: Han Xiaonan , Han Nana , Zhou Qingyun , Kang Jie , Bai Xinyan 
Published: September 2019

Abstract
The effects of different nitrogen application levels on growth, dry matter accumulation, SPAD value, leaf area index and yield of maize were studied to provide theoretical basis for rational and efficient nitrogen application management of crops. In the field experiment, 225, 337.5, 450, and 675 kg ·hm−2 nitrogen application levels were set, respectively expressed by N1, N2, N3, and N4. N0without nitrogen fertilizer was used for the control experiment. During the growing period, plant height, leaf area index and SPAD were observed, and dry matter accumulation, yield and yield components were counted. The growth index, dry matter accumulation, yield and yield components of maize were influenced by different fertilization levels. When the nitrogen application amount is greater than 225 kg · hm−2, it could significantly promote the growth and development of corn and increase the yield. Through comparative analysis, it was concluded that when the nitrogen application amount was 280kg·hm−2, it was the optimal nitrogen application amount for the efficient production of corn in the experimental area.
Construction Simulation and Real-time Monitoring Research of Concrete Dam Based on BIM
Authors: Ji Shunwen , Hu Tianhan 
Published: September 2019

Abstract
Concrete is a complex multiphase composite. Along with the hydration reaction, the thermal and mechanical properties of concrete continue to increase, resulting in deformations such as temperature, autogenous volume and shrinkage, and stress and creep after being restrained by themselves and externally, further cracks are formed. Through finite element simulation, the key parts of temperature control and crack prevention of concrete dam can be predicted, and targeted crack prevention measures can be proposed. Therefore based on BIM technology and combined with simulation results, this paper conducts real-time monitoring of concrete temperature and stress during construction. Through comparison and inversion analysis, the whole process dynamic management of temperature and stress during dam construction period is implemented, and temperature control measures are optimized in real time to realize the whole process control of temperature control and crack prevention of concrete dam.
Study on Sediment Management Strategy of Sandy River Reservoir
Authors: Jinqiong Zhao , Guanghui Rao , Junjie Hua 
Published: September 2019

Abstract
The establishment and operation of one hydropower complex will change the movement law of water flow and sediment of the river way, and sediment deposition is difficult to avoid. Due to the characteristics of “high utilized water head, small reservoir storage, high sediment content and particle hardness” of proposed Upper Arun Hydroelectric Project, this paper applies one-dimensional hydrodynamic & sediment model to studying the movement law of flow and sediment of 3 different sediment management strategy, then finding the rational one which can not only maintain a sustainable live storage of the reservoir by sediment flushing, but also reduce sediment abrasion to turbines. The results show that, when the proposed fully open of all low-level outlets for sediment flushing being implemented during high flow periods, the difference of sedimentation is relatively minor, which all 3 options can effectively maintain the live storage of the reservoir thereby minimizing deposition of sediment at the places that will affect project operation. Therefore, the selection of sediment management strategy should depends on the comprehensive technical and economic comparison. Due to the advantages of relatively short outage periods, conventional technology of construction and the largest Net Present Value, the appropriate sediment desilting operation mode is applying a sediment bypass tunnel with its intake located in the middle of reservoir, and meanwhile utilizing the reservoir’s sedimentation effect, to reduce sediment content transported through the turbines.
Experimental Study on the Triaxial Stress-strain Curve of Undisturbed Loess in Xining by Freeze-thaw Cycles
Authors: Li Shuanghao , Li Yuanxun , Gao Xinya , Shi Dongmei 
Published: September 2019

Abstract
The undisturbed loess in the high-altitude and high-altitude Xining area was studied. The triaxial shear tests of different freeze-thaw cycles and different confining pressures were carried out to investigate the stress-strain changes of undisturbed loess before and after freezing and thawing. The test results show that: (1) different stresses are applied to the samples to show different stress-strain curves. Low confining pressure is strain softening; high confining pressure is strain hard. (2) When the number of freeze-thaw cycles is 0, 1 time, the initial stress phase at different confining pressures is interlaced; when the freeze-thaw cycle is 3 times, in the later stage of strain, the growth rate is 30%-50%. The freeze-thaw effect has a great influence on the internal strength of the soil structure.