bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sr-Nd Isotope Composition of Uraniferous Leucogranites in the Gaudeanmus area, Central Damara Belt, Namibia
Authors: Chen Jinyong , Fan Honghai , Wang Shengyun , Gu Dazhao 
Published: June 2021

Abstract
The leucogranite-hosted uranium deposit in Namibia is a well-known intrusive uranium deposit in the world. In this paper, a systematic study of Sr-Nd isotopes has been carried out on uranium mineralized leucogranites in the Gaudeanmus area, Namibia. The results show that uranium bearing leucogranites were formed in the post-orogenic extensional environment, the εNd(t) values of the rock are from -13.5 to -17.4, with the initial 87Sr/86Sr ratios of 0.73035 ∼ 0.79345; and the ages of two-stage Nd model are between 2.32 ∼ 2.63 Ga. The Sr-Nd isotopic geochemical results of the pre-Damara basement, Damara sequence and uraniferous leucogranites indicate that the contribution of uranium rich pre-Damara basement to the ore-forming materials is dominant during the main metallogenic epoch of magmatic crystallization differentiation, while the extra uranium mineralization at the later hydrothermal stage may be from the primary uranium minerals such as uranite and coffinite.
Study on diagenesis and diagenetic evolution of reservoir in Wuerxun depression
Authors: Peng Wei , Zhou Yue 
Published: June 2021

Abstract
Wuerxun depression is one of the main oil-bearing depressions in the middle of the Hailar District Basin with high exploration degree. With the deepening of exploration degree, the pore structure and distribution law of tight reservoir in trough are not clear. In this paper, through the combination of quantitative and qualitative, micro and macro, following the idea of “phenomenon characterization, essence exploration, law summary”, the diagenesis analysis and diagenetic evolution of tight reservoirs are studied to find areas with relatively good reservoir properties in the depression, which provides theoretical basis for tight reservoir exploration. Diagenesis controls the formation, evolution and distribution of the reservoir. The diagenesis of the reservoir in this area mainly includes compaction, cementation and dissolution, thus forming five kinds of secondary dissolution pores (intergranular dissolution pore, feldspar and debris dissolution pore, mold pore, interstitial dissolution pore and dissolution fracture). Vertically, the physical properties of the reservoir are generally poor, but the reservoir is well developed locally. The reservoir is well developed at 1300-1900m and 2300-2700m in Wuerxun depression.
Study on the Factors Affecting the Design of Deep Backfill Foundation Pit and the Factors Affecting Soil Construction Disturbance
Authors: Yu-Chen JI , Jun Ao , Bin Wang , Jian-Dong Niu 
Published: June 2021

Abstract
Water is an indirect construction disturbance factor, which has important influence on the stability evaluation and analysis of foundation pit slope engineering. The study is mainly aimed at the deep backfill, the mechanical parameters are not uniform, and the effect of water on its mechanical parameters is great. The mechanical parameters of the backfill under different moisture content were measured by static triaxial shear test. The results show that the cohesion, internal friction angle and shear strength of the backfill are attenuated with the raise of the water content, the cohesion and internal friction angle of the attenuation law showed a linear re-gentle trend, and the shear strength of the decay trend gradually slowed down. The simulation results show that the mechanical parameters of backfill are reduced with the increasing number of saturation-dehydration cycles. The first degree of decay is the most significant, and finally tends to a certain value. The connection between the deterioration coefficient and the cycles follows the negative exponential function, and the mathematical expression of water deterioration was obtained finally. The study analyzes the damage mechanism of water in the construction disturbance, which has some theoretical support for the stability evaluation and disaster mitigation of the foundation pit.
Hydrophobic Modification of a Slag-based Geopolymer Coating
Authors: Zhu Chunyan , Guo Yaoxiang , Wen Zhiwen , Zhou Yu , Zhang Liangwei , Wang Zhihan , Fang Yuan , Long Wujian 
Published: June 2021

Abstract
The durability of geopolymer coatings is significantly influenced by water infiltration. In order to reduce the ingress of water, a slag-based geopolymer was modified respectively using methylsilicone oil (MSO) and organic silicon agent (OSO). For the characterization of the surface interaction between geopolymer and liquid, the contact angle, surface energy and critical surface energy of geopolymer were measured by a novel and accurate bubble method. Results show that surface hydrophobic modification of geopolymer is completely achieved by MSO modifier due to the increasing contact angle on the surface of geopolymer and the surface energy of geopolymer decrease to a certain extent. The critical surface energy curve is not only can describe wetting performance of the geopolymer, but also can predict the wetting feature of a specific liquid on the surface of the geopolymer intuitively and quickly.
Construction Characteristics and Design Strategy of the “Constant-holistic Shadow” in Mountainous Urban Area in Hot Summer Zone
Authors: Liu Yingqi , Gong Zhaoxian , Luo Guohui , Li Yinan 
Published: June 2021

Abstract
The sunlight in summer is generally strong in hot summer zone, so the long-lasting shadow is conducive to people’s outdoor activities for a long time. Creating a space with “Constant-holistic Shadow” has become an important way to improve the outdoor thermal comfort. However, with special shadowing condition featuring in a varied topography with big vertical height, the sunshine shadowing formation in mountainous urban area is significantly different from that of plain area. Therefore, it is necessary to take the special shadowing conditions into consideration in exploring the influence and relevance on the “Constant-holistic Shadow” construction. This paper analyzed the characteristics of outdoor spatial morphology and shadow forming elements in mountainous urban areas, revealed the correlation between the characteristics and “Constant-holistic Shadow” space, and expounded the main design strategies of “Constant-holistic Shadow” space in mountainous urban areas so as to provide ideas and strategic guidance for more effective construction of “Constant-holistic Shadow” space in mountainous urban areas.
Physical model test study on the working performance of integrated foundation pit supporting structure
Authors: Liu Zhan-Bo , Ren Jin-Ming , Li Shu-Yi , Wang Jun-Jie 
Published: June 2021

Abstract
The integration of underground single structure and retaining structure is a new type of foundation pit support, and its working performance needs to be further studied. The physical model test was carried out on the diaphragm wall structure of “two walls in one” in this paper. The soil settlement and the earth pressure of the outside of the foundation pit and the stress of the integrated supporting structure were analyzed when the excavation depth is different. The analysis showed that the settlement of soil behind the wall gradually increased with the increase of excavation depth of the foundation pit. when it was 1H

e
away from the diaphragm wall, the maximum of soil settlement occurred, which was 0.08%H

e
(H

e
is the maximum excavation depth). With the increase of excavation depth, the state changed from static to active. Under the same condition, the bending moment of the wall increased first and then decreased with the depth. The reverse bending point is near 1.23H

e
.
Study on the influence of tectonism on bauxite mineralization and exploration: a case study of the Luoyang Yellow River Basin, China
Authors: Sun Fengyu , Zhou Qikai , Cao Gaoshe 
Published: June 2021

Abstract
With the increasing demand for mineral resources, the exploration work needs to be strengthened, and the factors affecting the layout of exploration projects need to be further studied. In this paper, the bauxite deposits in the Luoyang Yellow River Basin, Western Henan, are the research objects. According to the geological background and mining characteristics, the influence of tectonism on bauxite mineralization and exploration is comprehensively analyzed. The comprehensive exploration methods (such as geology analysis, drilling engineering, geophysical prospecting, and testing) are used to evaluate the metallogenic prospect of the study area. Through field practice, good prospecting results have been achieved.
Hydration Heat Analysis and Temperature Control on Steel Shell Concrete Immersed Tube during Precasting
Authors: Sun Wenhuo , Liu Meimei , Ji Ting 
Published: June 2021

Abstract
In order to support the high-precision and high-quality prefabrication of steel shell concrete immersed tube for Shenzhen-Zhongshan Bridge, this paper analyzes the influence of temperature field produced by concrete hydration heat on the deformation and local stress of steel shell concrete immersed tube considering the influence of strength time-varying, autogenous shrinkage and creep of concrete and casting technology. Then, this paper puts forward the temperature control index of concrete molding based on the control requirements deformation and local stress of immersed tube. The results show that: the hydration heat of concrete is beneficial to the deformation control of steel shell concrete immersed tube, and it has little influence on the final deformation, the molding temperature of concrete should be controlled below 3°C of the ambient temperature to prevent the cracking of steel concrete interface of immersed tube. The research results of this paper have been applied to the control of concrete casting process of steel shell concrete immersed tube for Shenzhen-Zhongshan Bridge, which can make up for the domestic research blank and provide technical reference for similar projects.
Simulation And Prediction Of the Safety Risk Of Tower Crane For Super High-rise Buildings Through Back Propagation Neural Network
Authors: Lin Nan 
Published: June 2021

Abstract
High-rise buildings especially super high-rise buildings are booming with the rapid urbanization because the urban population increases dramatically. For the sustainable development of super high-rise buildings, construction safety is an important issue. Since tower cranes are widely applied on the construction of super high-rise buildings as the lifting and transportation equipment, their safety is closely related to the safety of construction sites. In this study, a reasonable safety evaluation system with clear input and output indicators was first established. Then, the input index was quantified, and their weights were determined according to their importance which were ranked based on the fourth-class division method of safety grade. Subsequently, the neural network model was developed. 90 tower crane accidents were evaluated quantitatively which provided the data to train and verify the model. The results show that prediction of neural network model is reliable. The trained neural network model is capable to predict the tower crane risks of high-rise buildings, which can be helpful to the construction safety management.
Effect of MnO2 and Li2CO3 on Compressive Strength and Thermal Conductivity of Aerated Concrete
Authors: Wei Pengfei , Yin Guansheng , Shi Minghui , Zhang Jintao , Yang Zhaotong , Feng Junjie 
Published: June 2021

Abstract
This study aims to evaluate the effects of catalyst (MnO2) and coagulant (Li2CO3) on the properties of aerated concrete consist of Portland cement, aluminate cement, and grade I fly ash by the chemical foaming method. In this experimental investigation, the compressive strength and thermal conductivity of aerated concrete were tested by more than 70 aerated concrete specimens with catalyst ranging from 0 to 2.0% and coagulant ranging from 0 to 4.0%. The results indicated that catalyst had a positive effect on the foaming efficiency when the foaming agent percentage is 4%. The positive impact reaches the peak when the catalyst percentage on 0.4%. Outcomes show that the compressive strength of aerated concrete decreases slowly with the increase of coagulant content. Still, the thermal conductivity decreases significantly due to the pore size of the foam increases. The study also reveals that the coagulant effect on ordinary Portland cement concrete setting is not apparent.
Seismic performance analysis of new frame columns in a story-adding frame structure
Authors: Shao Zhuhai , Xu Xinsheng , Wang Ning 
Published: June 2021

Abstract
With the rapid development of urbanization in China, the old urban buildings in many cities are facing the problem of weakening function. There are broad prospects for floor-adding renovation and expansion of in-service houses. In this paper, based on the background of the actual project, the direct floor-adding scheme is adopted to design the existing buildings after the reliability evaluation. The key point of the floor-adding reconstruction and expansion is whether the new part can be reliably connected with the old structure. In view of this weak link, this paper makes a further study on the seismic performance of new frame column members with different anchorage depth, which provides a certain guiding significance for the design and construction of story-adding reconstruction and expansion.
Experimental Study on Quasi-Static Energy Absorption Characteristics of Foam Concrete with Different Design Density by Hydroxypropyl Methyl Cellulose
Authors: Shi Minghui , Yin Guansheng , Wei Pengfei , Zhang Jintao , Yang Zhaotong 
Published: June 2021

Abstract
The foam concrete test blocks with different design densities were prepared. Different dosages of hydroxypropyl methylcellulose on the quasi-static energy absorption characteristics of foam concrete were studied through comparative experiments. The results show that the foam nominal load-displacement curve can be divided into three stages: elastic compression stage, plateau stage, and a densification stage. The higher the density of the foam concrete, the higher the initial peak load, the more outstanding the load fluctuation, and the worse the protective performance. The smaller the density, the longer the compression platform stage. 0.06% of HPMC improves the energy absorption characteristics of foam concrete with different densities the most, and the smaller the density, the greater the improvement ratio.
Design and Application of Mechanized Construction Equipment in Shallow Excavation Precast Utility Tunnel
Authors: Qian Kong , Rui Yang 
Published: June 2021

Abstract
Traditional open-cut method for utility tunnel has many disadvantages such as long-term occupation and large area of land, great disturbance to urban traffic and environment, high labour intensity of workers and so on. In order to overcome the disadvantages above, a machine for prefabricated utility tunnel construction was designed which drawing on the working principle of shield machine and pipe jacking machine. The above-machine is applied in shulong road utility tunnel of Chengdu. The applicable results show that: (1) The above-machine achieve movable streamlined synchronous construction of earth excavation, components assembling and earth backfill. It improve the shortcoming of traditional open cut method and cancel the majority of foundation pit bracing structure. (2) The above-machine can make mechanized and assemblage construction of shallow excavation precast utility tunnel come true. It effectively control construction quality and reduce difficulty of construction management.
Research on Construction Method of Self-Compacting Concrete with Machine-Made Sand
Authors: Zhang Yankun , Qian Dongya , He Shiqin , Zhang Zhuoran , Cai Guangzhi 
Published: June 2021

Abstract
Machine-made sand self-compacting concrete is a kind of self compacting concrete with machine-made sand as fine aggregate, which could fill formwork only by its own gravity, without concrete vibration. It is different from ordinary concrete in many aspects, such as fluidity, workability, and configuration method[1]. As a new type of concrete material, machine-made sand self-compacting concrete mix ratio has been studied in depth by many scholars. However, there are relatively few researches on the practical application of machine-made sand self-compacting concrete, especially on construction methods. This paper discusses the characteristics and construction differences between machine-made sand self-compacting concrete and ordinary concrete, and proposes a special construction method for machine-made sand self-compacting concrete.
Research on Geotechnical Investigation and Construction Technology of Construction Engineering
Authors: Yang Lipeng 
Published: June 2021

Abstract
This article mainly analyzes the technical practice of construction engineering geotechnical survey and construction treatment. This project describes the practical significance of geotechnical engineering survey for construction engineering. It analyzes the surveying techniques commonly used in current geotechnical surveys, such as geological surveys, surveying and mapping, and prospecting. Take a construction project as an example to illustrate the application of engineering geotechnical survey and processing technology. This study can provide reference and reference for construction engineering geotechnical survey work.
Analysis of seismic performance of assembled steel structure staggered truss system
Authors: Liu Qin , Liao Tingzhou , Peng Xi , Xu Shuang 
Published: June 2021

AbstractIn order to adapt to the application and development of large-span steel structure, this paper takes a 19-story assembled hybrid staggered truss structure office building as the background. SAP2000 finite element analysis software is used to establish two different forms of assembled steel structure staggered truss system, namely the hybrid staggered truss structure and the vierendeel staggered truss structure. The seismic performance of the structure was analyzed by modal analysis and dynamic elastic-plastic time-history analysis. The main conclusions are as follows: According to the modal analysis of the structure, the directions of the first three modes of the hybrid staggered truss structure are different from those of the vierendeel staggered truss structure. However, the natural vibration period of the two structures gradually decreases with the increase of the vibration mode. The natural vibration period of the vierendeel staggered truss structure is obviously larger than that of the hybrid staggered truss structure, which indicates that the stiffness and quality of the hybrid staggered truss structure are both larger than that of the vierendeel staggered truss structure. Through the dynamic elastic-plastic time-history analysis of the structure, the seismic performance of the two staggered truss structures in the X direction is basically the same. The difference is mainly reflected in the seismic performance in the Y direction. The seismic performance of the hybrid staggered truss structure is obviously better than that of the vierendeel staggered truss structure.
Research on Mechanical Properties of Typical Bracket Set in Traditional Timber Buildings of Song and Yuan Dynasties in Jiangnan Region
Authors: Xiaohu Jia , Qing Chun 
Published: June 2021

Abstract
The bracket set of traditional Chinese timber buildings in Jiangnan region plays a structural and decorative role. The research of it is of great significance for cognitive the characteristics of local traditional timber buildings. In order to further understanding the mechanical properties of typical bracket set in traditional timber buildings of Song and Yuan dynasties in Jiangnan region, the methods of field investigation and numerical simulation were used. The typical bracket set of traditional timber buildings of Song and Yuan dynasties were extracted. The construction practices, mechanical properties and importance of components were studied. The results provide a basis for conservation of bracket set effectively and scientifically.
The effect of the force between rings of large-diameter shield tunnels on the segmental cracking in weak stratum
Authors: Han Xiaoming , He Chuangbo , Xu Chao , Zhong Han , Zhang Feilei 
Published: June 2021

Abstract
Large-diameter shield tunneling in weak strata has the risks of segment floating, segment cracking and seepage, affecting the durability of the tunnel structure. In this paper, the statistical analysis of the cracks of a large-diameter shield tunnel segment was carried out, and the thickness of the force transmission liner was studied. The experiment showed that the average number of cracks per ring was the smallest when using a 3mm liner. Based on the structural characteristics of the segment, four types of stresses, namely simple support of segment boss, double-sided cantilever, single-point cantilever and two-point cantilever, and it is verified through on-site statistics, which has certain guiding significance for crack prevention.
Development of an automatic measurement device for double laser shield tail gap based on image recognition technology
Authors: He Chuangbo , Xu Chao , Xiong Dongdong 
Published: June 2021

Abstract
Shield tail clearance is an important basis for the selection of segment assembly and shield attitude control. It is the most direct factor affecting shield tail brush wear. Poor shield tail clearance is prone to segment damage and shield tail seal failure. Using manual measurement of the shield tail gap, the measurement data has a certain hysteresis, and can not directly reflect the changing trend of the shield tail gap. Based on image recognition technology, a dual laser shield tail gap measurement device was developed to measure the changes in the shield tail gap during shield tunneling. The field test shows that: 1 The measurement device can monitor the shield tail gap in real time, and can simulate the ellipticity of the shield tail, monitor the deformation of the shield tail and the space state of the shield tail and the tube. 2 The acquisition device adopts a dual laser transmitter, meanwhile, the attitude of the shield machine cannot be controlled in real time, Can accurately establish the geometric relationship between the actual distance and the pixel distance, improve the test accuracy of the measuring device, and control the monitoring accuracy at 3.8 mm.