bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysis method of big data based on K-means algorithm
Authors: Zhang Yichi , Shu Tao , Zhang Pengxiang , Xu Yan
Published: June 2021

Efficient and accurate clustering of massive data is the basic requirement of deep excavation for internal knowledge of data in the information era. Firstly, in the distributed parallel processing framework of Hadoop, the Map Reduce model is applied to operate the K-means clustering algorithm, then the genetic algorithm is utilized to transform the clustering problem of K-means algorithm into the solution of extremum to solve the randomness confirmed in cluster center. After testing, this method has achieved the ideal effect in terms of clustering efficiency and clustering precision, and plays certain role in deeply excavating the internal knowledge rule of data.
Application of CNC Boring Machine in Connecting rod Screw Hole Machining
Authors: Huang Wen
Published: June 2021

This paper expounds the shortcomings of the traditional drilling, expanding and reaming processing processing methods of connecting rod screw holes, and proposes a new technology for processing connecting rod screw holes using a special CNC boring machine. Then, this paper introduces the process method of CNC boring machine processing connecting rod screw hole and the design of tooling fixture, and through the example of programming and processing, it’s proved that the new technology greatly improves the quality of screw hole. While reducinges the labor intensity of workers and improving the production efficiency, it also creates good economic and social benefits.
Application of Controlled Blasting in Urban Complex Environment Foundation Excavation
Authors: Zeng Cheng-Li , Liu Guo-Jun , Zhang Hai-Long
Published: June 2021

In the city buildings, dense area blasting to excavate mass rock belongs to the controlled blasting of stonework in complicated situations. In order to reduce the impact of blasting vibration on the surrounding environment, it is necessary to take a variety of blasting technology combined with the construction scheme. Lanzhou Ming Cheng Plaza foundation excavation uses millisecond short-hole blasting technology, by taking measures of choosing the reasonable digging groove position and control maximum charge weight per delay interval, achieved the purpose of control flying rock and reduce the blasting vibration.
Design and Control Method of Power-Cycling Variable Transmission System
Authors: Sun Dongye , Wenfeng Hou , Junren Shi , Yingzhe Kan
Published: June 2021

A design theory of a power-cycling variable transmission (PCVT) system with improved transmission efficiency and continuously variable transmission characteristics was proposed for preserving the characteristics of transmission types such as the friction, hydrodynamic, and hydraulic drives. This study expounds on the structure and working principle of PCVT, analyzes its main characteristics, and describes its unique performance through a series of design examples.
Design and Experimental Verification of a Multirotor Aircraft with fuzzy neural network controller
Authors: Di LI , Kun Shu
Published: June 2021

Conventional multirotor aircrafts are underactuated, while the translational and rotational motions are strongly coupled. These features severely limit the maneuverability of the aircraft. Therefore, a multi-rotor aircraft is designed, which can perform omnidirectional motion, vector thrust control flight and tilt-hovering. In addition, an fuzzy nerual network controller is designed. And the aircraft demonstrates a higher fault tolerance than the conventional ones. Finally, the experimental results show that the aircraft has a higher maneuverability than the conventional quadrotors.
Fault Diagnosis Method for Certain Equipment Based on Case-based Reasoning
Authors: Junjie Hao , Hongni Gao , Wei Wang , XinCheng Song , Dayan Wang , Qinsheng Jiang
Published: June 2021

Absrtact: With the increasing complexity, information and intelligence of combat systems and weapons equipment, the traditional fault diagnosis technology can not meet the requirements of rapid and accurate fault diagnosis of equipment. In this paper, according to the fault characteristics and maintenance status of a certain type of equipment, combined with case-based reasoning technology, an equipment maintenance system which can realize intelligent query, case accumulation and fault reasoning is proposed. Finally, the feasibility of the method is proved by an example.
Flexible Flow Shop Scheduling and Energy Saving Optimization Strategy under Low Carbon Target
Authors: Yin Ruixue , Li Chaowen , Feng Xuqing , Yang Qingbin
Published: June 2021

In order to reduce the carbon emissions of the flow shop which consists of unrelated parallel machine, a kind of scheduling mathematical mode with low carbon emission target is built by analyzing the carbon emissions of the machine tools under different running conditions. Not only the carbon emissions produced in the handling process which is rarely discussed in the previous studies, but also the carbon emissions produced during the start-up and shutdown process of the selected machine tools are considered in the model. Based on this model, a multi-state alternation energy saving optimization strategy is proposed to reduce carbon emissions during the idle waiting period of machine tools. An improved genetic algorithm is employed to solve this optimization problem. In the end, the t cases are studied to validate the strategy.
Progress on different topology optimization approaches and optimization for additive manufacturing: a review
Authors: Zhan Tianxia
Published: June 2021

The progress of topology optimizations for the last decade has been reviewed based on the five main methods mentioned in Sigmund’s article in 2013: density, level-set, topological derivative, phase field, and evolutionary. The recent progress is mainly focusing on methods originated in density or level set method, with an inclination of combining them with the evolutionary method. The methods developed have a large number of applications, yet certain issues, e. g., guaranteeing the convergence of the results generated through evolutionary methods need further investigation. Besides, those studies specifically targeted for the optimization and designing for additive manufacturing are also discussed, as well as the ideas and guidelines for those designs. It is recognized that in order to cope with additive manufacturing, it is necessary to modify existing structures for the application of lattice structures and the reduction of support structures. Moreover, the introduction of the idea of designing for additive manufacturing (DfAM), as well as efforts to make the end-users understand and familiarize themselves with the dramatic differences in designs, are also desired changes that need more efforts to be applied on.
Research on Beamforming Algorithm of Millimeter Wave System Based on Mobility of Network Vehicles
Authors: Qinghua Zhu , Ying Chang , Junfeng Shi , Jingya Zhao , Yong Liu
Published: June 2021

During the operation of mobile networked intelligent vehicles, beamforming training is often needed, which will lead to a significant increase in training time and adverse impact on system performance. This paper analyses this problem in detail, and establishes a new beamforming algorithm, that is, to predict the position and state information of the vehicle in the process of movement, and then beamforming based on the results obtained; the predicted vehicle position results have errors, so we need to reduce the position error as much as possible, calculate the optimal beamforming width, and significantly improve the system performance. The simulation results show that the performance of the beamforming algorithm proposed in this paper is significantly improved compared with IEEE 802.11ad, which can meet the requirements of practical application.
Research on power and vibration signal acquisition method and system of machine tool for tool wear monitoring
Authors: Zhou Bo , Zhang Jianfu , Fu Yongkang , Yu Dingwen , Wang Jianjian
Published: June 2021

Tool wear state is a crucial factor in the process of machine tool processing. Tool wear and failure affects the processing quality. Tool replacement in advance affects the production efficiency and increase the production cost. During the machining process, the power and vibration signal often change with the increase of tool wear, which provides a way to monitor tool wear. To meet the needs of tool wear monitoring, this paper presents a system architecture and hardware composition of power and vibration signal acquisition of machine tool, and develops a system to synchronously collect power, vibration signal and process parameters of machine tool. The vibration and power characteristic information recognition method is then discussed corresponding to the process to be monitored from the collected signals. The experimental results show that the system is able to collect and screen the changes of power and vibration signal throughout the whole life cycle of the cutting tool in real-time. The feature information recognition and screening have high efficiency and accuracy, which provides a data basis for tool wear monitoring.
A 12-bit 30 MS/s SAR ADC in 180 nm CMOS for PMT signal readout
Authors: Guo Y. , Zhou S. , Zhao L. , Qin J. , Yang Y. , Xuan D. , Song C. , Liu S. , An Q.
Published: June 2021

Photomultiplier Tubes (PMTs) are widely used as the photon
detector in high energy physics experiments for their fast response
and high sensitivity. High precision charge measurement is usually
required for PMT readout, and especially in cosmic ray experiments a
large dynamic range is also demanded. This paper describes an
Analog-to-Digital Converter (ADC) Application Specific Integrated
Circuit (ASIC), which aims to work with a front-end analog ASIC to
perform charge measurement based on the digital peak detection
method. This ADC design is based on the power-efficient Successive
Approximation Register (SAR) architecture, to achieve a 12-bit
resolution with a sampling rate of up to 30 MS/s. Test results
indicate that the Effective Number of Bits (ENOB) of this ADC is
better than 9.2 bits with a sampling rate of 30 MS/s.
A multidimensional feasibility evaluation of low-carbon scenarios
Authors: Brutschin Elina , Pianta Silvia , Tavoni Massimo , Riahi Keywan , Bosetti Valentina , Marangoni Giacomo , van Ruijven Bas J
Published: June 2021

Long-term mitigation scenarios developed by integrated assessment models underpin major aspects of recent IPCC reports and have been critical to identify the system transformations that are required to meet stringent climate goals. However, they have been criticized for proposing pathways that may prove challenging to implement in the real world and for failing to capture the social and institutional challenges of the transition. There is a growing interest to assess the feasibility of these scenarios, but past research has mostly focused on theoretical considerations. This paper proposes a novel and versatile multidimensional framework that allows evaluating and comparing decarbonization pathways by systematically quantifying feasibility concerns across geophysical, technological, economic, socio-cultural and institutional dimensions. This framework enables to assess the timing, disruptiveness and scale of feasibility concerns, and to identify trade-offs across different feasibility dimensions. As a first implementation of the proposed framework, we map the feasibility concerns of the IPCC 1.5 °C Special Report scenarios. We select 24 quantitative indicators and propose feasibility thresholds based on insights from an extensive analysis of the literature and empirical data. Our framework is, however, flexible and allows evaluations based on different thresholds or aggregation rules. Our analyses show that institutional constraints, which are often not accounted for in scenarios, are key drivers of feasibility concerns. Moreover, we identify a clear intertemporal trade-off, with early mitigation being more disruptive but preventing higher and persistent feasibility concerns produced by postponed mitigation action later in the century.
Estimating integrated measures of forage quality for herbivores by fusing optical and structural remote sensing data
Authors: Jennewein J S , Eitel J U H , Joly K , Long R A , Maguire A J , Vierling L A , Weygint W
Published: June 2021

Northern herbivore ranges are expanding in response to a warming climate. Forage quality also influences herbivore distributions, but less is known about the effects of climate change on plant biochemical properties. Remote sensing could enable landscape-scale estimations of forage quality, which is of interest to wildlife managers. Despite the importance of integrated forage quality metrics like digestible protein (DP) and digestible dry matter (DDM), few studies investigate remote sensing approaches to estimate these characteristics. We evaluated how well DP and DDM could be estimated using hyperspectral remote sensing and assessed whether incorporating shrub structural metrics affected by browsing would improve our ability to predict DP and DDM. We collected canopy-level spectra, destructive-vegetation samples, and flew unoccupied aerial vehicles (UAVs) in willow (Salix spp.) dominated areas in north central Alaska in July 2019. We derived vegetation canopy structural metrics from 3D point cloud data obtained from UAV imagery using structure-from-motion photogrammetry. The best performing model for DP included a spectral vegetation index (SVI) that used a red-edge and shortwave infrared band, and shrub height variability (hvar; Nagelkerke R
2 = 0.81, root mean square error RMSE = 1.42%, cross validation ρ = 0.88). DDM’s best model included a SVI with a blue and a red band, the normalized difference red-edge index, and hvar (adjusted R
2 = 0.73, RMSE = 4.16%, cross validation ρ = 0.80). Results from our study demonstrate that integrated forage quality metrics may be successfully quantified using hyperspectral remote sensing data, and that models based on those data may be improved by incorporating additional shrub structural metrics such as height variability. Modern airborne sensor platforms such as Goddard’s LiDAR, Hyperspectral & Thermal Imager provide opportunities to fuse data streams from both structural and optical data, which may enhance our ability to estimate and scale important foliar properties.
Forested lands dominate drinking water supply in the conterminous United States
Authors: Liu Ning , Caldwell Peter V , Dobbs G Rebecca , Miniat Chelcy Ford , Bolstad Paul V , Nelson Stacy A C , Sun Ge
Published: June 2021

Forests provide the most stable and highest quality water supplies among all land uses. Quantitatively evaluating the benefits of forest water supply functions is important to effectively mitigate the impacts of land development, climate change, and population growth. Here, by integrating a water balance model and national drinking water data, we determined the amount of surface water yield originating on different forest ownership types at a fine resolution (88,000 watersheds) and tracked that water through the river network to drinking water intakes and the populations they serve. We found that forested lands comprised 36% of the total land area but contributed 50% of the total surface water yield. Of the 23,983 public surface drinking water intakes depending on surface water sources, 89% (serving around 150 million people) received some (>0.01%) surface water from forested lands, and 38% (serving about 60 million people) received more than 50% of their surface drinking water supply from forested lands. Privately-owned forests were the most important water source in the eastern U.S., benefiting 16 million people, followed by federal forests (14.4% of the total water supply). In contrast, federally-owned forested lands were the dominant water source (52% of the total water supply) in the West. Privately-owned forests are the most vulnerable to future land use change and associated water supply impacts. Continuing programs that support private forest landowners with financial and technical assistance through federal and state forest management agencies and potentially developing payment for ecosystem service schemes could maximize benefits for landowners so they may retain their land assets while minimizing forest loss and associated impacts on critical ecosystem services including the provisioning a clean and reliable water supply for the American public.
Study on slope stability during tunnel construction in water rich soft soil area
Authors: Xiong Qihuan , Yuan Qing , Shen Jiuzhou , Yang Lin , Cheng Shihao , Zhang Ziping
Published: June 2021

Based on the relationship between soil strength index and water content, the stability of tunnel portal slope during tunnel excavation in water rich soft soil area is analyzed according to the change of soil water content under different working conditions during tunnel construction. The results show that the strength index of soil decreases in inverse proportion with the increase of saturation. Reasonable excavation speed or effective dewatering measures are conducive to the self stability of the open cut slope. When the duration of heavy rainfall does not exceed 2 h, the slope is in a stable state; when the duration reaches 10 h, the slope enters the limit equilibrium state; when the duration reaches 18 h, the slope enters the failure state.
Research on the Optimal Clearance Distance of Super-Large-Diameter Shield Tunnel Underpassing the Existing Metro Tunnel
Authors: Liu Nian
Published: June 2021

With the accelerating urbanization in China and the constant development of underground space, shield tunnels have been extensively applied to underground roads in central urban areas. However, the central areas are featured with complex surroundings, such as numerous subways, bridge pile foundations, basements, pipelines, and other structures and buildings. Therefore, it will be an unavoidable engineering difficulty for the construction of shield tunnel in the central urban area to cross at a close range buildings (structures) such as existing tunnels, underground pipelines, underground passages and basements. At present, there are remarkable research results for the crossing of subway shield tunnel with an outside diameter of 6.0 m, and rich research results for the crossing of shield tunnel with an outside diameter of 10-14 m. However, there are relatively few studies on the shield tunnel with an outer diameter of 15 m and above crossing existing buildings (structures). Based on Shanghai Beiheng super-large-diameter shield tunnel (outside diameter 15.0 m), the Midas_GTS finite element analysis software was used herein to study the relation between the underpassing clearance distance h and the peak settlement of existing metro tunnel S. The optimal clearance distance of the super-large-diameter shield tunnel underpassing the existing metro tunnel in the soft soil area h was drawn to be 7.0∼8.0 m. Through analysis, it was found that the ground loss rate ρ and the tunnel peak settlement S of the existing tunnel was linear, with the slope = 2.795 > 1. It proved that the tunnel peak settlement S of the existing tunnel was significantly influenced by the ground loss rate ρ. Therefore, it’ s quite reasonable to take the ground loss rate ρ as the evaluation indicator and control requirement for crossing construction.
Analysis of Measures to Strengthen the Safety of Civil Engineering Structure Design
Authors: Zhang Lingmei
Published: June 2021

This article analyzes the relevant content of the safety design of civil engineering structures. This paper studies the common problems in the safety design of civil engineering structures, including design methods to be optimized, relatively low training efforts, relatively poor innovation capabilities, more construction safety hazards, unreasonable internal force combination design, and low safety supervision. The author studied how to optimize structural design methods, how to strengthen personnel training, how to deal with system innovation, how to strictly control building conditions, how to optimize the design of internal forces, and how to strengthen safety supervision. The purpose of this article is to improve the level of civil engineering structural design and improve the construction quality of construction projects.
Tourmaline geochemistry and boron isotope variations as a guide to fluid-rock interaction in the Qinghe pegmatite, NW China
Authors: Zheng Beiqi
Published: June 2021

The alteration zone around pegmatites can be used as a direct tool to trace the property of pegmatite-derived fluids. In the present study, EPMA, LA-ICP-MS, and MC-ICP-MS were used to analyze major elements, trace elements and boron isotope compositions of tourmaline from Qinghe barren pegmatite, NW China. Most tourmalines from the pegmatite are schorl, while the remaining tourmalines from the pegmatite, the contact zone, the altered wall rock and the unaltered wall rock are dravite. All tourmalines follow the exchange vector (Fe + Mg) (Al + Xvac)−1, indicating enriched Fe and Mg. The Fe3+Al−1 exchange vector and increase of V/Sc in the late stage suggest sudden destruction of the pegmatite system. The δ11B indicates that a small scale fluid exsolution occurred in the late stage. Compared with other fertile pegmatites around the world, Qinghe pegmatite has the most negative δ11B and lower Li content, indicating that both the source and evolution process have an impact thereon.
Experimental Study on Zoning Characteristics of Soft Soil Blasting Disturbance in Sea Embankment Foundation
Authors: Xiao Xian-Bo , Xu Jian-Zhang , Xu Xue-Yong
Published: June 2021

The current research on the mechanism of blasting compaction mainly focuses on how to form a rockfill dam under the action of blasting load, but there is little research on the dynamic response characteristics of soft soil media under blasting. In blasting compaction of deep silt, it is necessary to pay attention to the damage and disturbance effect of explosive explosion on the surrounding soft soil medium, thereby providing new ideas for the study of blasting compaction mechanism of deep silt. With a seawall project in Huizhou as a prototype, based on the blasting similarity theory and through a generalized model and parameter similar design, experimental research on deep silt blasting compaction centrifuge was carried out in a 200g-t centrifuge. The physical and mechanical parameters of the silt soft soil at different positions were acquired through testing before and after the blasting, and property changes of the soft soil medium were analysed under the explosion to speculate disturbance range of the soft soil medium under the explosion effect, and divide the different blasting disturbance areas. The test results provide data support for the optimization of the design parameters of the seawall project, and also provide a useful reference for the study on the blasting compaction mechanism of deep silt and similar engineering practices.
Experiment on Tension-compression Ratio of Hybrid Fibers Reinforced Recycled Aggregate Concrete
Authors: Feng Junjie , Yin Guansheng
Published: June 2021

The cubic compressive and splitting tensile strength of recycled aggregate concrete reinforced with hooked-end steel and macro-polypropylene hybrid fibers (HFRRAC) was investigated through an orthogonal experiment. The results show that the replacement ratio of RCA has little effect on the tension-compression ratio. And the volume percentages of HES fiber are the most significant influencing factor in terms of fibers. The specimens reinforced with fibers fail in a ductile manner and are enhanced in the energy absorption capacity. The proposed prediction models for cubic compressive and splitting tensile strength of HFRRAC are adopted to predict the experimental results and meet the engineering application accurately.
Research Progress on the Joint Connection Mode of Steel Coupling Beam
Authors: Zheng Xunzhen , Chen Jiguang , Jiang Haichuan
Published: June 2021

Coupling beam is an important component of seismic structure, the damage of coupling beams can consume earthquake energy, thereby protecting the safety of the structure. In order to ensure that the advantages of steel coupling beams are fully utilized, the joint connection form of steel coupling beams and structures has become the focus of many scholars’ research. This paper systematically summarizes the latest research progresses on the connection mode of joint with steel coupling beam, and their advantages and disadvantages are discussed, which provides a reference for engineering application.
Study on creep characteristics of residual soil in Central Yunnan Water Diversion Project
Authors: Li Chongyang , Zhang Qingwen
Published: June 2021

Sericite schist is an extremely soft rock. Most of the sericite schist residual soil in nature is in an unsaturated state, The matrix suction of the residual soil has a great influence on its strength. In this paper, an unsaturated quadruple consolidation tester and an unsaturated triaxial creep tester are used to carry out one-dimensional and three-axis creep tests on sericite schist residual soil. The test results show that the creep characteristics of the soil sample are obvious. Both the one-dimensional and triaxial tests show obvious three-stage characteristics. At the same time, the influence of the matrix suction and the net vertical stress on the creep characteristics of the soil is comparatively analyzed.
Resarch on Calculation Method of Pile Horizontal Response under Combined Loads
Authors: Li Yongzhi , Huang Wei , Ji Fuquan , Yang Minghui
Published: June 2021

The main function of the pile foundation is to bear the vertical load, but in actual engineering, the pile foundation usually bears combined loads which contain vertical load, lateral load and bending moment. Under combined loads, due to the P-Δ effect, the calculation of the bearing capacity and deformation of the pile foundation is very complicated. The small deformation superposition principle recommended by the current pile foundation codes fails to consider the resistance of the soil around the pile under the combined loads, and it is difficult to accurately evaluate the influence of P-Δ effect on the bearing capacity and deformation of pile foundation. In view of this, this paper firstly starts from the potential energy equation of the pile-soil system and deduces the calculation formula for the horizontal displacement of the pile considering the P-Δ effect, and it is verified in conjunction with related calculation examples. Then the factors affecting the P-Δ effect are discussed in detail, and the results show that the larger the load ratio is, the more obvious the P-Δ effect will be; when the pile top is fixed under the same load condition, the P-Δ effect will be significantly weakened.
Study on Surface Settlement Law of Shield Construction in Mudstone Stratum
Authors: Song Xiangshuai , Xiong Dongdong
Published: June 2021

In order to explore the influence of groundwater on the surface settlement law of shield construction under mudstone with different weathering degrees, this paper studies the influence of buried depth on surface settlement under different weathered mudstone, and the influence law of groundwater in stratum and different depths of water level on settlement of shield construction using a three-dimensional(3D) numerical model establish by finite element software based on the engineering background of Chengdu Metro Line 18. The results show that: (1) With the increase of buried depth, the range of lateral settlement trough on the surface gradually increases, but the maximum settlement gradually decreases. By analyzing the buried depth and the maximum surface settlement, it is found that the buried depth ratio has a logarithmic relationship with the corresponding maximum surface settlement. (2) The construction settlement increases obviously when there is groundwater in the stratum compared with when there is no groundwater. (3) The depth of water level above the vault and the maximum settlement caused by shield construction basically conform to the linear law. For every 1m increase in the depth of water level above the vault, the maximum settlement value can increase by about 0.43 mm. Compared with the field monitoring data, the calculation results are basically consistent, which shows the reliability of the calculation. This paper aims to provide experience for similar projects.
Mineralogical and mineral composition analysis of lacustrine sediments from Lake Toson, NE Qinghai-Tibet Plateau, China
Authors: Cheng Aiying , Yu Junqing , Gao Chunliang , Zhang Lisha
Published: June 2021

Mineralogy is very important in the study of lake, especially in the study of regional and past global change using lake sediments. In the final analysis, mineralogy could be involved in the study of the in-depth mechanism of lake sediments. In this paper, analysis the minerals by XRD in the sediments of Toson lake in the northeast of Qinghai-Tibet Plateau, the results showed that the main minerals in Toson lake were aragonite, calcite, quartz, halite, albite, muscovite, clinochlore and dolomite. And the main categories were detrital minerals and carbonate minerals with obvious reverse correlation. It suggested that Toson lake was mainly situated carbonate sedimentary stage, and the input of carbonate was lacustrine authigenic carbonate.
Analysis of influencing factors of passive building energy consumption in hot summer and cold winter area
Authors: He Chao , Wang Bojun , Yang Yanping , Jin Kai
Published: June 2021

Under the background of urbanization and the improvement of living standard, building energy consumption is increasing day by day and energy saving and consumption reduction in construction industry is imminent. As a new type of energy-saving healthy and livable building, passive building will inevitably become the development trend of future buildings. Based on the factors that affect the energy consumption of passive buildings in hot summer and cold winter areas, this paper finds out the main influencing indexes, calculates the accurate index weight by AHP and corrects it by entropy weight method in order to be more objective. Finally, the method is applied to an example and relevant suggestions are put forward based on the research results and the examples.
Research on earthquake damage mechanism of a subway station structure based on centrifuge shaking table tests and numerical analysis
Authors: Zhang Zihong , Xu Chengshun , Li Yang , Du Xiuli , Han Runbo
Published: June 2021

During the 1995 Kobe earthquake, the Daikai subway station witnessed serious collapse, which attracted the attention of people to the earthquake damage response of the subway structure. To study the earthquake failure mechanism of a subway station structure, two comparative dynamic centrifuge tests were performed. During the centrifuge tests, many important physical quantities cannot be directly monitored with appropriate instruments due to many limitations, such as extremely small model structures, extremely high collection frequency and complex centrifugal environment. To study the earthquake failure mechanism of a subway station structure in depth, an extended analysis of model tests was performed by means of numerical model. Finally, the earthquake failure mechanism was summarized in detail based on the numerical analysis.
Survey of Guoxia-Silaotou fault
Authors: Li Baolai , Zhang Hanliang , Ren Fengwen , Nie Dawei , Li Chunfeng
Published: June 2021

Guoxia-silaotuo fault is a part of Longxian-Baoji fault zone. In previous studies, people only inferred the spatial distribution of the fault from the indirect evidences of geomorphology and geophysics. In this paper, through the detailed investigation of the fault, the outcrop of the fault plane is found; the trenching method is used to investigate the fault, and the activity scale of the fault is revealed. It is found that in the late Pleistocene, the activity intensity of the fault is relatively high.
Treatment Technology of Closed Tunnel Filled with Water
Authors: Rao Weisheng , Li Dejie , Li Jiacheng , Feng Longjian
Published: June 2021

During the construction of No.3 connection gallery between huyong station and lvdaohu station of first phase project of Line 2 Foshan Rail Transit, water and sand kicks caused the large-scale settlement of tunnel segments. After comparison and selection of schemes, the rehabilitation scheme of abandoning the existing right line tunnel, shield machine starting from huyong station and heading to Lvdaohu Station by changing the line, is finally adopted. In order to prevent secondary disasters caused by the collapse of abandoned tunnels, the ground boreholes are used to fill the abandoned tunnels. During the construction, a series of key construction technologies have been formed, such as sectional backfill of abandoned tunnel, alternate backfill of underwater concrete and mortar, and prevention of pipe blockage. The results of core-drilling test and subsequent construction procedures show that the treatment scheme of abandoned tunnel is reliable and feasible, which can provide reference for similar projects.
Influence of retaining method of reservoir foundation pit on construction deformation of surrounding soil
Authors: Liu Zhanbo , Li Shuyi , Ren Jinming , Wang Junjie
Published: June 2021

In order to avoid the summer rainfall flood peak and improve the efficiency of rainwater utilization, many cities have put the construction of storage ponds on the agenda. However, the design of the foundation pit of the storage tank mostly adopts the design method of building foundation pit, that is, the foundation pit supporting structure will be dismantled after the main structure construction to a certain extent, so this has resulted in a greater waste of resources. In view of the above reasons, this paper proposes a economical foundation pit supporting structure of underground storage pond. This structure can be used as both retaining structure and pool body structure in the process of foundation pit excavation, which can reduce the waste of materials in the construction process and reduce the project cost. Through the calculation results of MIDAS-GTS software, it can be seen that the optimized structure has a good supporting effect in the process of foundation pit excavation, and can completely replace the temporary supporting structure in the original design scheme. The calculation results can provide reference for similar engineering construction.
Causes analysis of shield tunnel cracks in deep stratum with high water pressure
Authors: Tan Xiaofeng , Wen Bowei , Xu Chao , He Chuangbo , Xiong Dongdong , Song Xiangshuai
Published: June 2021

In the process of shield tunneling, there is a risk of cracks and diseases caused by geological changes, construction process, design and other factors, and leads to the construction process and even engineering accidents. This paper analyzes the cracks on the top of the segment under the geological conditions of deep burial and high water pressure by analyzing the cracks of a traffic rail project in Shenzhen, and analyzes the reasons for the cracks under normal construction. Based on the conventional stress model of segment and the screening of surrounding geological and hydrological conditions, the model assumption of local stress of integral segment is made, and the modified idiom and beam method are adopted- The results show that under the geological condition of fractured water stratum, the sudden change of water pressure caused by rainstorm and the joint action of broken rock block and segment floating will lead to the reduction of segment top space and direct contact with rock stratum, which will exceed the normal pressure range of segment and lead to cracks in the top segment.
Experimental research on geotechnical engineering characteristics of coral reef in Xisha Islands
Authors: Yang Yongkang , Yang Wu , Feng Chunyan
Published: June 2021

Coral reefs are widely distributed in Xisha Islands, which have special engineering properties. Coral reef geology from top to bottom is coral sand, coral gravel, coral reefs calcareous rock. Coral sand and coral gravel have the characteristics of mixed size particles, alternating accumulation of sand and gravel, great change of density and gradually coarsening from top to bottom. Coral reefs calcareous rocks are composed of loose bioclasts cemented, some of them are dense, and some of them are semi-cemented and weakly cemented. The geological age of the Xisha Islands within 50m was determined by carbon-14 radioisotope isotopic test. The bearing capacity and deformation characteristics of coral sand and coral gravel were analyzed by plate loading test, heavy dynamic penetration test, extra-heavy dynamic penetration test and standard penetration test. The physical and mechanical characteristics of coral reefs calcareous rock were studied by longitudinal wave velocity test, density test, porosity test and uniaxial compressive strength test.
Research on Construction Elevation Control of Wide-with Cable-Stayed Bridge with Low Pylon
Authors: Li Shuqin , Zhang Xuxin
Published: June 2021

Elevation monitoring is an important step in the construction process of wide low tower cable-stayed bridge. In this process, it mainly controls the difference between the actual elevation and the design elevation in the cantilever construction process of beam section, and controls the formwork elevation value of each section of beam section construction, In the study of cantilever construction elevation monitoring method, this paper analyzes the engineering background and elevation detection process error analysis, elevation control value selection and elevation linear control analysis, and takes a wide low tower cable-stayed bridge as an example, combined with the actual test results to verify the method. It is concluded that the elevation correction error is controllable and the construction alignment is consistent with the design alignment. The vertical alignment error meets the specification requirements, which can provide reference for the elevation control of similar projects.
Research on methods of investigation and analysis of highway slope stability after flood based on Insar and field investigation
Authors: Fan Jianbo , Xiong Xingbing , Peng Xi
Published: June 2021

The stability of highway slopes after floods is related to the smooth operation of traffic, construction and other related projects along the road. Taking highway slopes in Guizhou Province as the research object, conducting InSAR monitoring and on-site surveys on them, and obtaining a large amount of slope characteristic data after flood, the main conclusions are as follows: InSAR technology can study the influence of highway slope stability after flood, therefore, it saves a lot of manpower and time cost, uses on-site survey method to count the relevant characteristics of the slope along the highway, and uses the index system method to evaluate the risk level of the slope. It is believed that the road slope is prone to poor stability after the flood, and the risk level is higher.
Structure behavior of a fabricated shotcrete sandwich wall system under axial compression
Authors: Zhang Shoushuo , Xie Qun
Published: June 2021

A new type of fabricated shotcrete sandwich wall system is proposed. The wall system consisted of steel mesh, foamed concrete blocks, reinforced concrete layers, and core column. The shotcrete has been adopts in structural layer. Steel mesh is placed in the concrete layer. Foam concrete blocks are filled between concrete layers with function of insulation. Core columns are arranged along the cross section of wall with spacing 600mm. Prefabricated rebar cage place in core column. The finite element software ABAQUS is used to calculate its compressive strength, and the calculation results are compared with the theoretical method of related code. The results show that the FE simulation results have a good agreement with the formulation recommended by code.
Bearing Capacity of Steel Tube Tower Connection under Different Thickness of Gusset Plate
Authors: Chen Chen , Zhang Liang , Tang Yake , Zhang Qingfeng , Niu Kai , Pei Haowei , Ju Yanzhong
Published: June 2021

In this paper, a finite element model is established to study the influence of connection plate thickness on the bearing capacity of steel tube tower connections. Through the bearing capacity of connections under different connection plate thickness, the influence of connection plate thickness on the bearing capacity of steel pipe tower connections is analyzed. Finally, the relationship between the thickness of connection plates and the bearing capacity of steel tube tower connections is analyzed by regression analysis. The results show that with the increase of the thickness of gusset plate, the bearing capacity of steel tube tower connections increases linearly. The bearing capacity calculated by regression analysis is in good agreement with the finite element simulation results.
The Analysis of Tunnel Collapse Mechanism and Grouting Reinforcement Measures Under the Unsaturated Seepage Effect
Authors: Zhao Yang , Meng Ren , Wei Huang , Qing Yuan
Published: June 2021

Based on the unsaturated seepage and strength theory, the influence of seepage on tunnel deformation and stability is studied, the mechanism of tunnel collapse under seepage is deeply analyzed, and the grouting reinforcement measures are put forward. The analysis results show that the strength attenuation of unsaturated soil caused by seepage is the main inducement of tunnel collapse. The development of tunnel collapse is controlled by conducting the backpressure of surcharge, improving the softening condition of soil, and grouting reinforcement of soil with weakened strength. Finally, the risk of collapse is effectively solved.
Influence of Aluminum Powder Content on Expansion Rate of Foamed Concrete
Authors: Li Jiaqi , Jin Guangri , Quan Hechun , Jin Xianglin , Jin Man
Published: June 2021

Foamed concrete is a heat preservation and noise reduction material made of cement and aluminum powder as foaming agent. The experiment mainly studies the influence of different water-cement ratio, foaming agent dosage and cement dosage on the expansion rate of foamed concrete test block. The experimental results show that when the water-cement ratio increases from 0.4 to 0.6, the expansion rate decreases gradually. When the content of aluminum powder foaming agent increased from 0.05% to 0.40%, the expansion rate showed a trend of “increasing first and then decreasing”. When other conditions are the same, the expansion rate of cement increases from 500kg/m3 to 800kg/m3, showing a trend of “decreasing first and then increasing”.
Structural Reliability Analysis Using Genetic Algorithm and Gaussian Process Regression
Authors: Xiao Yanjie , Zhang Xun’an , Yue Feng
Published: June 2021

The implicit and computationally time-consuming performance function limits the application of classical reliability analysis methods in complex structures. To facilitate the reliability calculation of civil engineering structures, a reliability analysis method based on genetic algorithm (GA) and Gaussian process regression (GPR) is proposed in this paper. In this method, GPR is adopted to build the surrogate model of performance function, and GA is used for infill-sampling to improve the model accuracy at the limit state surface. Replacing the actual function with this model in Monte Carlo simulation (MCS), the approximate failure probability can be obtained. Four examples are analysed to validate the efficiency and accuracy of the proposed method. The results show that it can deal with the problems of static reliability and seismic reliability, and can be well combined with structural analysis software, which is convenient for engineering designers to use.
Research on quality Inspection method of Topographic Map using oblique Photogrammetry
Authors: Chen Yatong , Cao Jianjun
Published: June 2021

In view of the shortcomings of traditional methods in the quality inspection of large-scale topographic maps in Alpine area and high altitude areas, such as the difficulty of operation and the limited coverage of detection points, this paper puts forward the method of UAV tilt photogrammetry. This paper attempted to replace the traditional quality inspection method in the quality inspection of mathematical accuracy of large-scale topographic maps. By constructing the three-dimensional real scene model of the target area, this paper studied a new method for the quality inspection of large-scale topographic maps, which breaks through the fixed mode that the traditional quality inspection can only be checked by on-the-spot collection, further improve the accuracy and objectivity of the results quality inspection, intensive manpower and material resources, and improve the efficiency and quality of the quality inspection work. Comparing with the traditional check points collected in the field, the UAV tilt photogrammetry method can replace the traditional quality inspection method in the quality inspection of mathematical accuracy of large-scale topographic maps.
Fisheye Image Correction Based on Three-Dimensional Control Field
Authors: Song Ruhao , Zhou Guoqing , Wang Qingyang , Xie Yongfan , Luo Mengyuan
Published: June 2021

The fisheye image has severe distortions, which is not in line with human visual habits and brings inconvenience to its application. This paper classifies them into spherical structural distortion and optical distortion, and proposes a fisheye image correction method based on 3D control field. First, the spherical transformation radius and the optical center of the fisheye image are accurately solved, and the fisheye image is corrected by combining the spherical perspective projection; then, the distortion model of the fisheye camera is introduced into the DLT model to calibrate the optical distortion, and the results are used to recorrect the image. This method has been experimentally proven to be fast and effective.
A Modelling Tool for Rainfall-triggered Landslide Susceptibility Mapping and Hazard Warning based on GIS and Machine Learning
Authors: Zhou Haiwei , Yu Jianjun , Feng Hangjian , Huang Jie
Published: June 2021

The landslide susceptibility mapping and hazard warning are widely adopted tools by the government, stakeholders and the public for landslide disaster preparedness and emergency planning. This study presented a modelling tool based on geographic information system (GIS) and machine learning to aid the two-step modelling procedure. The machine learning methods including artificial neural networks, support vector machines, and logistic regression were integrated into the GIS environment for modelling landslide susceptibility to simplify and automate the routines of model training, verification and prediction. Then, the meta-element model was employed to take the landslide susceptibility, antecedent effective rainfall and 24-hour forecasted rainfall as inputs to determine the landslide hazard level. The architecture to deploy the established meta-element model for real-time landslide hazard warning was also proposed. A study case in Chunan, China was selected to demonstrate the applicability of the modelling tool to aid landslide susceptibility mapping and real-time hazard warning in response to a typhoon event. The developed modelling tool was desired to evolve into cloud computing architecture to facilitate easy-to-reuse and uplift its scalability.