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Land subsidence in coastal reclamation with impact on metro operation under rapid urbanization: A case study of Shenzhen

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Science of the Total Environment 2025年 970卷 179020页

作者： Yang, Xinxin Wu, Huaina Zhou, Suhua Guo, Desai Chen, Renpeng College of Civil Engineering Hunan University Changsha410082 China Hunan Provincial Engineering Research Center of Advanced Technology and Intelligent Equipment for Underground Space Development Changsha410082 China Key Laboratory of Building Safety and Energy Efficiency of the Ministry of Education Changsha410082 China National Center for International Research Collaboration in Building Safety and Environment Hunan University Changsha410082 China

With rapid urbanization in coastal cities, the sharp increase in coastal reclamation due to human activity has caused serious land subsidence problems and threatened the safety of urban traffic in reclamation areas, especially in fast developing cities, such as Shenzhen. However, the spatio-temporal distribution of reclamation evolution and land subsidence to assist in metro operations on a regional scale remain under-explored. To fill-in this research gap, an attempt was made to monitor the coastal reclamation dynamics of Shenzhen from 1979 to *** spatial-temporal changes in the reclamation were discussed based on the Landsat 5, 7 and 8 datasets along with urban growth for a 40-year period. Accordingly, the fill height distribution was employed using available global DEM datasets to perform land fill height effect of metro system in the reclamation area. After understanding the spatial-temporal patterns of land reclamation changes, we focused on monitoring the land subsidence in reclamation area using time-series Sentinel-1 Interferometric SAR (InSAR) datasets by SVD and Stacking techniques. 48 scenes were acquired during ascending and descending passes respectively between 8/3/2015 to 8/8/2023 for the study area. The field measurements of metro deformation in reclamation area acquired from investigation data reflects the risk level of metro operational risk of urban traffic. In-depth analysis of reclamation characteristics revealed a direct relationship between urban expansion, land subsidence and metro deformation. A high correlation coefficient of 0.89 was observed between land subsidence variation and the metro deformation measured along metro line 2 and line 11 in reclamation area. Understanding the impact of land subsidence on metro operation is key to refining sustainable urban development in reclamation areas. © 2025

关键词： Urban planning

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Partially-Premixed Combustion Characteristics and Thermal Performance of Micro Jet Array Burners with Different Nozzle Spacings

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Journal of Thermal Science 2021年第5期30卷 1718-1730页

作者： YANG Haolin WU Yong ZENG Xiaojun WANG Xiaohan ZHAO Daiqing Guangzhou Institute of Energy Conversion Chinese Academy of SciencesGuangzhou510640China Department of Energy and Mechanical Engineering Hunan University of HumanitiesScience and TechnologyLoudi417000China Key Laboratory of Renewable Energy Chinese Academy of SciencesGuangzhou510640China Guangdong Provincial Key Laboratory of New and Renewable Energy Research and Development Guangzhou510640China Guangdong Institute of Special Equipment Inspection and Research Shunde Branch Foshan528300China

In order to develop a burner with uniform temperature field,the combustion characteristics and thermal performance of partially premixed methane/air jet flames were experimentally studied by using micro jet array *** circular tubes of 1.0-mm inner diameter and 1.5-mm outer diameter were used as *** effects of nozzle spacing and equivalence ratio on flame phenomenology,temperature distribution and pollutant emissions were respectively investigated by camera photography,thermocouple measurement and sampling *** show that there are two clean flame patterns:clean merged-flame and clean non-merging *** flame patterns depend on the strength of flame interaction,the equivalence ratio of the mixture and the quantity of air entrainment through the gap between *** burners with small nozzle spacing such as 2 mm and 2.5 mm tend to produce fully merged flame with low equivalence ratio limit and the corresponding temperature fields are very uniform with fluctuations less than 0.3%,but a small increase in equivalence ratio will lead to rapid deterioration of combustion *** burner with a medium spacing of 3 mm can produce partially merged flame in a wide equivalence ratio range with low emissions,and the temperature fluctuation can be less than 0.5%(<7 K)in the optimal *** burner with a large spacing of 4 mm will basically form independent array flames with the largest temperature fluctuation over 1%,while it can achieve clean combustion under high equivalence ratio due to large air *** analysis shows that the micro jet array burner with medium nozzle spacing of 3 mm has the best combustion characteristics and thermal performance.

关键词： micro jet array burner flame interaction methane/air flame temperature fluctuation thermal performance

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Research on the impact of porous media on the flow and acoustic field characteristics for high-speed jet impinging on inclined plate

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Zhendong yu Chongji/Journal of Vibration and Shock 2025年第12期44卷 259-268and307页

作者： Feng, keying Xia, Jing Peng, Yehui Zhao, Kun Shi, Jingyu Hunan Provincial Key Laboratory of Health Maintenance for Mechanical Equipment Hunan University of Science and Technology Xiangtan411201 China Key Laboratory of Aerodynamics Noise Control China Aerodynamics Research and Development Center Mianyang621000 China

The noise from the impact of carrier-based aircraft wake on the deflector plate seriously threatens the health and safety of ground crew, as well asthe equipment on the aircraft carrier. This problem can be simplified to the noise of high-speed jets impacting the deflector plate. A numerical method combining three-dimensional large eddy simulation and FW-H acoustic analogy was employed to investigate the impact of incorporating porous media onto the swash plate' s surface on both the high-speed jet impingement on flow field and the acoustic field . The noise reduction trends was revealed associated with variations in the physical properties of the porous media. Additionally, the mechanisms was analyzed in detail by which porous media influence several types of typical noise, starting from the root cause of flow changes. It is shown that porous media can effectively reduce the discrete monotone and turbulent mixing noise in the jet impingement on flow field. An optimal combination of physical parameters exists, offering the best noise reduction effect. For instance, the porous model with a thickness of 20 mm and PPI of 30 can reduce the discrete monotone near 2 312 Hz up to 19. 79 dB, which results in the total upstream SPL reduction of 6. 92 dB;the suppression of discrete noise by porous media is based on the following principles: porous media affects the stability between the third and forth shock grille, thereby destroying the self-excitation conditions that are closely related to the formation of the feedback loop. The effect of the porous medium on the turbulent mixing noise originates from its destructive impact on the large-scale vortices and its adsorptive effect on the small-scale vortices. This suppresses or transfers the low and medium-frequency broadband noise and effectively reduces the turbulence kinetic energy intensity and pressure fluctuations near the wall surface. © 2025 Chinese Vibration Engineering Society. All rights reserved.

关键词： Large eddy simulation

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Preparation of Novel Highly Stable Fluorinated Microporous Polyketone Networks Through Direct C-H Arylation Polycondensation for Efficient Natural Gas Separation

SSRN

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SSRN 2024年

作者： Li, Gen Yuan, Chunjie Li, Yongqi Ma, Zhongcheng Li, Jiayin College of Chemistry and Materials Science Zhejiang Normal University Jinhua321004 China School of Chemical Engineering Dalian University of Technology Dalian116024 China Hunan Provincial Key Laboratory of Controllable Preparation and Functional Application of Fine Polymers Hunan University of Science and Technology Hunan Xiangtan411201 China State Key Laboratory of Rare Metals Separation and Comprehensive Utilization Institute of Resources Utilization and Rare Earth Development Guangdong Academy of Sciences China

Two novel hyper-cross-linked fluorinated microporous polyketone networks(FMPN-1 and FMPN-2) with permanent porosity and narrow pore size distribution were synthesized via a facile "one-step" polycondensation between the trifluoroacetophenone-based monomers and 1,3,5-triphenylbenzene. The result polymers were investigated by FTIR, solid state NMR, EDX, XRD, TGA, SEM, and TEM et al. The geometry configurations difference of building block resulted in the polyketone networks exhibiting the BET special surface areas from 622 to 706 m2 g-1 and total volume from 0.58 to 0.66 cm3 g-1. What’s more, ideal adsorbed solution theory (IAST) analyses show that the two polymers have good C3H8/CH4, C2H6/CH4 selectivities at 298K/1bar. Together with the excellent thermal and physicochemical stabilities, the microporous fluorinated polyketone networks obtained in this work show promising applications in adsorption/separation for C1−C3 hydrocarbons. © 2024, The Authors. All rights reserved.

关键词： Natural gas

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Preparation of Novel Highly Stable Fluorinated Microporous Polyketone Networks Through Direct C-H Arylation Polycondensation for Efficient Natural Gas Separation

SSRN

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SSRN 2024年

作者： Li, Gen Yuan, Chunjie Li, Yongqi Wang, Chun Ma, Zhongcheng Li, Jiayin College of Chemistry and Materials Science Zhejiang Normal University Jinhua321004 China School of Chemical Engineering Dalian University of Technology Dalian116024 China Hunan Provincial Key Laboratory of Controllable Preparation and Functional Application of Fine Polymers Hunan University of Science and Technology Hunan Xiangtan411201 China State Key Laboratory of Rare Metals Separation and Comprehensive Utilization Institute of Resources Utilization and Rare Earth Development Guangdong Academy of Sciences China

Two novel hyper-cross-linked fluorinated microporous polyketone networks(FMPN-1 and FMPN-2) with permanent porosity and narrow pore size distribution were synthesized via a facile "one-step" polycondensation between the trifluoroacetophenone-based monomers and 1,3,5-triphenylbenzene. The result polymers were investigated by FTIR, solid state NMR, EDX, XRD, TGA, SEM, and TEM et al. The geometry configurations difference of building blocks resulted in the polyketone networks exhibiting the BET special surface areas from 622 to 706 m2 g-1 and total volume from 0.58 to 0.66 cm3 g-1. What’s more, ideal adsorbed solution theory (IAST) analysis showed that the two polymers possessed good C3H8/CH4, C2H6/CH4 selectivities at 298K/1bar. Together with the excellent thermal and physicochemical stabilities, the microporous fluorinated polyketone networks obtained in this work showed promising applications in adsorption/separation for C1−C3 hydrocarbons. © 2024, The Authors. All rights reserved.

关键词： Natural gas

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Facile Preparation of Nanoporous Triphenylamine-Based Polyaminals with High Porosity for Efficient Co 2 Uptake and Fast Waste Treatment

SSRN

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SSRN 2024年

作者： Li, Gen Yuan, Chunjie Li, Yongqi Hu, Yaling Gu, Haonan Ge, Yi Ma, Zhiyuan Zhou, Zhihua College of Chemistry and Materials Science Zhejiang Normal University Jinhua321004 China Hunan Provincial Key Laboratory of Controllable Preparation and Functional Application of Fine Polymers Hunan University of Science and Technology Hunan Xiangtan411201 China State Key Laboratory of Rare Metals Separation and Comprehensive Utilization Institute of Resources Utilization and Rare Earth Development Guangdong Academy of Sciences China Science and Technology on Advanced Ceramic Fibers and Composites Laboratory National University of Defense Technology Changsha410073 China

Two novel robust triphenylamine-based nanoporous polyaminal networks (NTP-m1 and NTP-p1) with high porosity were prepared through a facile "one-step" polycondensation utilizing six active amino groups 4,4’,4’’-tris(2,4-diaminotriazinyl)triphenylamine(TDATPA) as triangle-liked core monomer and isophthalaldehyde or terephthalaldehyde as chain monomer without adding any catalysts in the medium of dimethyl sulfoxide. The BET special surface areas were up to 1138 m2 g-1 and 1518 m2 g-1, and total volume were 1.6 and 1.18 cm3 g-1 for NTP-m1 and NTP-p1, respectively. The main pore size of NTPs centered at microporous range. The synergistic role of numerous CO2-philic triazine rings, the narrow pore size distribution and excellent high specific surface areas in the polyaminal networks brought about high adsorption capacity of carbon dioxide up to 18.1wt%. Moreover, the microporous polyaminal networks exhibiting effective separating carbon dioxide over nitrogen and methane. The relationships between the geometry configuration of the building blocks and porosity parameters as well as their eﬀects on the adsorption/separation abilities of CO2/N2, CO2/CH4 were investigated in detail with respect to adsorption capacities, and polarities of CO2, N2, and CH4 gases. Furthermore, the role of the porous structure of the polyaminal networks resulted in the fast Rhodamine B dye uptake ability, and the high RhB dye sorption capacity up to 813mg/g. Together with the excellent physicothermal stabilities, the microporous polyaminal networks obtained in this work showed promising applications for carbon capture sequestration and wastewater treatment. © 2024, The Authors. All rights reserved.

关键词： Carbon dioxide

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Numerical investigation of bolt anchorage with tension force and shear force 5

Numerical investigation of bolt anchorage with tension force...

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2020 5th International Conference on Minerals Source, Geotechnology and Civil Engineering, MSGCE 2020

作者： Chen, Yu Li, Yongde Hunan Provincial Key Laboratory of Hydropower Development Key Technology Hunan province Changsha410014 China China Construction Fifth Engineering Division Corp. Ltd Hunan province Changsha410000 China

The bolt anchorage with tension force and shear force are studied numerically by FLAC3D modelling. A tri-linear material model was utilized for the bolt steels in order to simulate the strain hardening behaviour of the materials. The numerical modelling show that different types of bolts have similar load capacities, while their deformation capacities are different. The numerical results match the laboratory test results. The different deformation capacities of rock bolts are attributed to their different bonding conditions and stretching lengths. The axial load in the rebar bolt reduces exponentially from the loading point close to the joint to the bolt end. The axial load in the D-Bolt has its maximum at the joint and reduces slowly as the distance from the joint increases. © Published under licence by IOP Publishing Ltd.

关键词： Bolts

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2D inversion of frequency-domain electromagnetic data generated by line current source 2

2D inversion of frequency-domain electromagnetic data genera...

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2020 2nd International Conference on Computer Modeling, Simulation and Algorithm, CMSA 2020

作者： Deng, Xiaokang Tong, Xiaozhong Hunan Provincial Key Laboratory of Hydropower Development Key Technology Mid-south Design and Research Institute Hunan China School of Civil Engineering Hunan University of Technology Hunan China School of Geosciences and Info-Physics Central South University Hunan China

The inversion of electromagnetic data is an inherently non-unique and unstable problem due to the data noises and incomplete data coverage, which means different geo-electrical models could fit the observed data at the same level. A stable solution of an ill-posed inverse problem can be obtained by the regularization methods in which some desired structure are imposed to stabilize the inverse problem. We have developed an algorithm to invert frequency-domain electromagnetic data generated by a line current source for a 2D model of the earth. To stabilize the inversion, we adopt a smoothness-constraint approach for the model parameters and adjust the regularization parameter objectively using an adaptive regularization parameter technique. For calculating the sensitivities using any of the accurate methods will be very time-consuming, we applied the adjoint-equation approximate method. By means of the numerical examples using synthetic data, we have demonstrated that the inversion method can be effectively to reconstruct the subsurface resistivity structure. © 2020 Institute of Physics Publishing. All rights reserved.

关键词： Inverse problems

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Research on Structural Features and Their Impact on the development of Shale Oil from the Chang 7 Formation in QingCheng Area of the Ordos Basin 10th

Research on Structural Features and Their Impact on the Deve...

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10th International Field Exploration and development Conference, IFEDC 2020

作者： Zhang, Jie Liao, Jian-ping Huang, Li-gang Zhao, Yu-hua Zhao, De-yong Zhu, Jun Exploration & Development Research Institute of PetroChina Changqing Oilfield Company Xian China Hunan Provincial Key Laboratory of Shale Gas Resource Utilization Hunan University of Science and Technology Xiangtan411201 China National Engineering Laboratory for Low-Permeability Oil/Gas Exploration and Development Xian China

ISBN: (纸本)9789811607622

The shale oil resources of the Chang 7 Member of the Yanchang Formation in the Qingcheng area of the Ordos Basin in China has been exploited through the use of horizontal wells. The area is located in the main part of the Ordos Basin, which is a monoclinic west-dipping structure with a dip angle of less than 1°. Previous studies suggested that the structure of this area is relatively simple with an absence of faults. Because structural features and faults in particular have a great impact on horizontal well drilling, 3D seismic real field data were acquired at the end of 2018 to study the structural characteristics of the base of Chang 7 member to support horizontal well drilling, using fault identification techniques such as structural velocity mapping, coherence and curvature. For the first time we identify two phases of faults. The first phase is a normal fault within the Yanchang Formation, with a trend of NW-SE (northwest, southeast), with a fault distance of 5–20 m and a short extension, formed at the end of the deposition of the Chang 4 + 5 members. The second phase is a left-handed strike-slip fault with a NEE-SWW (north-east-east-south-west-west) direction, a fault distance of 5–15 m, and a long extension. It was formed in the early Cretaceous. The overall structure in this area is gentle but the structure near the fault shows wide variation. The significance of this observation is on the engineering approach to horizontal well drilling. Although the fault has little effect on shale oil accumulation, close to the fault at distances greater than 10 m the potential for water production and the loss of drilling fluids affects the effective drilling rate for horizontal wells. The results of this analysis means that the deployment of shale oil horizontal wells in this area has been optimized, and the horizontal well trajectory guided while drilling, improving exploitation in the Ordos Basin. © 2021, The Author(s), under exclusive license to Springer Nature Singa

关键词： Horizontal wells

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Downward Soil Arching Below Excavation Base: Theory and Application

SSRN

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SSRN 2024年

作者： Wu, Kai Meng, Fan-Yan Chen, Ren-Peng Wang, Han-Lin Hunan Provincial Engineering Research Center for Advanced Technology Intelligent Equipment for Underground Space Development Hunan University Changsha410082 China Research Center for Advanced Underground Space Technologies of Hunan University Changsha410082 China Key Laboratory of Building Safety and Energy Efficiency of the Ministry of Education Hunan University Changsha410082 China College of Civil Engineering Hunan University Changsha410082 China

Downward soil arching would generate and develop below excavation base due to soil mass excavation. The excavation-induced soil arching, which is related to soil resilience characteristics and excavation dimension, dominates the ground stress transfer and deformation propagation below excavation base. This paper proposes a theoretical model for downward soil arching to predict the soil stress and deformation below excavation base. According to the soil’s three-phase resilience characteristic under vertical unloading, the model classifies the soil mass below excavation base into the loosened zone and the arching zone. Subsequently, a prediction method for ground stress and basal heave is established based on the major and minor principal stress trajectories below excavation base. The important prediction factors are considered including the overconsolidated lateral earth pressure coefficient, stress-dependent elastic unloading modulus, groundwater table depth, and surcharge on excavation base. Two centrifuge tests and two case histories verify the applicability of the proposed model and method. The loosened zone is featured with significant weakness in soil stiffness and noticeable resilient deformation. In comparison, the mobilization of the arching effect and effective constraint in resilient deformation is found in the arching zone. © 2024, The Authors. All rights reserved.

关键词： Excavation

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