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Underground Space 2024年第5期18卷 114-129页

作者： Haibo Hu Xunjian Hu Xiaonan Gong research center of coastal and Urban Geotechnical Engineering Zhejiang UniversityHangzhou 310058China

The application of steel strut force servo systems in deep excavation engineering is not widespread,and there is a notable scarcity of in-situ measured *** presents a significant research gap in the *** this,our study introduces a valuable dataset and application scenarios,serving as a reference point for future *** main objective of this study is to use machine learning(ML)methods for accurately predicting strut forces in steel supporting structures,a crucial aspect for the safety and stability of deep excavation *** employed five different ML methods:radial basis function neural network(RBFNN),back propagation neural network(BPNN),K-Nearest Neighbor(KNN),support vector machine(SVM),and random forest(RF),utilizing a dataset of 2208 measured *** points included one output parameter(strut forces)and seven input parameters(vertical position of strut,plane position of strut,time,temperature,unit weight,cohesion,and internal frictional angle).The effectiveness of these methods was assessed using root mean square error(RMSE),correlation coefficient(R),and mean absolute error(MAE).Our findings indicate that the BPNN method outperforms others,with RMSE,R,and MAE values of 72.1 kN,0.9931,and 57.4 kN,respectively,on the testing *** study underscores the potential of ML methods in precisely predicting strut forces in deep excavation engineering,contributing to enhanced safety measures and project planning.

关键词： Deep excavation Steel supporting structure Strut forces Machine learning Time Temperature

Dispersal and Fate of Dredged Materials Disposed of in the Changjiang Estuary Determined by Use of An in Situ Rare Earth Element Tracer

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China Ocean Engineering 2011年第3期25卷 495-506页

作者：刘高峰吴华林郭文华朱建荣孙连成 Shanghai Estuarine and coastal Science research center State Key Laboratory of Estuarine and coastal research East China Normal University Tianjin research Institute of Water Transport Engineering

To investigate the dispersal pattern and the fate of dredged materials disposed at a pre-selected disposal site, a field tracer experiment was conducted in the North Passage of the Changjiang Estuary during the 2005 flood season. Three tons of dredged materials were mixed with 2.792 kg of sodium hexachloroiridate （IV） hexahydrate （SHH）, which contained the rare earth element tracer iridum （Ir）. Sampling was conducted at pre-selected sections of the estuary on the second, third and fourth day after the release of dredged materials. All samples were evaluated by use of neutron activation analysis. The majority of the dredged material was dispersed nearly parallel to the navigation channel and deposited between the channel and the south dike. Only a small quantity of dredged materials entered or crossed the navigation channel, and the back silting ratio in the navigation channel was about 5%. The dredged materials also dispersed southeasterly beyond two dike heads.

关键词： dredged material tracer sediment transport Neutron activation analysis deepwater navigation channel of the Changjiang Estuary

Heavy mineral composition and texture of the recently formed fluvial delta sediment of Lake Nasser/Nubia,Egypt and Sudan

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International Journal of Sediment research 2022年第1期37卷 70-82页

作者： Omran E.Frihy Essam A.Deabes Abdelaleem A.budia Ahamed Adawi coastal research Institute National Water Research Center Nuclear Materials Authority

Surficial sediment samples collected from the recently formed fluvial delta in Lake Nasser/Nubia (Egypt and Sudan) in conjunction with data on bottom current and depth soundings are examined to interpret hydraulic-sorting processes and transport/depositional ***～500 km long northeastwardtrending lake,lies within Egypt and Sudan,is created as a result of the construction of the Aswan High Dam in *** original grain-size distribution and heavy mineral compositions of these samples help to characterize the classical depositional features of the recently formed underwater delta-front and prodelta *** from the south,those delta-front deposits,which floor most of the narrow-shallow basin of Lake Nubia,are characterized by thick coarse-grained sandy deposits,rich in heavy minerals (averaged 12.8%).This delta-front is followed to the northeast by thin layers of prodelta mud,poor in heavy mineral contents (averaged 0.6%).These layers cover the entire broad basin of Lake *** northeasterly downslope fining-trend,along with a continuous decrease in heavy mineral composition,along the length of the lake,are attributable to processes of grain sorting,which take place due to contrasting densities and grain *** processes lead to the concentration of heavy mineral placer,mostly in the delta-front *** sorting mechanism,in turn,is controlled by the interplay of unidirectional-directed northeastward current,physiographic characteristics of the lake,including topographic configuration,geometry (cross-section),and floor topography (slope gradient).In terms of mineral exploration,the highest proportion of mineral grades in the delta-front sediments is likely to be considered as a viable source for economic placers that require more planning initiatives for industrial and commercial evaluation.

关键词： Heavy mineral Fluvial delta sediments Delta-front Aswan high dam Hydraulic-sorting processes

Wave-current bottom shear stresses and sediment re-suspension in the mouth bar of the Modaomen Estuary during the dry season

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Acta Oceanologica Sinica 2014年第7期33卷 107-115页

作者： JIA Liangwen REN Jie NIE Dan CHEN Benzhong LV Xiaoying center for coastal Ocean Science and Technology research Sun Yat-sen University

On the basis of the measurement data pertaining to waves, current, and sediment in February 2012 in the mouth bar of the Modaomen Estuary, the Soulsby formulae with an iterative method are applied to calculating bottom shear stresses （BSS） and their effect on a sediment resuspension. Swell induced BSS have been found to be the most important part of the BSS. In this study, the correlation coefficient between a wavecurrent shear stress and SSC is 0.86, and that between current shear stresses and SSC is only 0.40. The peaks of the SSC are consistent with the height and the BSS of the swell. The swell is the main mechanism for the sediment re-suspension, and the tidal current effect on sediment re-suspension is small. The peaks of the SSC are centered on the high tidal level, and the flood tide enhances the wave shear stresses and the SSC near the bottom. The critical shear stress for sediment re-suspension at the observation station is between 0.20 and 0.30 N/m2. Tidal currents are too weak to stir up the bottom sediment into the flow, but a WCI （wave-current interaction） is strong enough to re-suspend the coarse sediment.

关键词： Modaomen Estuary wave-current bottom shear stresses sediment

Bearing capacity and load transfer mechanism of a static drill rooted nodular pile in soft soil areas

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2013年第10期14卷 705-719页

作者： Jia-jin ZHOU Kui-hua WANG Xiao-nan GONG Ri-hong ZHANG research center of coastal and Urban Geotechnical Engineering Zhejiang University ZDOON Building Material Group

The static drill rooted nodular pile is a new type of pile foundation consisting of precast nodular pile and the surrounding cemented *** composite pile has a relatively high bearing capacity and the mud pollution will be largely reduced during the construction process by using this type of *** order to investigate the bearing capacity and load transfer mechanism of this pile,a group of experiments were conducted to provide a comparison between this new pile and the bored *** axial force of a precast nodular pile was also measured by the strain gauges installed on the pile to analyze the distribution of the axial force of the nodular pile and the skin friction supported by the surrounding soil,then 3D models were built by using the ABAQUS finite element program to investigate the load transfer mechanism of this composite pile in *** combining the results of field tests and the finite element method,the outcome showed that the bearing capacity of a static drill rooted nodular pile is higher than the bored pile,and that this composite pile will form a double stress dispersion system which will not only confirm the strength of the pile,but also make the skin friction to be fully *** settlement of this composite pile is mainly controlled by the precast nodular pile;meanwhile,the nodular pile and the surrounding cemented soil can be considered as deformation compatibility during the loading *** nodes on the nodular pile play an important role during the load transfer process,the shear strength of the interface between the cemented soil and the soil of the static drill rooted pile is larger than that of the bored pile.

关键词： Static drill rooted nodular pile Load transfer Bearing capacity ABAQUS Double stress dispersion system Three-dimensional modeling

Effects of the Anthropogenic Activities on the Morphological Evolution of the Modaomen Estuary, Pearl River Delta, China

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China Ocean Engineering 2013年第6期27卷 795-808页

作者：贾良文潘顺琪吴超羽 coastal Ocean research center Sun Yat-sen University School of Engineering Cardiff University

Owing to the intensive human activities, the Modaomen Estuary has been significantly modified since 1950s, which has resulted in considerable changes of hydrodynamics and morphodynamics in the area. In this paper, the effects of the anthropogenic activities on the hydrodynamics and morphological evolution in the estuary at different stages are systematically assessed based on the detailed bathymetric data and field survey. The results show that the human activities have caused the channelization of the enclosed sea area in the Modamen Estuary;fast seaward movement of the mouth bar with high siltation;expansion of the channel volume due to channel deepening. The paper also highlights the main hydrodynamic changes in the estuary, including the rise of the water level;the distinguishing changes of tidal range before and after the 1990s （decrease and increase respectively）; as well as the increase of the divided flow ratio. It is found that reclamation is the main factor promoting the transition of nature of the estuary from runoff dominant to runoff and wave dominant, and sand mining activities are mainly to strengthen the tidal dynamic and to low the water level. The results provide useful guidance for better planning of the future developments in the estuary and further research in the area.

关键词： Modaomen Estuary anthropogenic activities morphological evolution reclamation sand mining

Photoinduced toxicity single and binary mixtures of four polycyclic aromatic hydrocarbons to the marine diatom Skeletonema costatum

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Acta Oceanologica Sinica 2007年第6期26卷 41-50页

作者： MENG Wei WANG Liping ZHENG Binghui River and coastal Environment research center Chinese Research Academy of Environmental Sciences Beijing 100012 China

Diatom Skeletonema costatum Cleve is one of the main predominant phytoplankton species in the Changjiang Estuary in China. In order to provide some basic information for future assessment of the potential risk on phytoplankton communities in this estuary caused by polycyclic aromatic hydrocarbons（ PAHs）, this alga was selected as a representative to investigate the photoinduced toxicity of PAHs, in single and mixture. Four PAHs including three-ring phenanthrene and anthracene, four-ring fluoranthene and pyrene were tested in the laboratory. The single toxicity of each PAH on this microalga was compared with and without the simulated solar UV radiation. The results showed that this microalga was sensitive to PAH＇ s photoinduced toxicity. Ratios of the 72 h median effect concentration obtained for fluorescent and UV light tests were about 8.4 for phenanthrene, 13.0 for anthracene, 6. 5 for fluoranthene, and 5.7 for pyrene, indicating that UV light enhanced the PAH toxicity to this alga significantly. Under the fluorescent radiation （lacking UV ）, the dose-response curves based on chemical concentrations revealed that the order of toxic strength was fluoranthene greater than pyrene greater than anthracene greater than phenanthrene; while under the UV radiation （476 μW/cm^2 for UVA, 6.5 μW/cm^2 for UVB） it became fluoranthene approximately equaling anthracene greater than pyrene greater than phenanthrene, indicating that the UV light also changed its relative toxicity to this alga. The photoinduced toxicity of PAHs to the marine diatom S. costatum might be a synergistic effect of photosensitization reactions （ e. g. , generation of singlestate oxygen） and photomodification （photooxidation and/or photolysis）. The combined effects of six binary mixtures on the marine diatom S. costatum were investigated using the additive-index method. Four binary-mixtures （ phenanthrene plus anthracene ; phenanthrene plus pyrene ; anthracene plus fluoranthene ; anthracene plus pyrene） we

关键词： marine diatom polycyclic aromatic hydrocarbons phototoxicity combined toxicity

Effect of the formation process of transient liquid phase (TLP) on the interface structure of TiAl joints

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Journal of University of Science and Technology Beijing 2005年第5期12卷 431-435页

作者： Huiping Duan Jun Luo Karl-Heinz Bohm Mustafa Kogak School of Materials Science and Technology Beijing University of Aeronautics and Astronautics Beijing 100083 China Institute for Materials research GKSS Research Center Geesthacht 21502 Germany

TiAl has been joined employing the transient liquid phase （TLP） bonding with Ti combined with Cu, Ni or Fe foils. Experimental results showed that though the interface structures of the joints are quite different, all the joined zones are composed of five sublayers, i.e. two diffusion zones, two interfacial zones and an interlayer. It has been convinced that the formation process of the transient liquid phase controls the diffusion behavior of melting point depressant （MPD） Cu, Ni, and Fe atoms, which leads to form different interface structures of the joints.

关键词： TiAl transient liquid phase (TLP) bonding interface

Effect of hot extrusion on microstructure and mechanical properties of quasicrystal-reinforced Mg-Zn-Yalloy

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中国有色金属学会会刊：英文版 2005年第4期15卷 715-721页

作者：郑明毅乔晓光徐世伟甘为民吴昆 S.Kamado Y.Kojima H.G.Brokmeier School of Materials Scienceand Engineering Harbin Institute of Technology Department of Mechanical Engineering Nagaoka University of Technology Institute of Materials Engineering GKSS-Research Center

The microstructure and mechanical properties of as-cast and as-extruded Mg-Zn-Y alloy （Mg-11%Zn-0.9%Y, mass fraction） containing Mg3YZn6 quasicrystal were studied. The eutectic icosahedral quasicrystal phase （I-phase） is broken and almost distributes along the extrusion direction, and fine I-phase with nano-size is precipitated during the extrusion. The α-Mg matrix grains are refined due to recrystallization occuring during the hot extrusion. Some {1012} twins are observed in the extruded ZW1101 alloy. And {0002}〈1010〉 fiber texture is formed in matrix alloys after hot extrusion. The extruded alloy exhibits high strength in combination with large elongation at room temperature. The strengthening mechanism of the as-extruded alloy was discussed.

关键词：镁合金微结构热突出锌

Temporal and spatial changes in nutrients and chlorophyll-a in a shallow lake,Lake Chaohu, China: An 11-year investigation

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Journal of Environmental Sciences 2013年第6期25卷 1117-1123页

作者： Libiao Yang Kun Lei Wei Meng Guo Fu Weijin Yan River and coastal Environment research center Chinese Research Academy of Environmental Sciences Institute of Geographic Sciences and Natural Resources research Chinese Academy of Sciences

Temporal and spatial changes of total nitrogen （TN）, total phosphorus （TP） and chlorophyll-a （Chl-a） in a shallow lake, Lake Chaohu, China, were investigated using monthly monitoring data from 2001 through 2011. The results showed that the annual mean concentration ranges of TN, TP, and Chl-a were 0.08-14.60 mg/L, 0.02-1.08 mg/L, and 0.10-465.90 ~tg/L, respectively. Our data showed that Lake Chaohu was highly eutrophic and that water quality showed no substantial improvement during 2001 through 2011. The mean concentrations of TP, TN and Chl-a in the western lake were significantly higher than in the eastern lake, which indicates a spatial distribution of the three water parameters. The annual mean ratio of TN：TP by weight ranged from 10 to 20, indicating that phosphorus was the limiting nutrient in this lake. A similar seasonality variation for TP and Chl-a was observed. Riverine TP and NH4＋ loading from eight major tributaries were in the range of 1.56× 10^4-5.47 × 10^4 and 0.19 × 104-0.51 × 10^4 tons/yr over 2002-2011, respectively, and exceeded the water environmental capability of the two nutrients in the lake by a factor of 3-6. Thus reduction of nutrient loading in the sub-watershed and tributaries would be essential for the restoration of Lake Chaohu.

关键词： eutrophication Lake Chaohu nitrogen phosphorus