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LARGE-SCALE OPEN-CHANNEL EXPERIMENTS ON THE COLLAPSE OF ABUTMENT BACKFILL OWING TO FLOODS AND PROPOSED COUNTERMEASURE
Get PDFIn Japan, great damage to abutment backfills caused by large-scale floods occurs every year. It is necessary to examine the fundamental collapse mechanism on as close to full scale as possible, in order to achieve a sufficient effect of the similarity laws in geotechnical engineering, river engineering, and bridge engineering. In this study, geotechnical evaluations were carried out, such as observation of pore water pressure behavior in an embankment, settlement of an embankment crest, and applicability of a reinforced soil wall as a countermeasure construction, under conditions affected by flowing water. The results show that the collapse behavior of an embankment surface differs depending on the soil properties of the embankment material. The erosion of the river bed progressed even in the footing lower surface of the abutment foundation and in the upstream side of the abutment, where the flow velocity was locally large and changes in the flow direction were confirmed. In addition, when a gabion-reinforced earth wall with water permeability was used for the wall surface construction as a countermeasure, washout of the embankment in the abutment to the extent that a pavement surface above would collapse did not occur, thereby confirming the gabion’s usefulness as a countermeasure.journal articl
本川の水位変動を考慮した支川の小規模河床波 の発達と水位上昇に関する研究 -小規模河床波の発達に対する 下流端水位の影響
Get PDFIn recent years, tributary rivers that join major rivers have been frequently overflowed. The main river
has been improved and strengthened so that it can withstand higher water levels than before. The high water
level in the main river acts as a backwater and raises the water level in the tributary rivers, causing flooding
at the confluence and in the tributary rivers. Therefore, it can be said that the potential risk of the tributary
rivers is increasing. Therefore, it is an urgent issue from the perspective of disaster prevention to calculate
the amount of water level rise in the tributaries caused by water level fluctuations in the main river.
On the other hand, it is known that the water level at the time of runoff is affected by the development of
small-scale riverbed waves. In the present study, we investigate the effect of water level changes in the
downstream end of the main river on the development of small-scale riverbed waves.
In this study, the downstream end water level is considered to be the water level at the confluence, and the
objective is to understand the development of small-scale riverbed waves according to the downstream end
water level and the characteristics of the longitudinal profile of the water level that may be affected by the
waves.journal articl
MELTING CHARACTERISTICS OF CNTDISPERSED LATENT HEAT STORAGE MATERIAL IN RECTANGULAR TANK WITH VERTICAL HEAT TRANSFER SURFACE
Get PDFProceedings of the 2021 International Workshop on Modern Science and Technology; September 29, 2021conference pape
A DUAL-BAND MICROSTRIP ANTENNA DESIGN AND ANALYSIS METHOD BASED ON MULTI BRANCH
Get PDFProceedings of the 2021 International Workshop on Modern Science and Technology; September 29, 2021conference pape
AUTOMATIC SENTIMENT SCORE GENERATION METHOD FOR SIGHTSPOTS REVIEW SYSTEM
Get PDFProceedings of the 2021 International Workshop on Modern Science and Technology; September 29, 2021conference pape
IMPROVEMENT OF QUANTITATIVE LEARNER'S MOTIVATION METHOD BY OPTIMIZING THE COMBINATION OF THE ELEMENTS
Get PDFProceedings of the 2021 International Workshop on Modern Science and Technology; September 29, 2021conference pape
OVERVIEW OF RESEARCH PROGRESS OF GENERATIVE ADVERSARIAL NETWORKS IN VIDEO PREDICTION
Get PDFProceedings of the 2021 International Workshop on Modern Science and Technology; September 29, 2021conference pape
Antarctic Peninsula warm winters influenced by Tasman Sea temperatures
Get PDFThe Antarctic Peninsula of West Antarctica was one of the most rapidly warming regions on
the Earth during the second half of the 20th century. Changes in the atmospheric circulation
associated with remote tropical climate variabilities have been considered as leading drivers
of the change in surface conditions in the region. However, the impacts of climate variabilities
over the mid-latitudes of the Southern Hemisphere on this Antarctic warming have yet to be
quantified. Here, through observation analysis and model experiments, we reveal that
increases in winter sea surface temperature (SST) in the Tasman Sea modify Southern Ocean
storm tracks. This, in turn, induces warming over the Antarctic Peninsula via planetary waves
triggered in the Tasman Sea. We show that atmospheric response to SST warming over the
Tasman Sea, even in the absence of anomalous tropical SST forcing, deepens the Amundsen
Sea Low, leading to warm advection over the Antarctic Peninsula.journal articl
八代海における淡水流入の影響を考慮した海水中CO2動態の数値モデリング
Get PDF大気中のCO2削減に関して沿岸域の吸収機能が注目されている．本研究では，沿岸域のCO2動態に関する基礎的な知見を得ることを目的に，八代海における現地観測の結果を基に淡水流入の影響を考慮した海水中CO2(pCO2)動態の数値モデルを開発した．開発したモデルは，異なる成層条件でのpCO2や塩分・水温の時空間分布を良く再現できた．モデルによる計算結果より，河口周辺のCO2吸収量は河川の出水に伴って時空間的に大きく変動することが確認された．さらに，出水が沿岸域のCO2吸収量に及ぼす影響として以下が確認された．i) 出水直後は表層の淡水層によりCO2放出が促進される．ii) 混合が進み塩淡成層が弱まると，表層に植物プランクトンの極大層が現れ，光合成によりCO2吸収が促進される．journal articl
アマモの呼吸と光合成を考慮したコムケ湖における溶存無機炭素水平分布の再現
Get PDF北海道北東部に位置するコムケ湖でアマモの呼吸と光合成を考慮したDIC水平分布について検討した．従来のSAV model（Submerged Aquatic vegetation model）は，湖等の大規模計算を行う際に，アマモの本数が多いため，計算時間が膨大になるという欠点を有していた．そこでまず，実現象にSAV modelを適用するために，複数の水草（Submerged Aquatic vegetation: SAV）を1本で代表させるSuper SAV modelの再現性の検討を行った．流速分布と拡散係数の分布を比較することによって再現性を検討したところ，十分な再現性を確保したうえで，計算時間の大幅な短縮に成功した．さらに，実現象へSuper SAV modelを開発・適用し，呼吸と光合成の効果を考慮することで，DICを高精度に再現できる可能性を示すことができた．journal articl