- ポスターセッション１：[ P01-01 ] から [ P01-29 ] まで
- ポスターセッション２：[ P02-01 ] から [ P02-24 ] まで
- ⇒2020年度・応用力学シンポジウムのサイトへ

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- 第１部門：物理数学力学問題 ー物理現象のモデル化から逆問題までー
- 第２部門：計算力学
- 第３部門：材料・複雑現象の力学
- 第４部門：流体力学
- 第５部門：応用数理問題―計算機科学から社会科学まで
- 企画 (リスク定量化とその応用)：分野横断型・企画セッション１
- 企画 (浸透・浸食)：分野横断型・企画セッション２

第１部門：[ P01-01 ]

トポロジー感度を欠陥検出指標に用いた二次元動弾性時間反転解析とリニアアレイ探傷法への応用

2-D elastodynamic time-reversal analysis using topological sensitivity and its application to ultrasonic linear array testing

田代 匡彦, 斎藤 隆泰(群馬大・理工学府),

木本 和志(岡山大・環境生命科学研究科)

木本 和志(岡山大・環境生命科学研究科)

This study conducts 2-D elastodynamic time-reversal analysis using topological sensitivity. The time-reversal method is one of the eﬀective inverse scattering technique to detect a defect in elastic solids. The topological sensitivity is utilized to determine the convergence area of time-reversed waves from a linear array transducer. The convolution quadrature time-domain boundary element method (CQBEM) for 2-D elastodynamics is used to obtain scattered and time-reversed wave fields. Some defect detection results obtained by using this approach are demonstrated to investigate the performance of the present method.

[講演概要📄はこちら]

[講演概要📄はこちら]

第１部門：[ P01-02 ]

応力均一化を実現する樹枝形状の理論探索

Exploring the Tree Branch Tapering under the Uniform Stress Axiom

市川 祐実(山梨大院・生命環境), 佐藤 太裕(北大院・工),

島 弘幸(山梨大院・総合)

島 弘幸(山梨大院・総合)

In the growth process of trees, a mechanical support function is indispensable for securing a stable structure that can withstand the own weight and wind pressure. A remarkable feature of trees is the stress uniform distribution; i.e., they grow their trunks and branches autonomously so that the stresses generated on the surface are uniform. But this established idea poses a following question: what shape of tree branches can achieve such a uniform stress distribution? In the present work, we have calculated the equilibrium state of a main branch, which was affected only by its own weight, within a small deformation range, and examined the effects of the branch tapering and cross-sectional shape variation on the deflection curve and stress distribution of the branch. We have found that the bending stress distribution can reach an almost uniform stress distribution under certain geometric conditions with respect to the outer shape.

[講演概要📄はこちら]

[講演概要📄はこちら]

第１部門：[ P01-03 ]

蜘蛛が張る円網の振動解析に向けた実験法の提案

Developing an experimental apparatus for analyzing the vibration of

a spider orb web

a spider orb web

野垣 佳佑 (山梨大・生命環境), 津川 暁 (奈良先端大・バイオ),

島 弘幸 (山梨大院・総合)

島 弘幸 (山梨大院・総合)

The physicochemical properties of spider silk, which is a material for spider webs, have been actively studied thus far. On the other hand, the vibration characteristics of the entire spider web have not yet been elucidated, though it should be closely related to spider ecology. In this study, we aimed to establish an experimental method for investigating the vibration mechanism of a circular-shaped spider web. The effectiveness of the method was demonstrated by filming the vibration of rubber string-based spider-web model and performing Fourier analysis on the measured data.

[講演概要📄はこちら]

[講演概要📄はこちら]

第１部門：[ P01-04 ]

二足歩行の力学的エネルギー消費に関する近似モデルの提案

An approximate theory for mechanical energy consumption of bipedal locomotion

村山 蓮 (山梨大・生命環境), 島 弘幸 (山梨大院・総合)

There are few types of terrestrial animals that move by bipedal walking. Among them, the ostrich is famous as an animal that can move at high speed for a long time. A better understanding of the structure of the ostrich's leg and the locomotion mechanism, therefore, will open an avenue for the design of a high-speed, energy-efficient bipedal walking mechanism. This motivated us to develop a theoretical model that represents human bipedal walking and to calculate its energy efficiency, as a first step towards the long-term goal of the ostrich problem. The model led us to the conclusion that the amount of mechanical energy required for walking changes in a non-trivial manner with the step length and walking speed.

[講演概要📄はこちら]

[講演概要📄はこちら]

第１部門：[ P01-05 ]

竹の種別による形状の違いと共通性に関する考察

Shape Difference and Commonality in Different Types of Bamboos

柳井 駿斗 (北大院・工), 亀山 侑平 (北大院・工), 島 弘幸 (山梨大院・総合),

井上 昭夫 (近畿大・農), 佐藤 太裕 (北大院・工)

井上 昭夫 (近畿大・農), 佐藤 太裕 (北大院・工)

Bamboo is widely used as a functional and natural material in Japan and several other Asian countries. Our resent researches have shown the novel mechanical characteristics of moso bamboo (Phyllostachys pubescens ). In this study we investigate the shape difference and common structural characteristics of five bamboo species from the analysis of measurement data.

[講演概要📄はこちら]

[講演概要📄はこちら]

第１部門：[ P01-06 ]

超音波計測に基づく花崗岩中の表面波伝播特性に関する研究

A Study on the Propagation Characteristics of Surface Waves in
a Granite Based on Ultrasonic Measurement

木本 和志, 岡野 蒼 (岡山大・環境生命科学), 斎藤 隆泰 (群馬大・理工学府),

佐藤 忠信 (神戸学院大・現代社会学部),

松井 裕哉 (日本原子力研究開発機構・幌延深地層研究センター)

佐藤 忠信 (神戸学院大・現代社会学部),

松井 裕哉 (日本原子力研究開発機構・幌延深地層研究センター)

This study investigates the propagation characteristics of high frequency surface wave in a granite block by ultrasonic measurement. In the experiment, a surface wave field excited by a line-focus transducer is scanned finely over a rectangular aperture with a laser Doppler vibrometer. From the measured waveforms, the spatial distribution of Fourier phase is reconstructed, and the structure of the wave front configuration is investigated. Due to the heterogeneity of the granite, we find the fluctuation of the wave front measured by the distribution of spatial gradient of phase. The intensity of the fluctuation is quantified as a local wavenumber vector. As the result it is found that the granite sample can be characterized by a stochastic wave number whose probability density is frequency dependent, asymmetric and non-Gaussian with a finite support.

[講演概要📄はこちら]

[講演概要📄はこちら]

第２部門：[ P01-07 ]

ステンレス製パネルタンクの流体と構造を連成しての時刻歴応答解析

Time History Response Analysis of Fluid and Structure for Stainless Steel Panel Tank

竹本純平 (中央大院・理工), 小野泰介 (中央大院・理工),

平野廣和 (中央大・総合政策), 佐藤尚次 (中央大・理工)

平野廣和 (中央大・総合政策), 佐藤尚次 (中央大・理工)

In recent years, many stainless steel (SUS) panel tanks have been installed as for water supply facilities in order to facilitate maintenance and shorten construction time. Although these tanks are designed and constructed according to the latest design standards, there have been so many cases of damage in SUS tanks due to severe earthquakes such as the Tohoku-Pacific Ocean Earthquake and the Kumamoto Earthquake. In this paper, the time history response analysis of a 3000 × 3000 × 3000mm SUS tank is carried out to show local stress behavior which can cause damages. As a result, it is necessary to study more on the relationship between SUS body stiffness in order to avoid damages under earthquake which can modify future design condition.

[講演概要📄はこちら]

[講演概要📄はこちら]

第２部門：[ P01-08 ]

等曲げモーメントを受けるCFRP接着補修鋼板の力学特性

Mechanical behavior of CFRP bonded repair of thickness-reduced steel plate under pure bending

水谷 壮志 (関西大院・理工), 石川 敏之 (関西大・環境都市工)

In this study, the shear lag theory using the conventional differential equation was extended to the CFRP bonded repair of the thickness-reduced plate under pure bending. The surface stress of the members obtained from this result almost agreed with the finite element analysis. Furthermore, it was found that the surface stress at the thickness-reduced section repaired by bonding CFRP is almost the same as that of the composite theory.

[講演概要📄はこちら]

[講演概要📄はこちら]

第２部門：[ P01-09 ]

模擬劣化RC梁の移動輪荷重下変形挙動の画像解析

Image analysis on the deformation behaviors of RC beams with simulated deteriorations under a moving wheel load

永井 崇雅 (北海道大・工), 松本 高志 (北海道大・工), 角間 恒 (北海道開発局),

西 弘明 (寒地土木研究所)

西 弘明 (寒地土木研究所)

Using an image analysis method, the deformation behaviors of RC beams with artificial damage were investigated under a moving wheel load condition. The two beams were loaded simultaneously with a moving wheel under dry and wet surface condition, respectively. This study focused on the maximum principal strain and maximum shear strain of the beam with wet surface condition. Analytical results clearly showed that the deformation behaviors in the upper part of the specimen were affected by wheel load positions.

[講演概要📄はこちら]

[講演概要📄はこちら]

第２部門：[ P01-10 ]

SPHシミュレーションによる斜面崩壊の定量的評価に関する研究

A Study on Quantitative Evaluation of Slope Failure using SPH Simulation

野中 沙樹 (神戸大・工), 大石 哲 (神戸大・工), 阿波田 康裕 (JAXA)

The reproduction and quantitative evaluation of past landslide disaster cases will lead to the evaluation of the risk of slope failure and the prediction of the damage after the collapse. The purpose of this study is to perform high-speed calculations by parallelizing 3D large-scale SPH simulations that model real ground. In the calculation for the actual ground, the calculation was performed on about 1.45 million particles, and it was shown that parallel calculation with high scalability was performed. Therefore, it is suitable as a framework for large-scale calculation.

[講演概要📄はこちら]

[講演概要📄はこちら]

第２部門：[ P01-11 ]

四辺形・六面体のノード再配置法による有限変形計算法

A numerical scheme for finite strain theory by adaptive nodal relocation (ANR) method for quadrilateral / hexahedron

今村 純也（*imi* 計算工学研究室）

The objective of this study is to establish a numerical scheme for solid represented by Helmholtz decomposition (*H-d*). Based on the *H-d*, arbitrary vector field **V** can be represented using scalar potential φ and vector potential **ψ** as follows, i.e. **V**= ∇φ + curl**ψ** (div**ψ** =0). In a previous report, I proposed an improved Helmholtz decomposition (*iH-d*) for displacement vector **u** ; i.e. **u** =∇φ + ∇φ^{I} + curlψ ( ∇^{2}φ^{I}=0, div**ψ**=0), and ∇**ψ**·**1**= ∇^{2}**Ψ**, where **Ψ** is potential but has a similar dimension to **u**. By numerical model based on the finite deformation theory, the nodes must follow the Lagrangian tracking. This report proposes an adaptive nodal relocation (ANR) method, where the distortional term in the function of hexahedron play an important role for the nodal relocation. The objective to represent in *iH-d* is to avoid so-called numerical Locking.

[講演概要📄はこちら]

[講演概要📄はこちら]

第２部門：[ P01-12 ]

固液混合MPMによる海底地滑りに起因する津波シミュレーション

Solid-liquid coupled material point method for tsunami caused by submarine landslide

潘紹元 (東北大), 山口 裕矢 (東北大), 森口 周二 (東北大), 寺田 賢二郎 (東北大)

The applicability of MPM (Material Point Method) combined with mixture theory is investigated from the perspective of predicting tsunami hazards induced by submarine landslide. By use of two overlapped layers for soil and water particles, soil-water mixture and incompressible fluid models are used to respectively represent the submarine landslide and the resulting tsunami event in a consistent manner. Numerical example is presented to simulate the collapse of an undersea soil slope on the seabed and examine the performance in reproducing the fluidized soil movement and resulting elevated waves.

[講演概要📄はこちら]

[講演概要📄はこちら]

第２部門：[ P01-13 ]

津波エネルギー低減効果に与える防潮堤勾配の影響

Influence of tidewalls slope on tsunami energy reduction effect

橋本 憲二 (八工大), 小笠原 亮介 (八工大), 高瀬 慎介 (八工大),

金子 賢治 (八工大), 加藤 雅也 (釧路高専)

金子 賢治 (八工大), 加藤 雅也 (釧路高専)

In the wake of the 2011 the Great East Japan Earthquake, research on toughness dike structures has been done. In previous studies at, it has been clarified that steep tidewalls have a great reduction effect on tsunami energy transmission to the hinterland. Additionally, Study on scouring measures of Landside toe of slope and dike structures using geosynthetics materials to realize steep banking, obtained the knowledge of toughness resistance to long time overflow by designing using submerged unit weight. However, there are cases of collapse despite satisfying stability, and the flow of water in the foundation ground is considered. In this research, numerical analysis of the tsunami energy reduction effect is performed, including the cases that have not been implemented in the experiment.

[講演概要📄はこちら]

[講演概要📄はこちら]

第２部門：[ P01-14 ]

洪水解析に基づくため池周辺の家屋被害の推定

Estimation of house damage around reservoir body based on flood analysis

和田 光真 (香川大院・工), 吉田 秀典 (香川大・創造工)

Reservoirs are expected to be protected against mega earthquake damages. The immediate collapse of reservoirs due to a large earthquake, the houses around the reservoir are estimated damage due to the same fluid power as the tsunami. However, it is difficult to apply real damage to various types of reservoirs. Therefore, numerical analysis can be considered by an effective method for predicting damage. In this study, the flood analysis is conducted with reference to the damage example of a house collapsed by strong fluid force due to few data of reservoirs damage. Analyzes the hydrodynamic forces of the flood and suggests ways to use the results to determine house collapse.

[講演概要📄はこちら]

[講演概要📄はこちら]

第２部門：[ P01-15 ]

高速演算性と高精度性を両立した浸水域予測のための地形適合セルの機械的な生成法

Mechanical generation method of terrain-adaptive cells for ﬂood-inundation analysis

佐々木 靖幸 (新潟大・工), 諸岡 良優 (中央大学

(現 国立研究開発法人土木研究所)), 安田 浩保 (新潟大)

(現 国立研究開発法人土木研究所)), 安田 浩保 (新潟大)

Flood-inundation analysis using terrain-adaptive cells can ﬂexibly describes complex terrain shapes in urban areas. However, it is difficult to generate the terrain-adaptive cells by man hands. In this study, we developed a method to mechanically generate the cells from the road network data. We also calculated using mechanically generated terrain-adapted cells are performed. As a result, 1) the mechanically generate cells can be accurately estimated the expansion speed of inundated area, and 2) contribute to the high-speed calculation.

[講演概要📄はこちら]

[講演概要📄はこちら]

第２部門：[ P01-16 ]

ASI-Gauss法による都市全域の木造家屋倒壊解析手法の開発

Development of seismic response analysis method for the whole city by ASI-Gauss code

石井 秀尭 (九州大・工), 浅井 光輝 (九州大・工), 磯部 大吾郎 (筑波大),

大谷 英之 (理化学研究所)

大谷 英之 (理化学研究所)

During the 2011 off the Pacific coast of Tohoku Earthquake and the 2016 Kumamoto Earthquake have caused devastating damages, collapsing lots of wooden houses. Restoration and reconstruction after these huge disasters delayed to remove a large amount of debris including collapsed house members. It is estimated that the same-scale earthquakes and accordingly tsunamis in the Nankai Trough region will be happen. Therefore, it is very important not only estimating the tsunami run-up in advance but also risk management such as evaluating the total amount and spread of debris, securing rescue routes, and temporary rubble storage sites. In this study, the wooden house collapse simulation is conducted with the ASI-Gauss code, which is one of the large deformation FEM code with the Timoshenko beam element. Then, the ASI-Gauss code is enhanced in order to simulation large scale city models. In the future, it is required to carry out a city-scale seismic response analysis with the past earthquake log for a validation of our developed code.

[講演概要📄はこちら]

[講演概要📄はこちら]

第２部門：[ P01-17 ]

Probabilistic seismic risk assessment of buildings in Thailand based on proper orthogonal decomposition

固有直交分解によるタイにおける構造物の地震時確率論的リスク評価

Junxian LI, Hidekazu USAMI (Dept. of Civil Eng., Tohoku University),

Shuji MORIGUCHI, Kenjiro TERADA (IRIDeS., Tohoku University)

Shuji MORIGUCHI, Kenjiro TERADA (IRIDeS., Tohoku University)

This study presents a new framework for probabilistic risk assessment of buildings under seismic conditions. A part of Chiang Mai city (Thailand) is selected as a target area, and a building damage evaluation method developed in HAZUS is employed in the numerical simulations. We prepared simulated results with a variety of situations by changing locations of earthquake sources and their magnitudes. Based on the obtained results, the seismic risk of buildings in Chiang Mai is analyzed. The proposed framework can provide an efficient approach to the probabilistic seismic risk analysis, and it has a high potential for disaster risk assessment.

[講演概要📄はこちら]

[講演概要📄はこちら]

第２部門：[ P01-18 ]

非硬化塑性ひずみ領域を導入した拡張下負荷面モデルの完全陰的

応力計算法の開発

応力計算法の開発

Fully implicit stress-update algorithm for extended subloading surface model incorporating nonhardening plastic strain region

井口 拓哉 (東北大・工), 佐藤 大貴 (東北大・工), 羅 家驊 (東北大・工),

山川 優樹 (東北大・工)

山川 優樹 (東北大・工)

In this study, a novel implicit stress-update algorithm of the subloading surface model, a class of unconventional plasticity modes, incorporating the nonhardening plastic strain region is developed to improve the predictive capability for cyclic loading property. Ohno (1982; J. Appl. Mech., ASME) proposed an improved plasticity model equipped with nonhardening plastic strain region in order to reproduce the stagnation of isotropic harden-ing resulting in transient stabilization of hysteresis loop during cyclic loading with a fixed strain amplitude. In the plastic strain space, when the plastic strain moves inside the region, isotropic hardening does not proceed, while only kinematic hardening proceeds, and hence the region does not expand. When the plastic strain moves outside of the nonhardening region, isotropic hardening proceeds being accompanied by expansion of the region. As a specific prototype model, von Mises plasticity model is reformulated based on the hyperelastic constitutive equations within the framework of infinitesimal deformation theory. A numerical algorithm for stress calcula-tion using return mapping is developed, in which we devise a novel scheme consisting of scheme consisting of hardening/nonhardening judgment, substep technique, and nested iteration to update variables associated with nonhardening plastic strain region.

[講演概要📄はこちら]

[講演概要📄はこちら]

第２部門：[ P01-19 ]

飽和粘性土地盤の支持力解析における引張り領域の取扱いに

関する一考察

関する一考察

Study on inﬂuence of tensile stress zone in saturated clay on ultimate bearing capacity

山栗 祐樹 (金沢大・自然研), 小林 俊一 (金沢大・理工), 西藤 潤 (京都大・工),

松本 樹典 (金沢大・理工)

松本 樹典 (金沢大・理工)

For metal material models, shear strength does not depend on mean stress. Aφ = 0 material such as saturated clay is also the same. For φ = 0 material, even if a mean stress is on tensile stress zone, it will not aﬀect to failure behavior in metal material model. But, previous studies that examined the applicability of the metal material model to the failure behavior of the ground material, haven’t been found. In this paper, numerical experiments were conducted, to investigate the inﬂuences of tensile stress zone of soil on ultimate bearing capacity, using a rigid-plastic finite element method based on the lower bound theorem.

[講演概要📄はこちら]

[講演概要📄はこちら]

第２部門：[ P01-20 ]

多数の静止固体間を流れるニュートンおよびビンガム流体から

構成される２流体の数値計算

構成される２流体の数値計算

Computations of Two Fluis Consisting of Newtonian and Bingham Fluids Moving between Multiple Static Solid Objects

大野 絢平 (京大・工), 鳥生 大祐 (京大・ACCMS), 牛島 省 (京大・ACCMS)

The two-ﬂuid system consisting of Bingham and Newtonian ﬂuids is sometimes seen in the area with multiple solid objects, such as mortar ﬂows between aggregates and grouting-materials ﬂows in rock fractures. In this study, the phase-averaged governing equations are utilized for the two-ﬂuid system of Newtonian and Bingham ﬂuids. The governing equations are discretized with the finite volume method with the collocated grid system. The dam-break ﬂows of the Bingham ﬂuids surrounded by the Newtonian ﬂuids were calculated with the present method. From the numerical experiments, the eﬀects of the non-dimensional yield stress of Bingham ﬂuids are investigated together with the number of the fixed square objects in the computational area.

[講演概要📄はこちら]

[講演概要📄はこちら]

第２部門：[ P01-21 ]

有限体積法による高粘性ニュートン流体の容器充填の数値計算

Computations of Container Filling with Highly Viscous Newtonian Fluids Based on Finite Volume Method

九鬼 愛夢 (京大・工), 鳥生 大祐 (京大・ACCMS), 牛島 省 (京大・ACCMS)

Computations of container filling with highly viscous Newtonian ﬂuids are conducted with the finite volume method using a collocated grid system. In this study, phase-averaged governing equations are solved for the multi-phase field, which consists of two incompressible fluids with different densities and viscosities. As a result, it is confirmed that our method enables us to reasonably predict ﬂow patterns of highly viscous liquids, such as steady filling, splashing and buckling, which arise in the specific relationships between Reynolds number and the ratio *H/d*, where *H* is the height of the container and *d* is the inlet width, as reported in the preceding studies.

[講演概要📄はこちら]

[講演概要📄はこちら]

第５部門：[ P01-22 ]

都市地震シミュレーションの数値解析統合とその利活用に関する

基礎的研究

基礎的研究

Fundamental Study on Numerical Analysis Integration for Regional Earthquake Simulation - Integration Process and Application -

飯山 かほり (東工大), 河瀬 理貴 (神戸大), 堀 宗朗 (JAMSTEC),

マッデゲデラ ラリス (東京大), 井料隆雅 (神戸大)

マッデゲデラ ラリス (東京大), 井料隆雅 (神戸大)

This study seeks to compromise the temporal/spatial resolution (the granularity) difference in integrating different simulations. There are two approaches for the compromise, taking either average or maximum of results of the finer granularity simulation. We make numerical experiments using Integrated Earthquake Simulator for an actual urban area by integrating structural response analysis and traffic flow analysis, and demonstrate the effect of different approaches on damage evaluation. We also analyze the impacts of the structural damages on the traffic flows.

[講演概要📄はこちら]

[講演概要📄はこちら]

第５部門：[ P01-23 ]

時間域境界積分方程式法を用いたバーチャル空間を移動する受音点

でのリアルタイム可聴化について

でのリアルタイム可聴化について

A study on real-time auralization on a moving point in the virtual space using time domain BIEM

吉川 仁 (京大・情報), 鈴木 賢人 (京大・情報)

A numerical computation of a sound that a character moving in the virtual space hears is considered. We solve the initial-boundary value problem of wave equation using time domain BIEM and store the computed boundary values in advance. We compute the sound of the moving point with the integral representation formula in real time using Unity3D.

[講演概要📄はこちら]

[講演概要📄はこちら]

第５部門：[ P01-24 ]

割合を考慮したファジィ分割表と類似係数

Fuzzy Contingency Table including Total Ratio and Similarity Indices

上江洲 弘明 (金沢工業大・数理工教育研究センター)

The contingency table analysis provides the interrelation between two variables and can help find interactions between them. Previously, we extended the contingency table by applying fuzzy theory and defined a fuzzy 2×2 contingency table. However, this definition cannot be extended to fuzzy m×n contingency tables. In this paper, we propose the “new” definition of fuzzy m×n contingency table and apply to similarity index calculation.

[講演概要📄はこちら]

[講演概要📄はこちら]

第５部門：[ P01-25 ]

X線CTと機械学習を用いた農業水利施設におけるコンクリート損傷の可視化

Visualization of Concrete’s Damage in an Agricultural Canal Structure by X-ray CT and Machine Learning

島本 由麻 (北里大・獣医), 鈴木 哲也 (新潟大・農)

Cracks in concrete are visualized by using X-ray CT. Conventionally, the cracks from CT images have been extracted by binarization processing with threshold setting. The conventional method has a problem that the evaluation accuracy varies greatly depending on the set value of the threshold. In this study, concrete’s cracks are extracted by X-ray CT image processing with the decision tree method. The specimens were taken from an agricultural canal structure with frost damages. Five explanatory variables were set: Brightness, the pixel value after the DoG (Difference of Gaussian) filter, the maximum pixel value at 2 × 2 pixel, the minimum pixel value at 2 × 2 pixel, and the difference between the maximum and minimum pixel values. The decision tree method can achieve the same or better evaluation accuracy than the conventional method. Therefore, the decision tree method seems to be effective for obtaining stable accuracy under various measurement conditions.

[講演概要📄はこちら]

[講演概要📄はこちら]

第５部門：[ P01-26 ]

鋼矢板護岸における腐食実態の画像診断

Image Analysis of Corroded Condition in Service Steel Sheet Piles

萩原 大生 (新潟大学大学院・自), 島本 由麻 (北里大学・獣),

鈴木 哲也 (新潟大学・農)

鈴木 哲也 (新潟大学・農)

Textural characteristics of visible images of corroded steel sheet pile are important information of the corroded condition. In this study, spatial distribution characteristics in visible images of the corroded steel sheet pile are evaluated by texture analysis using gray level co-occurrence matrix. As a result, by utilizing saturation channel, the textural homogeneity of a non-corroded steel sheet pile is higher value than a corroded one. Considering the spatial anisotropy, there is a difference of the homogeneity in the long length and the short one. The textural characteristics of non-corrosion and corrosion could be quantitatively evaluated by the textural homogeneity and the spatial anisotropy.

[講演概要📄はこちら]

[講演概要📄はこちら]

企画 (リスク定量化とその応用)：[ P01-27 ]

地震発生後の車両通行性に着目した既存橋梁システムのフラジリティ解析

Fragility Analysis of Existing Bridge Systems Focusing on Traffic Passability after Earthquake Event

サキャ 摩耶 (横国大・都市イノベ), 西尾 真由子 (筑波大・シス情)

After a major earthquake event, there is a case that the vehicles cannot become passing on the bridge due to the damages in bearings and expansion joints caused by large dynamic displacement. In this study, the fragility analysis was conducted focusing on the vehicle passability after the earthquake event on two bridges with different structural characteristics considering the effects of deterioration damages on the existing bridges. As the results, it was shown that the deterioration damage affected the large vehicles passability after the earthquake, and may decrease the vehicle passability as the bridge structure system.

[講演概要📄はこちら]

[講演概要📄はこちら]

企画 (リスク定量化とその応用)：[ P01-28 ]

Real-Time Tsunami Simulations with Surrogate Modeling

代理モデルを用いたリアルタイム津波シミュレーション

Joseph GALBREATH, Reika NOMURA (Department of Civil Engineering, Tohoku University), Shuji MORIGUCHI,

Shunichi KOSHIMURA, Kenjiro TERADA (IRIDeS., Tohoku University)

Shunichi KOSHIMURA, Kenjiro TERADA (IRIDeS., Tohoku University)

There have been many numerical models proposed for tsunami propagation simulations. They are all very numerically intensive, requiring days to complete the calculations. For probabilistic risk analysis, which requires many simulations, these methods are infeasible. Therefore, in this paper, we propose a framework of surrogate modeling, which introduces the potential of real-time risk assessment. To create the surrogate model, we calculated the prominent modes of the given data, after which we used RBF interpolation for mapping the input data points to their corresponding coefficients. The surrogate model this constructed is expected to be accurate, given the simulation cases used are sufficiently dense for the complexity of the results.

[講演概要📄はこちら]

[講演概要📄はこちら]

企画 (リスク定量化とその応用)：[ P01-29 ]

実河川の河床形態と川幅水深比の相関性について

Relationship between bed forms and aspect ratio of river channel

田所 祐輝 (新潟大・工), 安田 浩保 (新潟大・工)

The channel width-to-depth ratio can estimate occurrence sandbars in gravel bed rivers well. How-ever, applicability of existence of sandbars by the width-to-depth ratio is unknown. In this study, we investigate the width-to-depth ratio to estimate existence of sandbars in actual 11 rivers. On this estimation, ﬂow depth was calculated using the uniform ﬂow formula for practical purpose. As a result, we showed that the width-to-depth ratio can estimate existence of sandbars using uniform ﬂow formula.

[講演概要📄はこちら]

[講演概要📄はこちら]

第３部門：[ P02-01 ]

火成岩の破断パターンにみられる揺らぎの普遍性

Universal geometric fluctuation in fracture patterns of igneous rocks

秋葉 祐里 (山梨大院・工), 高島 愛果 (山梨大院・生命環境),

島 弘幸 (山梨大院・総合)

島 弘幸 (山梨大院・総合)

Columnar joint is a regular pattern of cracking in igneous rock that forms an array of slender columns with polygonal cross section. In this study, we considered the geometry and topology of the polygonal crack tessellation observed at the outcrop surface of columnar joints. Aerial photo shooting of the columnar joint was conducted at four different sites in Japan to obtain a sufficient amount of image data for numerical replication of the polygonal crack patterns. Using the primary data, we examined the similarity and difference in the statistical properties of the polygon geometry between the four sites. The results imply a universal fluctuation in the skewness of polygons, which quantifies the geometric discrepancy in the polygon shape from the regular counterpart. It was also discovered that the geometric fluctuation is characterized by Gumbel distribution, irrespective to lithographic and geographic conditions under which the columnar joint formed.

[講演概要📄はこちら]

[講演概要📄はこちら]

第３部門：[ P02-02 ]

粉体系・液体系の重力不安定性現象における共通的性質

Close relation between gravitational instability of liquid systems and granular materials

小林 和也 (都立大・理), 栗田 玲 (都立大・理)

Gravitational instability (Rayleigh-Taylor instability), which is a typical example of hydrodynamic instabilities, occurs due to density difference. When a heavy fluid lies over a light fluid in a constant gravitational field, fluctuations at the interface gradually increase and then macroscopic flows occur. The gravitational instability can be found not only in liquid-liquid interface but also in the gravitational settling of granular materials (granular-gas interface). However, the gravitational instability of liquid systems and granular systems have been discussed individually in most cases. We find a interesting relationship between the granular system and the physical gel. We also find that those behaviors are determined by the depth of the fluidization.

[講演概要📄はこちら]

[講演概要📄はこちら]

第３部門：[ P02-03 ]

異なる積層構造を有するCFRPの曲げ変形挙動の画像解析

Image analysis of bending deformation behaviors of CFRP with different laminate structures

遠藤 祐希 (北海道大・工), 鄧 朋儒 (北海道大・工), 松本 高志 (北海道大・工)

CFRP has high strength and high stiffness in addition to its low density, however CFRP exhibits a brittle behavior at the time of fracture. In this study, cross-ply laminate, helicoidal laminate within limited angle range and cross-ply laminate core with helicoidal laminate skin were tested under three-point bending, and image analysis were performed for deformation behaviors. From the image analysis, it was confirmed that the deformation behaviors did not conform to those of the beam theory. It was observed that the epoxy resin between prepregs affected the deformations and that the out-of-plane deformations of the helicoidal laminate possibly were present.

[講演概要📄はこちら]

[講演概要📄はこちら]

第３部門：[ P02-04 ]

損傷モデルによるコンクリートの非均質性に関するモンテカルロ

シミュレーション

シミュレーション

Monte Carlo Simulations for Meso-scale Heterogeneity of Concrete by a Damage Model

佐々木 浩武 (茨城大院・理工), 加藤 匠 (茨城大院・理工),

車谷 麻緒 (茨城大院・理工)

車谷 麻緒 (茨城大院・理工)

Monte Calro simulations are carried out to investigate the inﬂuence of the heterogeneity with respect to the grain size of coarse aggregates in concrete on the fracture properties. The concrete is regarded as three-phase composite materials composed of mortar, aggregates, and the interface. A damage model that allows a kind of mesh-free finite element analysis is used for modeling cohesive crack growth.

[講演概要📄はこちら]

[講演概要📄はこちら]

第３部門：[ P02-05 ]

局所弾塑性応答に基づく鋼材の疲労亀裂伝播寿命評価

－ 応力集中場に存在する表面亀裂の進展特性 －

－ 応力集中場に存在する表面亀裂の進展特性 －

Fatigue crack propagation life predicted by local elastoplasticity response - Surface crack propagation from a notch with stress concentration -

堤 成一郎 (大阪大・接合研), 長濱啓和 (大阪大・接合研),

清川裕樹 (大阪大・接合研), FINCATO Riccardo (大阪大・接合研)

清川裕樹 (大阪大・接合研), FINCATO Riccardo (大阪大・接合研)

This paper investigates the surface crack propagation life based on the local elasto-plasticity response at crack tip. Fatigue crack propagation including its life and the profiles are assessed as a continuous behavior of fatigue crack initiation in this study. Firstly fatigue crack initiation life is assessed by 3-dimentional cyclic elasto-plasticity analyses and Δε-Nc criterion. Then fatigue crack growth rate is calculated as da/dN = Δa/Nc, where Δa is a fatigue crack growth length parameter. It is verified that fatigue crack propagation life in the depth and width directions is accurately assessed by comparing with the corresponding experimental results.

[講演概要📄はこちら]

[講演概要📄はこちら]

第３部門：[ P02-06 ]

礫の衝突位置の違いによるフランジ継手付き鋼管はりの耐荷性能

Load Carrying Capacity of Steel Pipe Beams with Flange Joints by Difference between Impact Positions of Boulder

國領 ひろし (日鉄建材), 堀口 俊行 (防衛大・工), 別府 万寿博 (防衛大・工),

園田 佳巨 (九州大・工), 石川 信隆 (防衛大)

園田 佳巨 (九州大・工), 石川 信隆 (防衛大)

This paper presents an analytical approach on the load carrying capacity of steel pipe beams with flange joints against boulder impact by changing the impact position of boulder. First, this method was validated by comparing with the static and dynamic test results. Second, the load carrying capacities of steel pipe beams (fixed and cantilever beams) with flange joints were investigated by changing the impact positions of boulder using the static and dynamic elastic-plastic FEM analyses.

[講演概要📄はこちら]

[講演概要📄はこちら]

第３部門：[ P02-07 ]

Rainfall Infiltration and Slope Stability: a case study in Marumori, Miyagi, Japan

降雨浸透と斜面安定性：宮城県丸森町の事例研究

Nilo Lemuel J. DOLOJAN (Department of Civil Engineering, Tohoku University), Shuji MORIGUCHI, Kenjiro TERADA,

(IRIDeS, Tohoku University)

(IRIDeS, Tohoku University)

Shallow landslides and slope failures in Marumori, Miyagi during the October 2019 typhoon Hagibigs are acknowledged to be induced by heavy rainfall. Using rainfall intensity and soil characteristics, infiltration capacity and depth of infiltration can be estimated. In this study, the Green-Ampt equation, adapted for inclined surfaces, is used to estimate infiltration depths along critical slopes. Assigning the computed infiltration depths as the slip surface depth, the factor of safety is then calculated using the infinite slope stability model. Translating this model into raster processes, a visualization map of a time-varying factor of safety for Marumori can be generated.

[講演概要📄はこちら]

[講演概要📄はこちら]

第３部門：[ P02-08 ]

密度変化を考慮した不飽和土/水/空気連成解析

Unsaturated soil / water / air coupled analysis considering density

山下 大輝 (福島高専), 金澤 伸一 (福島高専)

In recent years，many cases of collapse and damage of soil structures have been reported due to the increase of sudden heavy rains (guerrilla heavy rains，typhoons，etc.) due to climate change，and they are suffering from sediment disasters every year．To date，the analysis of the causes of collapse of soil structures and their mechanisms have not been fully elucidated．However，in geotechnical engineering，long-term prediction of soil structures using numerical analysis has been conducted，and research on optimal design focusing on performance has been advanced．In this laboratory，we have clarified the behavior of the embankment and river embankment in consideration of rainfall and rising water level using the air-dissolved unsaturated soil / water / air coupled finite analysis code (DACSAR-MP)．However，since the incremental balancing equation is defined as σ'_(ji，j)=0，it is impossible to take into account the state change due to external factors，that is，the effect of the unsaturated density change．In this study，we propose an incremental balancing equation applied to unsaturated soil and reflect it in the analysis code to compare the density change of unsaturated soil due to external factors.

[講演概要📄はこちら]

[講演概要📄はこちら]

第３部門：[ P02-09 ]

施工条件を考慮した盛土の築造・供用過程における応力解析

Stress analysis on construction and in-service to embankment considering construction conditions

鈴木 聡恵 (福島高専・産業技術システム工学専攻),

金澤 伸一 (福島高専・都市システム工学科)

金澤 伸一 (福島高専・都市システム工学科)

In recent years, many examples of soil structure collapse due to heavy rainfall have occurred. Because of this, it is urgent to establish a method to evaluate and examine long-term embankment structure quality. Japan's conventional design method insufficiently evaluates embankments. Although this method is shifting to a performance-based design to cope with recent abnormal weather, an effective design method has not yet been established. Therefore, this research performs an initial stress analysis of embankment, accounting for differences in construction conditions. Notable in this study, is the comparative analysis of results, considering the initial water content ratio, one layer of discharge thickness, rolling compaction, and other given structural conditions that differed from conventional design standards. Based on the dynamics of unsaturated soil, the rainfall intensity was analyzed in order to confirm the variation of the initial stress due to rainfall. Lastly, and most critically, the dynamic change in embankment performance by the aging was analytically expressed, and the optimal structural conditions of embankment, grouped by rainfall history, was examined.

[講演概要📄はこちら]

[講演概要📄はこちら]

第３部門：[ P02-10 ]

土粒子破砕を伴う地盤材料の圧縮性の評価について

Evaluation of Compressibility of Geomaterials with Soil Particle Breakage

瀬戸内 秀規 (琉球大・農)

The large compressibility with particle breakage of Ryukyu limestone sands is predicted by the power rule of logarithm void gradient. It is revealed that the different compressibility from initial void ratio is evaluated in the material constants ξ of the power rule, and the different compressibility from particle strength is evaluated in the hardening/softening coefficient __K___{0} of the power rule.

[講演概要📄はこちら]

[講演概要📄はこちら]

第４部門：[ P02-11 ]

物理モデルと統計モデルを融合した不等流のエネルギー損失の推定法の開発

Development of estimation method for energy loss in non uniform ﬂow by combining physical model and statistical model

茂木 大知 (新潟大・工), 安田 浩保(新潟大・工), 大竹 雄(新潟大・工)

In oder to accurately determine energy loss in non uniform ﬂow using mathematical model of open channel ﬂow, velocities and depth of water must be simultaneously measured with high resolution. However, energy loss in non uniform ﬂow (IeN(x)) which has spatial distribution, has been cal-culated generally using the Manning formula as energy Loss in uniform ﬂows. In this study, to estimate IeN(x), we investigate a new solution method combining physical model analysis and in-verse analysis. We performed a simple 1-dimensional numerical analysis which estimate IeN(x)’s energy loss coefficient to confirm the applicability.

[講演概要📄はこちら]

[講演概要📄はこちら]

第４部門：[ P02-12 ]

レベルセット法とVOF法の特徴比較

A Comparative Study of Level Set Method and Volume of Fluid Method

石川 秀平 (静岡大・院工), 横嶋 哲 (静岡大・工), 久末 信幸 (関西電力),

早瀬川 拓馬 (静岡大・院工)

早瀬川 拓馬 (静岡大・院工)

Both level set methods and volume of ﬂuid (VOF) methods are popular for computation of immiscible-ﬂuid ﬂows. Here a comparative study of the ACLS (accurate conservative level set) method, a level set variant, and the CICSAM (compressive interface capturing scheme for arbitrary meshes) method, a VOF variant, in terms of accuracy and eﬃciency has been carried out. Several benchmark tests revealed that the ACLS method combined with a high-order scheme shows a remarkable ability for interface capturing. While the CICSAM is available only at low-CFL-number conditions, its accuracy comparable to the ACLS method and easiness of implementation are also desirable. Application to the steady state air bubble test, which requires coupling with a Navier-Stokes equation solver, presented that a sophisticated method for calculation of interface normal and curvature is essential for VOF methods when surface tension force plays an important role.

[講演概要📄はこちら]

[講演概要📄はこちら]

第４部門：[ P02-13 ]

対流境界層の乱流熱輸送機構における都市キャノピの影響

Effects of Urban Canopy on Turbulence Heat-Transfer Process in Convective Boundary Layer

服部 康男 (電中研), 石原 修二 (DCC), 須藤 仁 (電中研), 中尾 圭佑 (電中研),

長谷部 憂麿 (DCC), 平口 博丸 (電中研)

長谷部 憂麿 (DCC), 平口 博丸 (電中研)

Large-eddy simulations (LES's) for a thermally convective flow above buildings and streets (an urban canopy) in the atmospheric boundary layer are performed. Special attention is paid to the effects of the buildings on turbulence heat transfer processes in the vertical direction of the atmospheric boundary layer. LES's clearly show that the buildings yield the dissimilarity between thermal and flow fields, i.e., the vertical profiles of turbulence statistics and also coherence structures in the thermal fields significantly differ from those in the flow fields.

[講演概要📄はこちら]

[講演概要📄はこちら]

第４部門：[ P02-14 ]

流砂関数を用いた不等流におけるエネルギー勾配の推定

Estimation of energy gradient in the non-uniform ﬂow using the Mayer-Peter-Muller formula

黛 由季 (新潟大・工), 安田 浩保 (新潟大・工)

Energy gradient of open channel ﬂow has been generally estimated with the Manning’s formula for uniform ﬂow. Therefore, almost natural river form non-uniform ﬂow, it is unclear whether energy gradient of uniform ﬂow can be applied non-uniform ﬂow. We calculated the energy gradient of non-uniform ﬂow using the Mayer–Peter–Muller formula. We showed that the difference between energy gradient in non-uniform ﬂow and in uniform ﬂow with roughness coefficient as constant is more than 50%.

[講演概要📄はこちら]

[講演概要📄はこちら]

第４部門：[ P02-15 ]

砂州の発達過程における澪筋の川幅水深比とその安定性

Stability and the width-to-depth ratio in stream during the development of a sand bars

村井 剛徳 (新潟大・工), 安田 浩保(新潟大・工)

In a straight gravel river, those channel width is stable and not infinite. In other hand sides, alternate bars are often spontaneously formed in gravel rivers, and a linear stream is maintained stably in response to their development. The above-mentioned stable channel width and the linear straight stream of the latter suggest some relationship. In this study, we investigated stability of channel width at the width-to-depth ratio which was obtained during the development processes of alternate bars. We showed that the ratio is a condition for suppressing the occurrence of alternate bars, and therefore, stable channel shape was kept due to the straightness of stream line is kept.

[講演概要📄はこちら]

[講演概要📄はこちら]

第４部門：[ P02-16 ]

2019年出水時の千曲川における流路変動解析

Numerical simulation of sand bar and channel evolution process of the Chikuma River caused by the 2019 flood

岩崎 理樹 (北大・工), 奥田 醇(北大・工), 清水 康行(北大・工)

In this paper, we perform a numerical simulation of sand bar and channel evolution processes of the Chikuma River caused by a huge flood event observed in 2019. The numerical results show that the huge flood causes a downstream migration of sand bars, which had been fixed for last decades, resulting in a significant change of channel pattern and bank erosion. The result is reasonably consistent with the observed river evolution.

[講演概要📄はこちら]

[講演概要📄はこちら]

企画 (浸透・浸食)：[ P02-17 ]

固液混合MPMを用いた地盤構造物のマルチステージ浸透破壊解析

Multi-stage seepage failure simulation of ground structures using solid-liquid coupled material point method

山口 裕矢 (東北大), 飛驒野 荘真 (東北大), 高瀬 慎介 (八戸工大),

森口 周二 (東北大), 金子 賢治 (八戸工大), 寺田 賢二郎 (東北大)

森口 周二 (東北大), 金子 賢治 (八戸工大), 寺田 賢二郎 (東北大)

A multi-stage collapse process of ground structures caused by seepage flow is simulated with a coupled material point method based on the theory of porous media. The continuum of the mixture is discretized with a set of Lagrangian material points that possess the information about both the geometry and material of solid and liquid. Both explicit and implicit schemes are combined to improve the robustness and efficiency in computations. A model experiment for seepage failure is simulated to demonstrate the capability of the proposed method in dealing with the transition from the quasi-static to the dynamic state of the unsaturated soil.

[講演概要📄はこちら]

[講演概要📄はこちら]

企画 (浸透・浸食)：[ P02-18 ]

非球形粒子間隙を通過するNon-Boussinesq密度流の数値解析

Computations of Non-Boussinesq Density Currents between Multiple Non-Spherical Particles

田中 寛樹 (京大・工), 鳥生 大祐 (京大・ACCMS), 牛島 省 (京大・ACCMS)

This paper deals with the computational method for the density currents between multiple non-spherical particles with a phase-averaged model, in which no empirical formulations, like a permeability *k* and a drag coefficient C_{d}, are needed. In addition, density currents caused by wide range of density ratio can be predicted reasonably since the Boussinesq approximation is not used in our method. The numerical experiments were conducted to understand the inﬂuence of the cell-porosity resolution *R*, which is defined as the spatial resolution of the ﬂuid cells against the volume that is not occupied by the solid particles.

[講演概要📄はこちら]

[講演概要📄はこちら]

企画 (浸透・浸食)：[ P02-19 ]

吸水性粒子の間隙における自由液面流れの数値解析手法

Computational Method for Free-Surface Flows between Multiple Absorbent Particles

永野 浩大 (京大・工), 鳥生 大祐 (京大・ACCMS), 牛島 省 (京大・ACCMS)

A computational method was proposed for the free-surface ﬂows between multiple absorbent particles on the basis of the finite volume method with the collocated grid system. In the proposed method, the swelling of the particle due to the water absorption is considered with the velocity boundary conditions on the particle surfaces. The proposed method was applied to the dam-break ﬂows in the porous media, which consists of multiple absorbent particles, to confirm its applicability. As a result, it is demonstrated that the free-surface ﬂow patterns are largely aﬀected by the swelling particles and that the ﬂows between particles are possibly blocked by the swelling particles in case that the water absorption speed is suﬃciently high.

[講演概要📄はこちら]

[講演概要📄はこちら]

企画 (浸透・浸食)：[ P02-20 ]

バネ・ダッシュポット支持された捕捉粒子で分離される粒子群と

自由表面流れの計算

自由表面流れの計算

Computation of Moving Particles and Free-Surface Flows around Trapping Particles Fixed with Spring and Dashpot Model

廣岡 信行 (京大・工), 牛島 省 (京大・ACCMS)

This paper describes the applicability of the two-dimensional computational method to predict the sieving filtration, which is used to trap ”moving particles” from the particle-laden liquid ﬂows. A ﬂexible porous structure for the sieving filtration is modeled with the ”trapping particles”, each of which connects to its initial position with a spring and dash-pot structure. The dam-break liquid ﬂows including moving particles were calculated in the area where the trapping particles were placed. As a result, it was shown that the moving particles are retained by the trapping particles and that the sieving filtration is reasonably simulated.

[講演概要📄はこちら]

[講演概要📄はこちら]

企画 (浸透・浸食)：[ P02-21 ]

交互砂州の発生・発達過程における底面位の伝播速度式の適用性

Applicability of Celerity Equation for Bottom in the Development Process of Alternate Bar

石原 道秀 (新潟大・工), 安田 浩保 (新潟大・工)

Until now, poor understanding of the propagation characteristics of alternate bars, which are wave phenomena, is that the formulation of the theoretical equation for its celerity has not been estab-lished. In this study, we firstly derived the two-dimensional theoretical equation for celerity of riverbed waves. Secondly, we verified applicability of its equation for alternate bars using temporal and spacial high-resolution measured values. As a result, we clarified that its equation have high accuracy for estimation of alternate bars celerity if froude number is lower than 1.0.

[講演概要📄はこちら]

[講演概要📄はこちら]

企画 (浸透・浸食)：[ P02-22 ]

侵食破堤の危険箇所の複眼的推定法の構築

Development of prediction method of bank erosion on both micro and macro scale

石塚 芳 (新潟大・工), 梅木 康太朗 (新潟大・工), 石原 道秀 (新潟大・工),

五十嵐 拓実 (株式会社キタック), 安田 浩保 (新潟大・工)

五十嵐 拓実 (株式会社キタック), 安田 浩保 (新潟大・工)

Bank erosion is typical failure in gravel bed rivers. We have developed an prediction method of bank erosion point due to uneven distribution of ﬂood ﬂow using tractive force. However, the method is based on physical model that is not neglect any uncertainly. In this study, we try to combine new prediction method focusing on river bed shape with the previous method using ﬂume experiment and numerical simulation of actual river. We showed that both prediction methods can estimate bank erosion point well.

[講演概要📄はこちら]

[講演概要📄はこちら]

企画 (浸透・浸食)：[ P02-23 ]

不飽和土/水連成問題における排水パイプ工の表現

Expression of drain pipe on unsaturated soil/water coupling problem

河井 克之 (近畿大学・理工), 赤木 悟 (京都大学大学院・工),

中島 晃司 (近畿大学・理工), 安冨 懸一 (日鉄建材株式会社),

大高 範寛 (日鉄建材株式会社)

中島 晃司 (近畿大学・理工), 安冨 懸一 (日鉄建材株式会社),

大高 範寛 (日鉄建材株式会社)

Elevation of the phreatic surface causes instability of an earth structure. Therefore, drainage system is important on constructing an earth structure. Drain pipe is the drain system applicable even for an existing earth structure. In this study, the drain pipe was expressed in the initial and boundary problems on unsaturated soil. Here, the results of electrical prospecting were compared with seepage analysis on the embankment installed drain pipe. Consequently, qualitative agreement between them was found.

[講演概要📄はこちら]

[講演概要📄はこちら]

企画 (浸透・浸食)：[ P02-24 ]

外水位変動を考慮した河川堤防の破堤要因に対する解析的検討

Analytical study on factors of river levee breach considering External water level fluctuation

一条つばさ (福島高専・建設環境工学科),

金澤伸一 (福島高専・都市システム工学科)

金澤伸一 (福島高専・都市システム工学科)

In recent years, localized torrential rains have frequently occurred in various parts of Japan, and frequent river levee collapses have occurred. However, the mechanism of river embankment collapse has been discussed, but not fully understood.Therefore, in this study, we performed embankment analysis considering the difference in layer thickness using the unsaturated soil / water / air coupled element finite method analysis program (DACSAR-MP), and focused on embankment reinforcement and rainfall. At that time, it was analytically confirmed that the failure mode of the embankment was different due to the difference in the rising speed of the external water level.

[講演概要📄はこちら]

[講演概要📄はこちら]