Flow Out of Back-Filling Sand Behind Sea Wall Under Cyclic Water Pressure Variation

Kotani, Yuji; Yoshimura, Chie; Maeno, Shiro; Nago, Hiroshi

doi:10.2208/jscej.2002.712_97

Cited by 5 publications

(2 citation statements)

References 6 publications

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“…Iwasaki et al 2) indicated that the liquefaction of backfilling materials was the cause of sand outflow. Maeno et al 3) and Kotani et al 4) showed that the outflow of backfilling materials was the cause of the destruction of a simple seawall by using a numerical model based on the pore-elastic theory. The formation of the cavity inside the seawall was intimately linked to the cyclical action of water pressure acting on the sand surface.…”

Section: Introductionmentioning

confidence: 99%

Numerical Model for Predicting the Sand Outflow Rate of Backfill Materials From a Coastal Dike

2019

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In the case of coastal dikes and seawalls, since big waves break before reaching these structures, the frequency in which they are broken directly by strong wave force is low. On the other hand, with continuous impact of middle waves, scour arises in these fronts. Before long, incident waves infiltrate into these bodies, backfilling materials flow out, and caves in these bodies become big. Owing to these phenomena, the frequency of destruction of these dikes and seawalls becomes high. Therefore, the development of methods for predicting scour rates in these fronts and sand outflow rates of backfilling materials is useful. Regarding scour rates in these fronts, there are already some accurate methods that specialists can use under various conditions. However, for sand outflow rates of backfilling materials, there are some prediction methods limited to simple types of dikes and seawalls. In this research, the authors develop a numerical model that calculates the flow velocity and pressure in the dike or seawall with arbitrary form using "CADMAS-SURF." The model can predict the time change in the sand outflow rate and the development of the cave. First, for a sand outflow rate simulation, the authors propose empirical equations to modify the pressure calculated by CADMAS-SURF using hydraulic experiment data. Then, they confirm the practical feasibility of the numerical model by applying it to field cases on sand outflow damage in Japan and Thailand.

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Section: Introductionmentioning

confidence: 99%

Numerical Model for Predicting the Sand Outflow Rate of Backfill Materials From a Coastal Dike

2019

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“…Maeno et al [6] and Kotani et al [7] reported that the cyclic action of water pressure on the sand layer precipitated the formation of a cave inside a structure and caused the failure of the structure. The authors proposed a numerical model for simulating cyclic water pressure, based on the poro-elastic theory, which could simulate the cyclic pressure under a simple seawall.…”

Section: Introductionmentioning

confidence: 99%

The Reproduction Ability of a Numerical Model for Simulating the Outflow Rate of Backfilling Materials from a Coastal Structure

Silarom

Yamamoto

2019

JMSE

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In very shallow areas, the frequency by which coastal structures (like dikes and seawalls) are directly broken by large wave forces is low because large waves are broken in deeper areas. The main cause for such destruction is ground scour in front of the structures and outflow of backfilling materials by middle-scale waves; therefore, the scour and the outflow should be considered when designing a coastal structure in a very shallow area. In this paper, a numerical model consisting of CADMAS-SURF, which can calculate fluid motion in porous media, and empirical equations for simulating the outflow phenomena are introduced; thereafter, practical calculations on field cases in Thailand and Japan are demonstrated. Additionally, since the effects of wave periods and water depth to the outflow rate have never been clarified, hydraulic model experiments, empirical calculations using an existing formula, and numerical simulations are performed in order to examine these effects on the outflow rate. The simulated results using the numerical model align well with the experimental results. Moreover, both results show that the outflow rate is proportional to the wave period and inversely proportional to water depth.

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Prototype-Scale Experiment on the Identification of Time-Varying Development and Collapse Processes of a Cavity Under Pavement at Waterfront

YANG,

SASSA,

KUDAI

et al. 2023

Japanese Journal of JSCE

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Flow Out of Back-Filling Sand Behind Sea Wall Under Cyclic Water Pressure Variation

Cited by 5 publications

References 6 publications

Numerical Model for Predicting the Sand Outflow Rate of Backfill Materials From a Coastal Dike

Numerical Model for Predicting the Sand Outflow Rate of Backfill Materials From a Coastal Dike

The Reproduction Ability of a Numerical Model for Simulating the Outflow Rate of Backfilling Materials from a Coastal Structure

Prototype-Scale Experiment on the Identification of Time-Varying Development and Collapse Processes of a Cavity Under Pavement at Waterfront

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