A bank‐stability analysis is incorporated into an analytical procedure for modeling the hydraulic geometry of an alluvial gravel‐bed channel. The new analysis includes a procedure that calculates the mean bed and bank shear stress as well as assessing the bank stability. The bank‐stability criterion accounts for the increased stability of the channel banks due to consolidation of the bank sediment, cementing by fines, and binding of the sediment by root masses. The two key parameters in the bank‐stability analysis are the median grain diameter of the bank sediment D50bank, and the modified friction angle of the bank sediment φ′. A sensitivity analysis of the two parameters indicate that the bank stability can exert a large influence on the channel geometry. This is supported by testing the theory on published field data. The bank sediment size was assumed to equal the bed sediment size, and the variation of the friction angle φ′ was investigated. The estimated φ′ values are seen to increase systematically...

Closure of "Effect of Bank Stability on Geometry of Gravel Rivers"

Test data to compare the resulting behavior with that observed under cyclic loading triaxial test conditions are presented. It is concluded that the liquefaction characteristics observed in the two types of tests are qualitatively similar. However, under cyclic simple shear conditions, which provide a close simulation of the stresses induced under field conditions, the cyclic shear stresses required to cause liquefaction were only about 35% of those determined by more approximate triaxial test procedures. It is suggested, however, that limitations of the simple shear test procedure induce liquefaction at stress levels perhaps 40% to 50% lower than those corresponding to actual field conditions, and that a correction factor of this order of magnitude should be applied to laboratory simple shear test data intended for use in the analyses of field problems. The test program also showed that frequency effects, within the range from 1/6 cps to 4 cps, are small.

Closure to “Sand Liquefaction Under Cyclic Loading Simple Shear Conditions”

Investigation of nonlinear wave-induced seabed response around mono-pile foundation

A new analytical solution for wave scattering by a submerged horizontal porous plate with finite thickness

SPH numerical modeling of wave–perforated breakwater interaction

This paper summarizes the results of an experimental study directed towards the validation of a mathematical model for the buildup of pore water pressure and resulting liquefaction of marine soils under progressive waves. Experiments were conducted under controlled conditions with silt (d50 D 00070 mm) in a wave flume with a soil pit. Waves with wave heights in the range of 7.7‐18 cm, 55-cm water depth and 1.6-s wave period enabled us to study both the liquefaction and no-liquefaction regime pore water pressure buildup. The experimental data were used to validate the model. A numerical example is also included in the paper to demonstrate the implementation of the model for real-life scenarios.

Experimental Validation of a Mathematical Model For Seabed Liquefaction Under Waves

This paper presents the results of an experimental study of the seabed liquefaction beneath standing waves. Silt (with d50=0.070 mm) was used in the experiments. Two kinds of measurements were carried out: pore water pressure measurements and water surface elevation measurements. These measurements were synchronized with video recording of the liquefaction process from the side. The ranges of the various quantities in the experiments were wave height H=5.9–12.0 cm, wave period T=1.09 s, and water depth h=30 cm. The experiments show that the seabed liquefaction under standing waves, although qualitatively similar, show features different from that caused by progressive waves. The pore water pressure builds up (or accumulated) in the areas around the node and subsequently spreads out toward the antinodes. The experimental results imply that this transport is caused by a diffusion mechanism with a diffusion coefficient equal to the coefficient of consolidation. The experiments further show that the n...

Residual liquefaction of seabed under standing waves

Clear water scour around a finite array of cylinders

Scour patterns around isolated vegetation elements

This paper presents the results of an experimental study of the influence of clay content (CC) on liquefaction of seabed beneath progressive waves. Experiments were, for the most part, conducted with silt and silt-clay mixtures; in supplementary tests, sand-clay mixtures were used. Two types of measurements were carried out: (1) pore-water pressure measurements across the soil depth and (2) water-surface elevation measurements. These measurements were synchronized with video recordings of the liquefaction process from the side. The ranges of the various quantities in the experiments were wave height H=7.6−18.3 cm, wave period T=1.6 s, and water depth h=55 cm. The experiments showed that the influence of CC on wave-induced liquefaction is very significant. Susceptibility of silt to liquefaction was increased with increasing CC up to CC≈30% (which is clay-specific), beyond which the mixture of silt and clay was not liquefied. Sand may become prone to liquefaction with the introduction of clay, contr...

V.S. Ozgur Kirca

Papers

Experimental Validation of a Mathematical Model For Seabed Liquefaction Under Waves

Residual liquefaction of seabed under standing waves

Clear water scour around a finite array of cylinders

Scour patterns around isolated vegetation elements

Influence of Clay Content on Wave-Induced Liquefaction