A semi-analytical solution for random wave-induced soil response and seabed liquefaction in marine sediments

2007 ◽  
Vol 34 (8-9) ◽  
pp. 1211-1224 ◽  
Author(s):  
Haijiang Liu ◽  
Dong-Sheng Jeng
Keyword(s):  
Analytical Solution ◽  
Marine Sediments ◽  
Random Wave ◽  
Soil Response ◽  
Wave Induced

Response of a Porous Seabed Under Random Wave Loading

2006 ◽  
Author(s):  
Haijiang Liu ◽  
Dong-S. Jeng
Keyword(s):  
Soil Parameters ◽  
Random Wave ◽  
Wave Loading ◽  
Random Waves ◽  
Regular Waves ◽  
Offshore Pipelines ◽  
Soil Response ◽  
Significant Difference ◽  
Wave Induced ◽  
Soil Responses

The evaluation of the wave-induced soil response is particularly important for many coastal engineering installations such as offshore pipelines, platforms and breakwaters. Most previous investigations have been limited to the linear regular wave loading, even though the real situation is under random waves. In this study, we propose a semi-analytical solution for the random wave-induced pore pressure and effective stresses in marine sediments. Based on the new analytical solutions, different soil responses under the random wave loading are investigated and compared with the corresponding results under the linear regular waves. Numerical examples demonstrate the significant difference on wave-induced seabed response between these two wave loadings due to the irregularity introduced by the random waves. Finally, the influence of several soil parameters on the soil response under random wave loading is also examined.

scholarly journals Random Wave-Induced Momentary Liquefaction around Rubble Mound Breakwaters with Submerged Berms

2020 ◽  
Vol 8 (5) ◽  
pp. 338
Author(s):  
Daniele Celli ◽  
Yuzhu Li ◽  
Muk Chen Ong ◽  
Marcello Di Risio
Keyword(s):  
Irregular Waves ◽  
Random Wave ◽  
Random Waves ◽  
Regular Waves ◽  
Peak Period ◽  
Soil Response ◽  
Minimum Number ◽  
Rubble Mound ◽  
Wave Induced ◽  
Rubble Mound Breakwaters

The effects of submerged berms in attenuating the momentary liquefaction beneath rubble mound breakwaters under regular waves were investigated in a recent study. The present work aims to investigate the momentary liquefaction probabilities around and beneath breakwaters with submerged berms under random waves. The interaction between waves and breakwaters with submerged berms has been simulated through a phase-resolving numerical model. The soil response to the seabed pressure induced by random waves has been investigated using a poro-elastic soil solver. For three different breakwater configurations, the liquefaction depths under random wave conditions have been compared with those cases under representative regular waves. In the present study, the offshore spectral wave height ( H m 0 ) and the peak period ( T p ) of irregular waves are used as representative regular wave parameters. Results reveal the importance of considering random waves for a safe estimation of the momentary liquefaction probability. Indication about the minimum number of random waves, which is required to properly catch the liquefaction occurrences, has been also addressed.

Evaluation of Seismic Simplified Methods for Deep Circular Tunnel

2011 ◽  
Vol 261-263 ◽  
pp. 1862-1866
Author(s):  
Zheng Fang Dong ◽  
Yi Chao Yao ◽  
Jun Jie Wang
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Analytical Solution ◽  
Displacement Method ◽  
Circular Tunnel ◽  
Variable Theory ◽  
Soil Response ◽  
Complex Variable Theory ◽  
Spring Coefficient ◽  
Deep Circular Tunnel

Firstly several seismic simplified methods commonly used for deep circular tunnel are evaluated and the difficulties in response displacement method are pointed out. Then the analytical solution of soil spring coefficient and soil response of deep circular tunnel is derived from using complex variable theory of planar elastic theory based on pseudo-static hypothesis. The analytical solution has been verified by comparing its predictions with results from an analysis in finite element method. It is concluded that the analytical solution can be regarded as one feasible reference for the simplification of response displacement method.

NUMERICAL MODELLING OF WAVE-INDUCED SOIL RESPONSE AROUND BREAKWATER HEADS

2011 ◽  
pp. 789-796
Author(s):  
D.-S. JENG ◽  
Y. ZHANG ◽  
J.-S. ZHANG ◽  
C. ZHANG ◽  
P. L.-F. LIU
Keyword(s):  
Numerical Modelling ◽  
Soil Response ◽  
Wave Induced

scholarly journals Random wave-driven drag forces on near-bed vegetation in shallow water based on deepwater wind conditions

2019 ◽  
Vol 233 (4) ◽  
pp. 1287-1290
Author(s):  
Dag Myrhaug
Keyword(s):  
Shallow Water ◽  
Drag Force ◽  
Wind Waves ◽  
Wave Spectrum ◽  
Random Wave ◽  
Random Waves ◽  
Coastal Zones ◽  
Drag Forces ◽  
Mean Wind Speed ◽  
Wave Induced

This article provides a simple analytical method for giving estimates of random wave-driven drag forces on near-bed vegetation in shallow water from deepwater wind conditions. Results are exemplified using a Pierson–Moskowitz model wave spectrum for wind waves with the mean wind speed at the 10 m elevation above the sea surface as the parameter. The significant value of the drag force within a sea state of random waves is given, and an example typical for field conditions is presented. This method should serve as a useful tool for assessing random wave-induced drag force on vegetation in coastal zones and estuaries based on input from deepwater wind conditions.

Impact of fluid saturation on the reflection coefficient of a poroelastic layer

Geophysics ◽  
2011 ◽  
Vol 76 (2) ◽  
pp. N1-N12 ◽  
Author(s):  
Beatriz Quintal ◽  
Stefan M. Schmalholz ◽  
Yuri Y. Podladchikov
Keyword(s):  
Fluid Flow ◽  
Reflection Coefficient ◽  
Analytical Solution ◽  
Quality Factor ◽  
Velocity Dispersion ◽  
Normal Incidence ◽  
Sand Layer ◽  
Partially Saturated ◽  
Fluid Saturation ◽  
Wave Induced

The impact of changes in saturation on the frequency-dependent reflection coefficient of a partially saturated layer was studied. Seismic attenuation and velocity dispersion in partially saturated (i.e., patchy saturated) poroelastic media were accounted for by using the analytical solution of the 1D White’s model for wave-induced fluid flow. White’s solution was applied in combination with an analytical solution for the normal-incidence reflection coefficient of an attenuating layer embedded in an elastic or attenuating background medium to investigate the effects of attenuation, velocity dispersion, and tuning on the reflection coefficient. Approximations for the frequency-dependent quality factor, its minimum value, and the frequency at which the minimum value of the quality factor occurs were derived. The approximations are valid for any two alternating sets of petrophysical parameters. An approximation for the normal-incidence reflection coefficient of an attenuating thin (compared to the wavelength) layer was also derived. This approximation gives insight into the influence of contrasts in acoustic impedance and/or attenuation on the reflectivity of a thin layer. Laboratory data for reflections from a water-saturated sand layer and from a dry sand layer were further fit with petrophysical parameters for unconsolidated sand partially saturated with water and air. The results showed that wave-induced fluid flow can explain low-frequency reflection anomalies, which are related to fluid saturation and can be observed in seismic field data. The results further indicate that reflection coefficients of partially saturated layers (e.g., hydrocarbon reservoirs) can vary significantly with frequency, especially at low seismic frequencies where partial saturation may often cause high attenuation.

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