Development and Sea Test Results of a Deep-Sea Tsunami Warning Buoy System

2019 ◽  
Vol 53 (3) ◽  
pp. 6-15
Author(s):  
Yi Zhang ◽  
Hongmei Shang ◽  
Xiaojuan Zhang ◽  
Wei Ren
Keyword(s):  
Deep Sea ◽  
Water Pressure ◽  
Ocean Waves ◽  
Tsunami Warning ◽  
False Alarms ◽  
Underwater Acoustic Communications ◽  
Test Results ◽  
Tsunami Waves ◽  
Tidal Waves ◽  
Tsunami Detection

AbstractTsunamis are catastrophic ocean waves that could cause devastating damage to human lives, properties, and coastal infrastructures. This article presents the design and sea test results of a deep-sea tsunami warning buoy system. The system consists of a seafloor tsunami detection subsystem and a surface buoy. The tsunami detection subsystem monitors the tsunami waves through seafloor water pressure measurement. Detection of tsunami waves is achieved by separating the influence of astronomical tidal waves from the seafloor measurements via a cubic polynomial extrapolation method. The deep seafloor measurements and the tsunami detection results are transmitted in real time from the seafloor subsystem to the surface buoy via underwater acoustic communications; the buoy then relays the data to an onshore tsunami warning center via satellite links. The tsunami warning buoy system was evaluated in four deep-sea tests at different locations. In the last sea test, the system achieved an effective working duration of 108 consecutive days. This article analyzes the causes of false alarms and data transmission failures in the sea tests and puts forward effective solutions for system improvement. The system design and the sea test results could serve as references for future development of deep-sea infrastructures.

scholarly journals Perbandingan Pengujian Konsolidasi Menggunakan Alat Rowe Cell dan Oedometer pada Tanah Lanau Lunak

2020 ◽  
Vol 22 (2) ◽  
pp. 149-155
Author(s):  
Iskandar ◽  
Rabiya
Keyword(s):  
Pore Water Pressure ◽  
Water Pressure ◽  
Soft Soil ◽  
Soil Samples ◽  
Soil Parameters ◽  
Soil Consolidation ◽  
Test Results ◽  
Soft Soils ◽  
Better Than ◽  
Rowe Cell

Soil consolidation testing using an oedometer and rowe cell. Oedometers are often used on clay and soft soils. However, in the development of the rowe cell device, the results of lowering soft soil were better than the oedometer. The advantage of this rowe cell is that it can determine the saturation value of the soil samples tested. The rowe cell tester can measure the pore water pressure at the beginning and end of each consolidation stage. This rowe cell can provide suitable settlement for soft soils. This consolidation test to obtain soil parameters such as Cv and Cc by using the rowe cell tool. After that, from the test results, the two tools were compared.

Applied Research on Dynamic Replacement Method in Tailings Residue Subgrade Reinforcement

2013 ◽  
Vol 639-640 ◽  
pp. 943-946
Author(s):  
Jiao Long He ◽  
Yong Zhou ◽  
Zhong Ai Jiang
Keyword(s):  
Applied Research ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Field Testing ◽  
Standard Penetration Test ◽  
Load Test ◽  
Test Results ◽  
Replacement Method ◽  
Dynamic Replacement ◽  
Testing Experiment

Based on the reinforcing mechanism of dynamic replacement method ,this article put forward the construction parameters and measures of dynamic replacement method , combining with the result of actual engineering field testing experiment. The field load test, standard penetration test and pore water pressure test results show that the characteristic value of subgrade bearing capacity is more than 130 kpa when the tailings residue subgrade has been managed with dynamic replacement method, providing references for applied research on dynamic replacement method in tailings residue subgrade reinforcement.

scholarly journals Meteotsunamis: atmospherically induced destructive ocean waves in the tsunami frequency band

2006 ◽  
Vol 6 (6) ◽  
pp. 1035-1051 ◽  
Author(s):  
S. Monserrat ◽  
I. Vilibić ◽  
A. B. Rabinovich
Keyword(s):  
Gravity Waves ◽  
Spatial Scales ◽  
World Ocean ◽  
Ocean Waves ◽  
Tsunami Waves ◽  
Atmospheric Disturbances ◽  
Source Mechanisms ◽  
Low Probability ◽  
Atmospheric Gravity ◽  
Meteorological Tsunamis

Abstract. In light of the recent enhanced activity in the study of tsunami waves and their source mechanisms, we consider tsunami-like waves that are induced by atmospheric processes rather than by seismic sources. These waves are mainly associated with atmospheric gravity waves, pressure jumps, frontal passages, squalls and other types of atmospheric disturbances, which normally generate barotropic ocean waves in the open ocean and amplify them near the coast through specific resonance mechanisms (Proudman, Greenspan, shelf, harbour). The main purpose of the present study is to describe this hazardous phenomenon, to show similarities and differences between seismic and meteorological tsunamis and to provide an overview of meteorological tsunamis in the World Ocean. It is shown that tsunamis and meteotsunamis have the same periods, same spatial scales, similar physical properties and affect the coast in a comparably destructive way. Some specific features of meteotsunamis make them akin to landslide-generated tsunamis. The generation efficiency of both phenomena depend on the Froude number (Fr), with resonance taking place when Fr~1.0. Meteotsunamis are much less energetic than seismic tsunamis and that is why they are always local, while seismic tsunamis can have globally destructive effects. Destructive meteotsunamis are always the result of a combination of several resonant factors; the low probability of such a combination is the main reason why major meteotsunamis are infrequent and observed only at some specific locations in the ocean.

scholarly journals Impact of the moisture content in medium sands on CPTU test results

2016 ◽  
Vol 48 (3) ◽  
pp. 221-231 ◽  
Author(s):  
Łukasz Zawadzki ◽  
Marek Bajda
Keyword(s):  
Moisture Content ◽  
Unsaturated Soils ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Degree Of Saturation ◽  
Test Results ◽  
Time Dynamic ◽  
Tip Resistance ◽  
The Impact ◽  
Resistance Value

Abstract Soils occurring in the soil “active zone” are in contact with the surface and are directly influenced by external factors (mainly climatic changes) that cause variation in their parameters over time. Dynamic and uncontrolled changes of soil properties e.g. due to rainfall and evapotranspiration processes may affect field test results leading to the misinterpretation of the obtained data. This paper presents investigations on the influence of moisture content changes in sandy soils on CPTU results. For this purpose, a field ground model has been constructed and five CPTU tests with a different moisture content of soil were carried out. During the investigations, the tip resistance (qc), friction on sleeve (fs), and pore water pressure (u2) were measured. Moreover, a TDR probe was applied to determine the distribution of the moisture content in the studied soil columns. Differences between CPT results obtained in saturated and unsaturated soils have been shown. Furthermore, a simple equation to correct the tip resistance value due to the impact of the degree of saturation has been proposed.

Tsunamis

2017 ◽  
Author(s):  
John A. Adam
Keyword(s):  
Mathematical Model ◽  
Large Scale ◽  
Volcanic Eruptions ◽  
Ocean Waves ◽  
The Other ◽  
Tsunami Generation ◽  
Sea Waves ◽  
Tsunami Propagation ◽  
Tidal Waves ◽  
Special Cases

This chapter describes a mathematical model of tsunami propagation (transient waves). A tsunami is a series of ocean waves triggered by large-scale disturbances of the ocean, including earthquakes, as well as landslides, volcanic eruptions, and meteorites. Tsunamis have very long wavelengths (typically hundreds of kilometers). They have also been called “tidal waves” or “seismic sea waves,” but both terms are misleading. The chapter first considers the boundary-value problem before modeling two special cases of tsunami generation, one due to an initial displacement on the free surface and the other due to tilting of the seafloor. It also discusses surface waves on deep water and how fast the wave energy propagates and concludes with an analysis of leading waves due to a transient disturbance.

Improving engineering properties of mature fine tailings using Tubifex

2020 ◽  
Vol 47 (7) ◽  
pp. 812-821
Author(s):  
Xiaojuan Yang ◽  
Miguel de Lucas Pardo ◽  
Maria Ibanez ◽  
Lijun Deng ◽  
Luca Sittoni ◽  
...  
Keyword(s):  
Survival Rate ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Engineering Properties ◽  
Test Results ◽  
Sulfate Content ◽  
Mature Fine Tailings ◽  
Fine Tailings ◽  
The Mean ◽  
Solids Content

The present study investigated the effects of Tubifex (Oligochaeta: Tubificidae) treatment on the dewatering process of mature fine tailings (MFT). Experiments testing the survival rate showed that Tubifex can survive at 20 °C and 4 °C. MFT with initial solids content (Sc) of 30% of total mass were treated in 11 settling columns by three Tubifex densities, 1400, 2000 and 4200 individuals·m−2. Test results showed that the mean survival rate at 20 °C and 4 °C on the 28th day stayed around 85%. Tubifex enhanced MFT dewatering by providing compacted tailings with 11.6% and 66.7% higher Sc and undrained shear strength compared with nontreated tailings. Tubifex accelerated pore water pressure dissipation. Tubifex did not affect the chemical composition of tailings except for a decrease in sulfate content. The Sc of tailings treated by Tubifex increased by 67.4% within nine months, which was 129% greater than the Sc increase of the nontreated tailings after 11 months.

scholarly journals Tsunami Intrusion and River Ice Movement

Water ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 1290 ◽  
Author(s):  
Jiajia Pan ◽  
Hung Tao Shen
Keyword(s):  
Wave Propagation ◽  
Tsunami Wave ◽  
Water Pressure ◽  
Time Integration ◽  
Boussinesq Equations ◽  
Wave Model ◽  
Hybrid Technique ◽  
Ice Dynamics ◽  
Tsunami Waves ◽  
Surface Ice

A two-dimensional wave model coupled with ice dynamics is developed to evaluate ice effects on shallow water wave propagation on a beach and in a channel. The nonlinear Boussinesq equations with ice effects are derived and solved by the hybrid technique of the Godunov-type finite volume method and finite difference method with the third-order Runge–Kutta method for time integration. The shock capturing method enables the model to simulate complex flows over irregular topography. The model is capable of simulating wave propagations accurately, including non-hydrostatic water pressure and wave dispersions. The ice dynamic module utilizes a Lagrangian discrete parcel method, based on smoothed particle hydrodynamics. The Boussinesq wave model is validated with an analytical solution of water surface oscillation in a parabolic container, an analytical solitary wave propagation in a flat channel, and experimental data on tsunami wave propagations. The validated model is then applied to investigate the interaction between ice and tsunami wave propagation, in terms of ice attenuation on tsunami wave propagations over a beach, ice deposition on the beach driven by the tsunami wave, and ice jam formation and release in a coastal channel with the intrusion of the tsunami wave. The simulated results demonstrated the interactions between tsunami waves and surface ice, including the maximum run up, ice movement along the beach, and ice jamming in a channel.

scholarly journals Deep Learning-Based Timing Offset Estimation for Deep-Sea Vertical Underwater Acoustic Communications

2020 ◽  
Vol 10 (23) ◽  
pp. 8651
Author(s):  
Yanbo Wu ◽  
Yan Yao ◽  
Ning Wang ◽  
Min Zhu
Keyword(s):  
Deep Sea ◽  
Underwater Acoustic Communications ◽  
Acoustic Communications ◽  
Adaptive Equalizer ◽  
Random Surface ◽  
Wind Speeds ◽  
Timing Offset ◽  
Lower Complexity ◽  
Time Invariant ◽  
Height Model

This study proposes a novel receiver structure for underwater vertical acoustic communication in which the bias in the correlation-based estimation for the timing offset is learned and then estimated by a deep neural network (DNN) to an accuracy that renders subsequent use of equalizers unnecessary. For a duration of 7 s, 15 timing offsets of the linear frequency modulation (LFM) signals obtained by the correlation were fed into the DNN. The model was based on the Pierson–Moskowitz (PM) random surface height model with a moderate wind speed and was further verified under various wind speeds and experimental waveforms. This receiver, embedded with the DNN model, demonstrated lower complexity and better performance than the adaptive equalizer-based receiver. The 5000 m depth deep-sea experimental data show the superiority of the proposed combination of DNN-based synchronization and the time-invariant equalizer.

scholarly journals Test Study on Airtight Capability of Filter Cakes for Slurry Shield and Its Application in a Case

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Fanlu Min ◽  
Wei Zhu ◽  
Shengquan Xia ◽  
Rui Wang ◽  
Daiwei Wei ◽  
...  
Keyword(s):  
Yangtze River ◽  
Filter Cake ◽  
Water Pressure ◽  
Air Pressure ◽  
Test Results ◽  
Test Study ◽  
Capillary Bundle ◽  
Slurry Shield ◽  
Filter Cakes ◽  
The Relationship

To learn the airproof capacity of filter cakes as opening chambers under air pressure, a series of tests were carried out. The variations of discharged water with air pressure and time were observed, and the relationship between airproof capacity of filter cakes and surrounding air pressure was analysed. The test results indicated that there were three stages as compressed air acting on filter cakes: completely not infiltration, a very small amount of infiltration, and penetration leakage. The certain air pressure between the first and second stages was called the airproofing value of filter cake. And a capillary bundle model was used to explain the mechanism of air tightness of filter cakes. In Nanjing Yangtze River Tunnel, a 5 cm thickness filter cake was formed in gravel sand, and its airproofing value was a little lower than 0.12 MPa. The air pressure used as opening chamber should be equal to the summation of water pressure in sand and airproofing value of filter cake. While the air pressure is larger than the summation, the filter cake would be gas permeable. The slurry formulation and airproofing value of filter cakes obtained in the tests were applied successfully in Nanjing Yangtze River Tunnel.

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