scholarly journals Scour Protection of Submarine Pipelines Using Ionic Soil Stabilizer Solidified Soil

2022 ◽  
Vol 10 (1) ◽  
pp. 76
Author(s):  
Ruigeng Hu ◽  
Xiuhai Wang ◽  
Hongjun Liu ◽  
Hao Leng
Keyword(s):  
Soil Layer ◽  
Cohesive Soil ◽  
Protective Capacity ◽  
Soil Stabilizer ◽  
Flume Tests ◽  
Laboratory Flume ◽  
Scour Holes ◽  
Protection Layer ◽  
Ocean Environment ◽  
Scour Protection

A novel scour protection approach for pipeline using the Ionic Soil Stabilizer (ISS) solidified soil was proposed in this study. The ISS-solidified slurry can be poured adjacent to the pipeline immediately after it was placed, or in the growing scour holes. In the present study, the first type was utilized as the scour protection layer around the pipeline. A series of laboratory flume tests were conducted to validate the protective capacity of ISS-solidified slurry for the pipeline in waves and combined waves and current. Then, the scanning electron microscope (SEM) tests and pore size tests were carried out, respectively, to investigate the mechanism of ISS-solidified slurry for scour protection around the pipeline. Finally, the effects of the ISS-solidified layer for liquefaction stability of non-cohesive subsoil were evaluated. The results indicated that the ISS-solidified slurry is a reliable, economic approach for scour protection around pipelines in the ocean environment. It is noteworthy that if a non-cohesive soil layer underlies the ISS-solidified slurry, it is vulnerable to suffer accumulated liquefaction due to the dense crust structure of the ISS-solidified layer, so the adverse effects for accumulated liquefaction should be considered carefully due to the set of the ISS-solidified layer.

Erosion tests on four intact Ontario clays

1990 ◽  
Vol 27 (5) ◽  
pp. 692-696 ◽  
Author(s):  
J. W. Kamphuis ◽  
P. N. Gaskin ◽  
E. Hoogendoorn
Keyword(s):  
Soil Erosion ◽  
Key Words ◽  
Cohesive Soil ◽  
Shear Stresses ◽  
Cohesive Soils ◽  
Clear Water ◽  
Flume Test ◽  
Flume Tests ◽  
Laboratory Flume ◽  
Sand Particles

Erosion tests were carried out on four natural intact cohesive soils from Ontario using laboratory flume tests with both clear water and water with sand in suspension. It was found that erosion was initiated at discontinuities. The critical shear stresses were low and were not related to the geotechnical properties of the soils. Higher rates of erosion occurred with the sand suspension, and erosion appeared to be controlled by the movement of the sand particles. It is suggested that where the eroding water contains particles in suspension, such as in river beds and along shorelines of cohesive soil, erosion may be controlled by the size of the particles rather than the properties of the cohesive soil or the eroding water. Key words: erosion, cohesive soil, flume test.

HHT Analysis on Pore Pressure Dissipation of Wave-Induced Fluidization in a Sandy Bed

2011 ◽  
Author(s):  
Shiaw-Yih Tzang ◽  
Yung-Lung Chen ◽  
Shan-Hwei Ou
Keyword(s):  
Pore Pressure ◽  
Soil Layer ◽  
Excess Pore Pressure ◽  
Pressure Measurements ◽  
Flume Tests ◽  
Dissipation Mechanism ◽  
Frequency Components ◽  
Excess Pore Pressures ◽  
Wave Induced ◽  
Excess Pore

Wave-induced pore pressure variations during the stage of increasing excess pore pressure consist of the mechanism of generation of fluidization. Moreover, in post-fluidization stage, pore pressure variations not only reveal the dissipation mechanism of fluidization but also the wave-fluidized bed interactions. Past results from a series of lab flume tests have further illustrated that pore pressure variations in a fluidized response are nonlinear and nonsataionary. Hence, the HHT method was further applied to analyze the pore pressure measurements in this study. The results demonstrate that after the dissipation of excess pore pressures the amplitudes of fundamental and higher-frequency components begin to decay. Meanwhile, the amplified amplitudes of fundamental and higher-frequency components during fluidization response would decrease with decreasing thickness of fluidized soil-layer in consecutive tests.

Laboratory tests to study hydraulic fill

1992 ◽  
Vol 29 (3) ◽  
pp. 405-417 ◽  
Author(s):  
Angela A. G. Küpper ◽  
Norbert R. Morgenstern ◽  
David C. Sego
Keyword(s):  
Grain Size ◽  
Laboratory Tests ◽  
Constant Composition ◽  
Hydraulic Fill ◽  
Flume Tests ◽  
Experimental Apparatus ◽  
Mean Grain Size ◽  
Laboratory Flume ◽  
The Mean ◽  
Physical Phenomena

Laboratory flume deposition tests were carried out to study the physical phenomena associated with the deposition of a sand slurry to form a hydraulic fill. The experimental apparatus was carefully designed to minimize flume-wall effects on the flow and to allow discharge of slurry of constant composition for an indefinite period of time. Slurry concentration and flow rate were varied independently to study their effects on characteristics of the fill such as geometry, grain-size distribution, and density. Three different sands were used to evaluate the influence of the mean grain size. Key words : hydraulic fill, flume tests, sand, profile, slope, density.

Hydromechanics of submarine pipelines: design problems

1985 ◽  
Vol 12 (4) ◽  
pp. 863-874 ◽  
Author(s):  
John B. Herbich
Keyword(s):  
Field Measurements ◽  
External Pressure ◽  
Pressure Effects ◽  
Bottom Current ◽  
Wave Forces ◽  
Ocean Environment ◽  
Scour Protection ◽  
Hydrodynamic Wave ◽  
Pipeline Failures ◽  
Design And Construction

In recent years, the size, number, and applications of offshore pipelines have been steadily increasing. The design and construction of pipelines in offshore cold regions calls for special measures (such as deep burial) because of seabed scouring caused by ice.Various societies and associations have pointed out the deficiencies in the state-of-the-art areas of environmental, design, and construction factors, particularly those dealing with structural, external pressure effects, and depth of burial. It has also been recommended that more data be obtained in order to fully evaluate pipeline–soil interaction. Also, field measurements of velocities, accelerations, and forces causing scour around pipelines would greatly enhance our understanding of offshore pipeline behavior.Offshore pipelines fail in many different ways, and each mode of failure should be examined individually. Because of the complexity of the ocean environment it is quite difficult to evaluate pipeline failures in detail.Environmental factors such as hydrodynamic wave forces and currents, buoyancy forces due to liquefaction of sediment, and scouring potential are presented. The dynamics of scour, incipient sediment motion, depth of scour, and scour patterns around pipelines are also reviewed as well as the maximum scour depths as a function of bottom current velocity.Methods for scour protection in shallow and deep water are described as well as the need for inspection and maintenance to prevent failures. Key words: pipelines, offshore, hydrodynamic forces, cover, scour.

Influence of soil permeability on rainfall-induced flowslides in laboratory flume tests

2007 ◽  
Vol 44 (9) ◽  
pp. 1128-1136 ◽  
Author(s):  
Fawu Wang ◽  
Hiroki Shibata
Keyword(s):  
Significant Influence ◽  
Rainfall Intensity ◽  
Soil Permeability ◽  
Artificial Rainfall ◽  
Flume Tests ◽  
Laboratory Flume ◽  
Slope Condition ◽  
Model Slope ◽  
Different Soils

The mobility of flowslides is influenced by various factors. In this paper, laboratory flume tests were used to evaluate the influence of soil permeability using different soils with different permeabilities in a model slope, while keeping the slope condition and artificial rainfall intensity constant. It was found that the permeability of soil has a significant influence on the initialization of flowslides and that there is an optimal soil permeability existing for the mobility of flowslides when rainfall intensity is kept constant.

scholarly journals Simplified Probabilistic Analysis of Settlement of Cyclically Loaded Soil Stratum by Point Estimate Method

2016 ◽  
Vol 63 (2-3) ◽  
pp. 121-133 ◽  
Author(s):  
Jarosław Przewłócki ◽  
Jarosław Górski ◽  
Waldemar Świdziński
Keyword(s):  
Probabilistic Analysis ◽  
Soil Layer ◽  
Cohesive Soil ◽  
Point Estimate ◽  
Model Parameters ◽  
Soil Stratum ◽  
Point Estimate Method ◽  
Estimate Method ◽  
Soil Settlement ◽  
Simplified Algorithm

AbstractThe paper deals with the probabilistic analysis of the settlement of a non-cohesive soil layer subjected to cyclic loading. Originally, the settlement assessment is based on a deterministic compaction model, which requires integration of a set of differential equations. However, with the use of the Bessel functions, the settlement of a soil stratum can be calculated by a simplified algorithm. The compaction model parameters were determined for soil samples taken from subsoil near the Izmit Bay, Turkey. The computations were performed for various sets of random variables. The point estimate method was applied, and the results were verified by the Monte Carlo method. The outcome leads to a conclusion that can be useful in the prediction of soil settlement under seismic loading.

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