Transition of soil friction during suction pile installation

2002 ◽  
Vol 39 (5) ◽  
pp. 1118-1125 ◽  
Author(s):  
Y Cho ◽  
S Bang ◽  
T Preber
Keyword(s):  
Soil Properties ◽  
Friction Angle ◽  
Soil Strength ◽  
Model Tests ◽  
Laboratory Model ◽  
Suction Pressure ◽  
Pile Installation ◽  
Nondimensional Parameter ◽  
Pile Penetration ◽  
The Relationship

A series of laboratory model tests on the suction pile installation in sand have been conducted to obtain the relationship between the applied suction pressure inside the pile and the resulting pile penetration. The relationships have been used to estimate the mobilized soil strength during the pile installation. This reduction in the soil strength due to the applied suction pressure is described as a function of a nondimensional parameter to characterize the variation and transition of the soil strength during the pile installation. The nondimensional parameter includes all pertinent pile and soil properties that are thought to affect the behavior of the suction pile during installation.Key words: suction pile, suction pressure, mobilized effective soil friction angle.

Calibration of Mobilized Soil Strength During Installation of Suction Piles

2006 ◽  
Author(s):  
E. C. Burg ◽  
B. A. Frankl ◽  
L. M. Metz ◽  
S. Bang
Keyword(s):  
Soil Strength ◽  
Suction Pressure ◽  
Lateral Loads ◽  
Dimensional Parameter ◽  
Pile Installation ◽  
Strength Variation ◽  
Pile Penetration ◽  
Southern Korea

An innovative breakwater system has been introduced for use in areas with thick soft seafloor, utilizing suction piles as the foundations. Gravity-type concrete caissons are placed on top, which resist the lateral loads caused by the wind and waves to protect the harbor behind. In Dec. 2004, four large concrete suction piles were prefabricated and installed successfully in southern Korea. During the installation of suction piles, detailed measurements were made on one pile, including the suction pressure vs. pile penetration relationship. They were used to estimate the mobilized soil strength during the suction pile installation. The calculated mobilized soil strength variation was then expressed as a function of a non-dimensional parameter that included the most essential parameters governing the behavior of suction piles during installation.

On the response of fluidized piles from laboratory model tests in granular soils

2014 ◽  
Vol 1 (2) ◽  
pp. 69-81 ◽  
Author(s):  
F. Schnaid ◽  
L. Passini ◽  
F. Stracke ◽  
S. Mezzomo
Keyword(s):  
Limit Equilibrium ◽  
Horizontal Stress ◽  
Design Guidelines ◽  
Model Tests ◽  
Equilibrium Analysis ◽  
Laboratory Model ◽  
Limit Equilibrium Analysis ◽  
Pile Installation ◽  
Water Jets ◽  
Constitutive Parameters

Design guidelines of foundation anchors and piles embedded in fluidized sand comprises understanding of installation processes, defining constitutive parameters and establishing analysis techniques. These fundamental aspects have been investigated by a series of laboratory model tests designed to evaluate the mechanism taking place during pile installation through the influence of downwardly-directed vertical water jets in the geometry of fluidized cavities in saturated sands. Measurements indicate fluidization geometry to be controlled by combined effects of jet velocity and the ratio of particle and jet diameters which can be conveniently expressed by the Froude number of particles. Characteristics of the fluidized zone geometry prior and after fluidization indicate considerable reduction of relative density of fluidized samples. Limit equilibrium analysis using geotechnical parameters approaching critical state provided indicative horizontal stress levels to estimate the uplift skin friction of model steel piles.

Experimental Investigation of Pile Installation by Vertical Jet Fluidization in Sand

2015 ◽  
Vol 137 (4) ◽  
Author(s):  
Larissa de Brum Passini ◽  
Fernando Schnaid
Keyword(s):  
Flow Rate ◽  
Initial Density ◽  
Model Tests ◽  
Laboratory Model ◽  
Embedment Depth ◽  
Pile Installation ◽  
Pile Diameter ◽  
Fluid Properties ◽  
Constitutive Parameters ◽  
Vertical Jet

The paper examines the mechanism of pile installation by vertical jet fluidization in saturated sand in order to define the constitutive parameters that control installation geometry and pile depth of embedment. A series of laboratory model tests representative of offshore torpedo piles was carried out using downwardly directed vertical water jets in both medium and dense sands. Measurements from model tests at three different scales indicate that the geometry of fluidized cavities is not influenced by the initial density of the sand and that the perturbed zone is constrained to a distance of about two pile diameters from the pile centerline during pile installation. Following the laws of dimensional analysis, an expression for the embedment of fluidized piles is derived and shows that penetration depth is a function of pile weight and geometry, fluidized water jet flow rate and velocity, as well as the soil and fluid properties. Penetration is shown to increase with increasing flow rate and pile weight and decreasing soil relative density. Although the results have to be validated by tests at larger scales to prove compatibility with the full-scale behavior, model tests indicate maximum embedment depth of the order of 50 times the pile diameter.

scholarly journals Soil Nutrient and Vegetation Diversity Patterns of Alpine Wetlands on the Qinghai-Tibetan Plateau

2021 ◽  
Vol 13 (11) ◽  
pp. 6221
Author(s):  
Muyuan Ma ◽  
Yaojun Zhu ◽  
Yuanyun Wei ◽  
Nana Zhao
Keyword(s):  
Species Diversity ◽  
Tibetan Plateau ◽  
Soil Properties ◽  
Soil Ph ◽  
Plant Biomass ◽  
Principal Component ◽  
Vegetation Diversity ◽  
Vegetation Biomass ◽  
Relative Contribution ◽  
The Relationship

To predict the consequences of environmental change on the biodiversity of alpine wetlands, it is necessary to understand the relationship between soil properties and vegetation biodiversity. In this study, we investigated spatial patterns of aboveground vegetation biomass, cover, species diversity, and their relationships with soil properties in the alpine wetlands of the Gannan Tibetan Autonomous Prefecture of on the Qinghai-Tibetan Plateau, China. Furthermore, the relative contribution of soil properties to vegetation biomass, cover, and species diversity were compared using principal component analysis and multiple regression analysis. Generally, the relationship between plant biomass, coverage, diversity, and soil nutrients was linear or unimodal. Soil pH, bulk density and organic carbon were also significantly correlated to plant diversity. The soil attributes differed in their relative contribution to changes in plant productivity and diversity. pH had the highest contribution to vegetation biomass and species richness, while total nitrogen was the highest contributor to vegetation cover and nitrogen–phosphorus ratio (N:P) was the highest contributor to diversity. Both vegetation productivity and diversity were closely related to soil properties, and soil pH and the N:P ratio play particularly important roles in wetland vegetation biomass, cover, and diversity.

Laboratory Model Tests on Dredger Fills by Vacuum Preloading with No Sand Cushion

2012 ◽  
Vol 170-173 ◽  
pp. 655-660
Author(s):  
Ya Jun Wu ◽  
Jian Bo Yang
Keyword(s):  
Fine Particles ◽  
Soil Strength ◽  
Plasticity Index ◽  
Laboratory Model ◽  
Soil Parameters ◽  
Grain Composition ◽  
Vacuum Preloading ◽  
Prefabricated Vertical Drains ◽  
Water Contents ◽  
Sand Cushion

It is difficult to operate on the hydraulic-filled mucky soil foundation which the water content is high, so the vacuum preloading method with no sand cushion is used to deal with the foundation in some areas in China. Although there are still many problems in it’s application, such as, the effective range of the prefabricated vertical drains(PVDs) is small, the surrounding soil is easy to be accumulated and the soil strength increases little. For these problems, a laboratory model test on dredger fills made from the 4th layer of the Shanghai mucky soil by vacuum preloading with no sand cushion is performed. The changes and distributions in the settlement, water contents, permeability, plasticity index and grain composition of the dredger fill are studied in the process of the vacuum preloading. It is found that the water contents and permeability of the soft clay near the PVD (the diameter is about 40 to 50cm) are much lower than the outside, while the content of fine particles, plasticity index and soil strength near the PVD is much higher than the others. The measured data shows that the fine particles gather to a soil column at the center of the PVD under the action of vacuum negative pressure, then the permeability and the grain composition of the soil around the PVD is changed. As a result, soil parameters are not evenly distributed. Finally, some suggestions about how to reduce the non-uniformity are proposed.

Profile Soil Property Estimation Using a VIS-NIR-EC-Force Probe

2017 ◽  
Vol 60 (3) ◽  
pp. 683-692 ◽  
Author(s):  
Yongjin Cho ◽  
Kenneth A. Sudduth ◽  
Scott T. Drummond
Keyword(s):  
Soil Properties ◽  
Water Content ◽  
Bulk Density ◽  
Soil Property ◽  
Soil Strength ◽  
Reflectance Spectra ◽  
Land Resource ◽  
Strength Data ◽  
Soil Sensors ◽  
Combining Data

Abstract. Combining data collected in-field from multiple soil sensors has the potential to improve the efficiency and accuracy of soil property estimates. Optical diffuse reflectance spectroscopy (DRS) has been used to estimate many important soil properties, such as soil carbon, water content, and texture. Other common soil sensors include penetrometers that measure soil strength and apparent electrical conductivity (ECa) sensors. Previous field research has related these sensor measurements to soil properties such as bulk density, water content, and texture. A commercial instrument that can simultaneously collect reflectance spectra, ECa, and soil strength data is now available. The objective of this research was to relate laboratory-measured soil properties, including bulk density (BD), total organic carbon (TOC), water content (WC), and texture fractions to sensor data from this instrument. At four field sites in mid-Missouri, profile sensor measurements were obtained to 0.9 m depth, followed by collection of soil cores at each site for laboratory measurements. Using only DRS data, BD, TOC, and WC were not well-estimated (R2 = 0.32, 0.67, and 0.40, respectively). Adding ECa and soil strength data provided only a slight improvement in WC estimation (R2 = 0.47) and little to no improvement in BD and TOC estimation. When data were analyzed separately by major land resource area (MLRA), fusion of data from all sensors improved soil texture fraction estimates. The largest improvement compared to reflectance alone was for MLRA 115B, where estimation errors for the various soil properties were reduced by approximately 14% to 26%. This study showed promise for in-field sensor measurement of some soil properties. Additional field data collection and model development are needed for those soil properties for which a combination of data from multiple sensors is required. Keywords: NIR spectroscopy, Precision agriculture, Reflectance spectra, Soil properties, Soil sensing.

scholarly journals AN INVESTIGATION ON THE EFFECTS OF MICRO-PARAMETERS ON THE STRENGTH PROPERTIES OF ROCK

2021 ◽  
Vol 36 (1) ◽  
pp. 111-119
Author(s):  
Behzad Jafari Mohammadabadi ◽  
Kourosh Shahriar ◽  
Hossein Jalalifar ◽  
Kaveh Ahangari
Keyword(s):  
Mechanical Properties ◽  
Numerical Simulation ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Friction Coefficient ◽  
Critical Stress ◽  
Friction Angle ◽  
Strength Properties ◽  
Brazilian Tensile Strength ◽  
The Relationship

Rocks are formed from particles and the interaction between those particles controls the behaviour of a rock’s mechanical properties. Since it is very important to conduct extensive studies about the relationship between the micro-parameters and macro-parameters of rock, this paper investigates the effects of some micro-parameters on strength properties and the behaviour of cracks in rock. This is carried out by using numerical simulation of an extensive series of Uniaxial Compressive Strength (UCS) and Brazilian Tensile Strength (BTS) tests. The micro-parameters included the particles’ contact modulus, the contact stiff ness ratio, bond cohesion, bond tensile strength, the friction coefficient and the friction angle, and the mechanical properties of chromite rock have been considered as base values of the investigation. Based on the obtained results, it was found that the most important micro-parameters on the behaviour of rock in the compressive state are bond cohesion, bond tensile strength, and the friction coefficient. Also, the bond tensile strength showed the largest effect under tensile conditions. The micro-parameter of bond tensile strength increased the rock tensile strength (up to 5 times), minimized destructive cracks and increased the corresponding strain (almost 2.5 times) during critical stress.

scholarly journals Probabilistic Bearing Capacity of a Pavement Resting on Fibre Reinforced Embankment Considering Soil Spatial Variability

2021 ◽  
Vol 7 ◽  
Author(s):  
Kouseya Choudhuri ◽  
Debarghya Chakraborty
Keyword(s):  
Spatial Variability ◽  
Soil Properties ◽  
Bearing Capacity ◽  
Coefficient Of Variation ◽  
Friction Angle ◽  
Horizontal Scale ◽  
Vertical Scale ◽  
Scale Of Fluctuation ◽  
The Mean ◽  
The Finite Difference Method

This paper intends to examine the influence of spatial variability of soil properties on the probabilistic bearing capacity of a pavement located on the crest of a fibre reinforced embankment. An anisotropic random field, in combination with the finite difference method, is used to carry out the probabilistic analyses. The cohesion and internal friction angle of the soil are assumed to be lognormally distributed. The Monte Carlo simulations are carried out to obtain the mean and coefficient of variation of the pavement bearing capacity. The mean bearing capacity of the pavement is found to decrease with the increase in horizontal scale of fluctuation for a constant vertical scale of fluctuation; whereas, the coefficient of variation of the bearing capacity increases with the increase in horizontal scale of fluctuation. However, both the mean and coefficient of variation of bearing capacity of the pavement are observed to be increasing with the increase in vertical scale of fluctuation for a constant horizontal scale of fluctuation. Apart from the different scales of fluctuation, the effects of out of the plane length of the embankment and randomness in soil properties on the probabilistic bearing capacity are also investigated in the present study.

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