Effective soil-stiffness validation: Shaker excitation of an in-situ monopile foundation

2017 ◽  
Vol 102 ◽  
pp. 241-262 ◽  
Author(s):  
W.G. Versteijlen ◽  
F.W. Renting ◽  
P.L.C. van der Valk ◽  
J. Bongers ◽  
K.N. van Dalen ◽  
...  
Keyword(s):  
Soil Stiffness

scholarly journals Determination of p-y curves for offshore piles based on in-situ soil investigations

2018 ◽  
Vol 219 ◽  
pp. 05003
Author(s):  
Kamila Międlarz ◽  
Lech Bałachowski
Keyword(s):  
Field Tests ◽  
Soil Parameters ◽  
Lateral Loads ◽  
Cohesionless Soils ◽  
In Situ Tests ◽  
Soil Stiffness ◽  
Soil Response ◽  
Direct Design ◽  
Offshore Piles

Offshore piles are subjected to complex loads with considerable lateral component. The pile-soil response to lateral loads can be described with the p-y method. For a given depth the load–deflection relationship is built to simulate the surrounding soil stiffness. This state-of-art paper presents a brief discussion of determination methods for the p-y curves using a standard approach based on the soil parameters derived from laboratory and in-situ tests or directly from field tests. The basic relationships for both cohesive and cohesionless soils are discussed. The advantage of direct design methods to describe the p-y curve relies in the reduction of necessary laboratory tests.

scholarly journals Characterizing Soil Stiffness Using Thermal Remote Sensing and Machine Learning

2021 ◽  
Vol 13 (12) ◽  
pp. 2306
Author(s):  
Jordan Ewing ◽  
Thomas Oommen ◽  
Paramsothy Jayakumar ◽  
Russell Alger
Keyword(s):  
Machine Learning ◽  
Remote Sensing ◽  
Learning Algorithms ◽  
Predictor Variable ◽  
Thermal Inertia ◽  
Soil Strength ◽  
In Situ Measurements ◽  
Machine Learning Algorithms ◽  
Soil Stiffness

Soil strength characterization is essential for any problem that deals with geomechanics, including terramechanics/terrain mobility. Presently, the primary method of collecting soil strength parameters through in situ measurements but sending a team of people out to a site to collect data this has significant cost implications and accessing the location with the necessary equipment can be difficult. Remote sensing provides an alternate approach to in situ measurements. In this lab study, we compare the use of Apparent Thermal Inertia (ATI) against a GeoGauge for the direct testing of soil stiffness. ATI correlates with stiffness, so it allows one to predict the soil strength remotely using machine-learning algorithms. The best performing regression algorithm among the ones tested with different predictor variable combinations was found to be KNN with an R2 of 0.824 and a RMSE of 0.141. This study demonstrates the potential for using remote sensing to acquire thermal images that characterize terrain strength for mobility utilizing different machine-learning algorithms.

Stacked pile solution for axial load–settlement analysis of driven piles in multi-layered soils

2020 ◽  
Vol 57 (6) ◽  
pp. 851-870
Author(s):  
Fawad S. Niazi ◽  
Karl E. Wangensten-Øye
Keyword(s):  
Back Analysis ◽  
Layered System ◽  
Deep Foundations ◽  
Layered Soils ◽  
Driven Piles ◽  
Soil Stiffness ◽  
Analysis Process ◽  
Pile Model ◽  
Modulus Reduction

The load–settlement (Q–s) response of deep foundations is influenced by the soil stiffness. One of the most common methods of installing these foundations is the process of driving, which changes the in situ soil stress and stiffness regime. The stiffness further reduces in a nonlinear manner as the loads and shearing strains increase within the soil. The decay in the stiffness of the soil surrounding an axially loaded pile varies with depth. While a variety of methods is available to predict the nonlinear Q–s response of piles in relatively simpler soil profiles, only select methods can handle the case of multi-layered soils, where the stiffness properties vary between layers. As an alternative, the Randolph analytical pile solution is exploited for (i) developing a new modulus reduction scheme from the back-analysis of load tests on driven piles that also accounts for plasticity of the soil, (ii) devising a methodology for generating modulus reduction curves for individual layers of a multi-layered system, and (iii) formulating a stacked pile model with integration of modulus reduction curves for an improved solution. The back-analysis process accounts for the installation effects on the in situ soil stiffness. A step-wise flowchart and example applications of the methodology are also presented.

scholarly journals Mesure du module en petites déformations d'un sol autour d'une conduite enterrée : présentation d'un nouvel essai in situ

2000 ◽  
Vol 37 (4) ◽  
pp. 909-917 ◽  
Author(s):  
Olivier Thépot ◽  
Roger Frank
Keyword(s):  
Test Procedure ◽  
Three Dimensional ◽  
Longitudinal Direction ◽  
Displacement Curve ◽  
Flexible Pipe ◽  
Soil Stiffness ◽  
Test Soil ◽  
Force Displacement ◽  
Small Deformations

A new method of measurement of backfill stiffness around buried flexible pipe is presented. It consists of using flexible pipe as an expanding pressiometric probe. The pipe dilatation is obtained by an internal jacking test that causes a relatively small three-dimensional "ovalization" around 0.05%. We obtain a force-displacement curve along the force axis as well as the damping of the displacement in the longitudinal direction up to one diameter in range. Knowing the pipe mechanical characteristics, we can calculate Young's modulus of the backfill in the domain of small deformations. The paper describes the test procedure as well as the modulus computation technique, which is based upon a three-dimensional parametric study using the finite element method. The results obtained in a jacking test conducted on iron pipe of 1.4 m in diameter and 8.0 m in length are presented. The computed moduli are compared with the ones obtained in laboratory testing using resonant-column and cyclic triaxial tests.Key words: buried pipes, jacking test, soil stiffness, soil-structure interaction, three-dimensional analysis, finite elements.

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