Behavior of an embankment on New York varved clay

1978 ◽  
Vol 15 (2) ◽  
pp. 250-268 ◽  
Author(s):  
Francis D. Leathers ◽  
Charles C. Ladd
Keyword(s):  
New York ◽  
Cross Sections ◽  
New York State ◽  
Three Dimensional ◽  
Field Measurements ◽  
Finite Element Program ◽  
Pore Pressures ◽  
Element Program ◽  
Prediction Techniques ◽  
Varved Clay

The foundation soils for an embankment in New York State constructed on preconsolidated varved clay were instrumented to determine pore pressures and settlements during and after construction. Four embankment cross sections, three of which had sand drains, are analyzed in this paper. Predictions of the in situ undrained pore pressures, initial settlements and final consolidation settlements are presented and compared with the results of field measurements. Undrained pore pressures and initial settlements are predicted using the finite element program FEECON for plane strain embankment conditions and elastic theory for three-dimensional embankment conditions. Final consolidation settlements are predicted using a modification of the Skempton–Bjerrum approach. At cross sections with sand drains, predicted undrained pore pressures are adjusted to account for the effect of the sand drains. In addition, vertical and horizontal coefficients of consolidation are determined from the field measurements and compared with laboratory values of vertical coefficients of consolidation. The results of the investigation indicate that the proposed prediction techniques yield reasonable predictions of undrained pore pressure and initial settlement. Additional case studies are required in order to evaluate the predictive methods for the rate and amount of consolidation settlement.

Undrained behavior of embankments on New Liskeard varved clay

1977 ◽  
Vol 14 (3) ◽  
pp. 367-388 ◽  
Author(s):  
Suzanne M. Lacasse ◽  
Charles C. Ladd ◽  
Alex K. Barsvary
Keyword(s):  
Finite Element ◽  
Effective Stress ◽  
Field Measurements ◽  
Excess Pore Pressure ◽  
Strength Parameters ◽  
Finite Element Program ◽  
Pore Pressures ◽  
Element Program ◽  
Varved Clay ◽  
Excess Pore

The performance, including a failure, of two embankments in New Liskeard, Ontario is analysed. The underlying medium-to-soft varved clay foundation is studied with respect to stability, undrained deformations, and excess pore pressure distribution.Total stress stability analyses were performed with undrained strengths based on measured and corrected field vane strengths, the average unconfined compression and unconsolidated undrained strength, and SHANSEP strength parameters with and without anisotropy. Several approaches yielded satisfactory factors of safety and reasonable critical arcs. Effective stress analyses using pore pressures predicted from finite element analyses showed that either the effective stress strength parameters were much lower than those measured in the laboratory or the predicted pore pressures at failure were much too low.Undrained deformations and excess pore pressures at end-of-construction were predicted with the finite element program FEECON. The values were generally consistent with field measurements for an embankment located 60 m from the failure area.

Application of a multilaminate model to simulate the undrained response of structured clay to shield tunnelling

2008 ◽  
Vol 45 (1) ◽  
pp. 14-28 ◽  
Author(s):  
H. Kien Dang ◽  
Mohamed A. Meguid
Keyword(s):  
Field Measurements ◽  
Soil Parameters ◽  
Explicit Integration ◽  
Integration Algorithm ◽  
Finite Element Program ◽  
Surface Displacements ◽  
Implicit Integration Algorithm ◽  
Element Program ◽  
Shield Tunnelling ◽  
Structured Clay

A constitutive model based on the multilaminate framework has been implemented into a finite element program to investigate the effect of soil structure on the ground response to tunnelling. The model takes into account the elastic unloading–reloading, inherent and induced anisotropy, destructuration, and bonding effects. The model is successfully calibrated and used to investigate the undrained response of structured sensitive clay in the construction of the Gatineau tunnel in Gatineau, Quebec. Numerical results were compared to the field measurements taken during tunnel construction. To improve the performance of the numerical model, an implicit integration algorithm is implemented and proven to be very effective when coupled with the multilaminate framework as compared to the conventional explicit integration methods. The effect of different soil parameters including bonding and anisotropy on the tunnelling induced displacements and lining stresses is also examined using a comprehensive parametric study. The results indicated that soil bonding and anisotropy have significant effects on the shape of the settlement trough as well as the magnitudes of surface displacements and lining stresses induced by tunnelling.

scholarly journals Analysis of high-rise constructions with the using of three-dimensional models of rods in the finite element program PRINS

2018 ◽  
Vol 33 ◽  
pp. 02033
Author(s):  
Vladimir Agapov
Keyword(s):  
Rectangular Cross Section ◽  
Three Dimensional ◽  
Free Vibrations ◽  
Finite Element Program ◽  
One Dimensional ◽  
Static And Dynamic Analysis ◽  
High Rise ◽  
Element Program ◽  
Dimensional Models ◽  
Three Dimensional Models

The necessity of new approaches to the modeling of rods in the analysis of high-rise constructions is justified. The possibility of the application of the three-dimensional superelements of rods with rectangular cross section for the static and dynamic calculation of the bar and combined structures is considered. The results of the eighteen-story spatial frame free vibrations analysis using both one-dimensional and three-dimensional models of rods are presented. A comparative analysis of the obtained results is carried out and the conclusions on the possibility of three-dimensional superelements application in static and dynamic analysis of high-rise constructions are given on its basis.

3D Numerical Modelling of the Wave-Induced Response Around the Circular Caisson Founded on the Seabed

2008 ◽  
Author(s):  
Andrew H. C. Chan ◽  
Jian-Hua Ou
Keyword(s):  
Three Dimensional ◽  
Dynamic Interaction ◽  
Induced Response ◽  
Marine Structures ◽  
Finite Element Program ◽  
3D Numerical Modelling ◽  
Element Program ◽  
Main Factors ◽  
The Stability ◽  
Wave Induced

Wave-induced liquefaction is one of the main factors influence the stability of marine structures. However, the investigation on this phenomenon is complicated as the dynamic interaction between soil, pore fluid and the structure is closely coupled. In order to obtain a better understanding of the wave-induced response around the circular caisson founded in the seabed, three dimensional numerical analyses have been performed using the 3D finite element program DYNE3WAC in order to investigate the wave-induced response around the circular caisson.

Comparative Analysis of Several Construction Scheme of a Large-Sized Tie-Arch Aqueduct

2011 ◽  
Vol 94-96 ◽  
pp. 2350-2354
Author(s):  
Shu Zhong Lei ◽  
Zhong Xin Wang ◽  
Jian Ting Xu ◽  
Chi Peng Liu
Keyword(s):  
Comparative Analysis ◽  
Prestressed Concrete ◽  
Three Dimensional ◽  
Stability Control ◽  
River Diversion ◽  
Finite Element Program ◽  
Dimensional Finite Element ◽  
Element Program ◽  
Stress And Deformation ◽  
Three Dimensional Finite Element

An aqueduct of larger-span prestressed concrete arch structure for river diversion project is located in coastal areas, and raises difficult questions on deformation and stability control of the construction process due to greater wind load and poor soil. Due to the limited width of bracket erection, this paper put forward five possible construction schemes, and does the comparative analysis using three-dimensional finite element program, and gets the economic and reasonable one. Finally conduct a pressure test after the bracket erection, and verify the analysis results using measured stress and deformation data.

Static and Dynamic Analyses of the LSES Hull Structure

1978 ◽  
Vol 22 (02) ◽  
pp. 110-122
Author(s):  
A. S. Hananel ◽  
E. J. Dent ◽  
E. J. Philips ◽  
S. H. Chang
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Surface Effect ◽  
Three Dimensional ◽  
Element Model ◽  
Finite Element Program ◽  
Hull Structure ◽  
Surface Effect Ship ◽  
Hull Design ◽  
Element Program

To avoid the conservativeness in the large surface-effect ship hull design which results from simplifying assumptions in the stress analysis, the hull structure was analyzed as a three-dimensional elastic body. The NASTRAN finite-element program, level 15.0, was selected for use in this analysis as the most suitable program available. A finite-element model representing the true hull stiffness was used in obtaining the internal load and displacement distributions. The inertia effect of the ship masses was included with each set of static loads. This was done by using the Static Analysis with Inertia Relief solution included in NASTRAN. The stress redistribution around cutouts in the hull was treated in a separate study. The interaction between hull and deckhouse was investigated by attaching a model of the deckhouse onto the hull model, and then solving for the appropriate load conditions. The natural frequencies were obtained using a reduced finite-element model of both the hull and hull/deckhouse combination. A new technique was developed for determining the dynamic stresses and their proper superposition on the static stresses.

scholarly journals Quantification of Extent, Density, and Status of Aquatic Reed Beds Using Point Clouds Derived from UAV–RGB Imagery

2018 ◽  
Vol 10 (12) ◽  
pp. 1869 ◽  
Author(s):  
Nicolás Corti Meneses ◽  
Florian Brunner ◽  
Simon Baier ◽  
Juergen Geist ◽  
Thomas Schneider
Keyword(s):  
Cross Sections ◽  
Vegetation Index ◽  
Low Cost ◽  
Three Dimensional ◽  
Field Measurements ◽  
Point Clouds ◽  
Conservation Strategies ◽  
Reed Beds ◽  
Combining Data ◽  
Reed Bed

Quantification of reed coverage and vegetation status is fundamental for monitoring and developing lake conservation strategies. The applicability of Unmanned Aerial Vehicles (UAV) three-dimensional data (point clouds) for status evaluation was investigated. This study focused on mapping extent, density, and vegetation status of aquatic reed beds. Point clouds were calculated with Structure from Motion (SfM) algorithms in aerial imagery recorded with Rotary Wing (RW) and Fixed Wing (FW) UAV. Extent was quantified by measuring the surface between frontline and shoreline. Density classification was based on point geometry (height and height variance) in point clouds. Spectral information per point was used for calculating a vegetation index and was used as indicator for vegetation vitality. Status was achieved by combining data on density, vitality, and frontline shape outputs. Field observations in areas of interest (AOI) and optical imagery were used for reference and validation purposes. A root mean square error (RMSE) of 1.58 m to 3.62 m for cross sections from field measurements and classification was achieved for extent map. The overall accuracy (OA) acquired for density classification was 88.6% (Kappa = 0.8). The OA for status classification of 83.3% (Kappa = 0.7) was reached by comparison with field measurements complemented by secondary Red, Green, Blue (RGB) data visual assessments. The research shows that complex transitional zones (water–vegetation–land) can be assessed and support the suitability of the applied method providing new strategies for monitoring aquatic reed bed using low-cost UAV imagery.

The strain hardening behaviour of particulate media

1976 ◽  
Vol 13 (3) ◽  
pp. 311-323 ◽  
Author(s):  
S. Frydman
Keyword(s):  
Strain Hardening ◽  
Three Dimensional ◽  
Flow Rule ◽  
Finite Element Program ◽  
Particulate Media ◽  
Stress Strain Relation ◽  
Element Program ◽  
Plastic Components ◽  
Associated Flow Rule ◽  
Particulate Medium

The strain increment resulting from an increment of stress applied to a particulate medium has been expressed in terms of its elastic and plastic components. The concepts of strain-hardening plasticity have been employed to develop an incremental stress–strain relation, based on a non-associated flow rule. The parameters appearing in the relation have been found using results of three-dimensional shear tests on sands and glass-microspheres. It is suggested that relations of the type developed in the paper could be beneficially incorporated into a finite-element program.

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