A geotechnical investigation of marine deposits in a nearshore seabed for land reclamation

1999 ◽  
Vol 36 (6) ◽  
pp. 981-1000 ◽  
Author(s):  
Kin-Man Lee ◽  
Patrick CC Ng
Keyword(s):  
Land Reclamation ◽  
Large Diameter ◽  
Field Tests ◽  
In Situ Tests ◽  
Coefficient Of Consolidation ◽  
Marine Deposits ◽  
Undisturbed Samples ◽  
Horizontal Drainage ◽  
Rowe Cell

The properties of marine deposits in a nearshore seabed at a land reclamation site in Hong Kong were investigated. A variety of laboratory and in situ tests were conducted to define the geotechnical and consolidation characteristics of the marine deposits. The reliability and applicability of various laboratory and in situ testing techniques in evaluating the coefficient of consolidation were examined. Coefficients of consolidation were calculated from conventional oedometer tests, large-diameter (250 mm) Rowe cell tests, field permeability tests, and piezocone dissipation tests. Three techniques were adopted to evaluate the horizontal coefficient of consolidation ch from the results of in situ piezocone dissipation tests. Results from in situ pore pressure dissipation tests are compared with those from large-diameter Rowe cell tests performed on undisturbed samples under both vertical and horizontal drainage conditions and in situ permeability tests to provide reference values of the vertical coefficient of consolidation cv and ch. The engineering implications, particularly those related to land reclamation work in the nearshore environment, of various laboratory and field tests are discussed.

In situ estimation of the coefficient of consolidation in clays

1990 ◽  
Vol 27 (1) ◽  
pp. 58-67 ◽  
Author(s):  
Mohammed G. Kabir ◽  
Alan J. Lutenegger
Keyword(s):  
Key Words ◽  
Pore Pressure ◽  
Reference Values ◽  
Time Factors ◽  
In Situ Tests ◽  
Coefficient Of Consolidation ◽  
Oedometer Test ◽  
Undisturbed Samples ◽  
Oedometer Tests

An investigation was conducted to demonstrate the applicability of cylindrical piezocone and flat piezoblade tests for providing reliable estimates of the coefficient of consolidation in clays. Coefficients of consolidation were calculated from piezocone dissipation tests for different degrees of consolidation using theoretical time factors to provide a comparison with laboratory oedometer tests. Three techniques were developed to calculate the coefficient of consolidation from piezoblade dissipation tests. Results from in situ pore pressure dissipation tests were compared with laboratory oedometer tests performed on undisturbed samples oriented in both the vertical and horizontal directions, to provide reference values of cv and ch. The results of investigations conducted at several clay sites are presented. Key words: in situ tests, piezocone, piezoblade, coefficient of consolidation, oedometer test, clays.

Back-calculation of consolidation parameters from field measurements at a reclamation site

2001 ◽  
Vol 38 (4) ◽  
pp. 755-769 ◽  
Author(s):  
Lai Fa Cao ◽  
Ming-Fang Chang ◽  
Cee Ing Teh ◽  
Yung Mook Na
Keyword(s):  
Pore Pressure ◽  
Land Reclamation ◽  
Ground Improvement ◽  
Field Measurements ◽  
Coefficient Of Consolidation ◽  
Vertical Drains ◽  
Undisturbed Samples ◽  
Back Calculation ◽  
Reclamation Project ◽  
Consolidation Parameters

A pilot test was carried out at a land reclamation project site to study the effect of vertical drains on the rate of consolidation of a marine clay deposit in Singapore. Theoretical and numerical analyses were conducted to interpret the field measurements of pore pressure and settlement, and consolidation parameters were back-calculated. The back-calculated preconsolidation pressure is similar to that obtained from the laboratory consolidation test on undisturbed samples, but the field-deduced compression index is generally larger than that measured in the laboratory. The coefficient of consolidation back-calculated from the settlement measurement is larger than that from the pore-pressure measurement. The coefficient of consolidation for horizontal flow obtained from the Rowe cell test, which is comparable to that back-calculated from the field settlement measurement, is recommended for the preliminary design of vertical drains without the need of considering the smear effect.Key words: clays, consolidation, ground improvement, numerical modelling and analysis, permeability, vertical drains.

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 Evaluation of Stiffness Degradation Curves from in Situ Tests in Various Soil Types

2018 ◽  
Vol 64 (4) ◽  
pp. 285-307
Author(s):  
T. Godlewski
Keyword(s):  
Field Tests ◽  
Shear Stiffness ◽  
Test Methods ◽  
Soil Types ◽  
Design Parameters ◽  
Design Calculation ◽  
In Situ Tests ◽  
Nonlinearity Test ◽  
Strain Dependent

AbstractIncreasingly complex design systems require an individual approach when determining the necessary design parameters. As soils are characterized by strong strain-dependent nonlinearity, test methods used to characterize the subsoil should be carefully selected, in terms of their “sensitivity” as well as suitability for the analyzed type of problem. When direct measurements are not available, while design calculation models require specific parameters, indirect parameter estimation may be used. This approach requires calibration and validation of empirical correlations, based on well documented database of tests and case studies. One of the parameters often used, when analyzing soil-structure interaction problems, is the shear stiffness of the soil and its strain-dependent degradation. The aim of the article is to present the procedure for description and evaluation of soil stiffness based on field tests (CPTU, DMT and SDMT) and a large number of reference curves obtained from laboratory tests (TRX) for selected soil types. On the basis of the given algorithm, it is possible to obtain a stiffness module G0 value at any level of deformation, based on in-situ tests.

scholarly journals In Situ Lateral Load Tests on Instrumented Bored Piles in Loessial Soils

2017 ◽  
Vol 13 (1) ◽  
pp. 1-11
Author(s):  
Sebastian Drăghici ◽  
Anatolie Marcu
Keyword(s):  
Large Diameter ◽  
In Situ Tests ◽  
Laterally Loaded Piles ◽  
Natural Moisture Content ◽  
Load Tests ◽  
Bored Piles ◽  
Strength And Stiffness ◽  
Laterally Loaded ◽  
Plaxis 3D

Abstract The aim of the paper is to provide some aspects regarding the behaviour of laterally loaded piles in loessial soils, by presenting and analysing the results of several in situ tests on large diameter bored piles in this type of soil. The major feature of loess is that it exhibits a massive decline of its strength and stiffness parameters when it comes into contact with water, leading to the collapse of its structure even under self-weight and creating difficult conditions for foundations. The load tests were performed both in natural moisture content loess and also in saturated loess. The results obtained by means of instrumentation are back-analysed using current analytical methods and also by finite element method using a numerical model in the geotechnical computation software Plaxis 3D.

scholarly journals Field Test and Numerical Simulation for Coordinated Deformation of New Subgrade and Old Embankment Adjacent to River

2018 ◽  
Vol 8 (12) ◽  
pp. 2334 ◽  
Author(s):  
Jihong Wei ◽  
Zezhuo Song ◽  
Yuxia Bai ◽  
Jin Liu ◽  
Debi Kanungo ◽  
...  
Keyword(s):  
Numerical Modeling ◽  
Research Work ◽  
Drainage System ◽  
Field Tests ◽  
Creep Model ◽  
Soft Ground ◽  
Band Model ◽  
In Situ Tests ◽  
Wall Model

With the development of the economy in China, original roads may be unable to cope with the existing traffic. The expansion of the old embankment is the core problem for road expansion. Soft foundation differential settlements and pavement cracking along the joint between the new subgrade and old embankment often emerge after construction, especially during the operational period of the road. The Binjiang Avenue Project in Nanjing, China, is taken as a research example in this paper, and a typical test zone of about 300.0 m in length was selected to conduct research work through in-situ tests. The coordinated deformations of the subgrade combined with the old embankment under conditions of consolidation by drainage were researched using in-situ tests and numerical modeling. During the process of numerical modeling, the vertical drainage system in the compressible soft ground layers was simplified to be represented as the drainage band model and the equivalent sand-wall model. In addition, a soft ground creep model was adopted to calculate the deformation of the subgrade with the construction process. A comparison of the results between field tests and numerical simulations was carried out. The results show that there is good uniformity for both. Based on the results, three indexes for the new and old subgrade, such as the differential settlement, total settlement and post-settlement, should be viewed as the basis for the design and construction of the new subgrade and old embankment. Additionally, it was found that the soft ground model, drainage band model and equivalent sand-wall model are all completely suitable for the numerical modeling of the soft ground reinforcement subgrade. These results also provide a theoretical basis for the construction method of similar projects.

Deep-seated consolidation settlements in the Fraser River delta

1991 ◽  
Vol 28 (2) ◽  
pp. 298-303 ◽  
Author(s):  
C. B. Crawford ◽  
N. R. McCammon ◽  
R. C. Butler
Keyword(s):  
River Delta ◽  
Fraser River ◽  
In Situ Tests ◽  
Case Record ◽  
The Past ◽  
Undisturbed Samples ◽  
Consolidation Settlement ◽  
Fraser River Delta ◽  
Heavy Loads

This paper describes the settlements of three heavy silo structures at two cement plants located along the south arm of the Fraser River delta. In this area, it has not been possible to obtain sufficiently undisturbed samples for reliable consolidation tests, and it has been necessary therefore to employ in situ tests and site improvement techniques such as preloading and vibrocompaction for the design of foundations. In some cases, piles were used to redistribute heavy loads. Observations during the past 35 years have shown that most of the consolidation settlement has occurred in a deep layer of marine sediments and that it is largely completed within 10 years of the loading. Key words: case record, consolidation, foundation performance, in situ tests, preloading, settlements, site improvement.

Developments for in Situ Tests on Compacted Bentonite-Based Buffer Material

1990 ◽  
Vol 212 ◽  
Author(s):  
B. H. Kjartanson ◽  
M. N. Gray ◽  
B.C.M. Pulles
Keyword(s):  
Large Scale ◽  
Large Diameter ◽  
Full Scale ◽  
In Situ Tests ◽  
Buffer Material ◽  
In Situ Experiments ◽  
Buffer Mixture ◽  
Underground Research Laboratory ◽  
Nuclear Fuel Waste

ABSTRACTAECL Research is carrying out large-scale in situ experiments at its Underground Research Laboratory (URL). The Buffer/Container Experiment is designed principally to investigate the full scale, in situ performance of bentonite-based buffer material in a single emplacement borehole environment. In addition, the response of the rock to excavation and heating will be investigated. The experiment also allows for the development of the technologies needed to demonstrate some of the vault engineering activities proposed in the Canadian nuclear fuel waste disposal concept. These include excavation of large diameter boreholes for waste emplacement and in situ compaction of a bentonite/sand buffer mixture. Although these methodologies developed for the URL have not been optimized for the commercial, full-scale operations needed for a disposal vault, results show that the equipment and methodologies needed for vault operations are a reasonable extrapolation of existing technology.

scholarly journals Superdeep Tests and Experiments at 9.1 km and 4 km

2016 ◽  
Vol 2 ◽  
Author(s):  
Ulrich Harms ◽  
Jochem Kück
Keyword(s):  
Large Diameter ◽  
Crystalline Basement ◽  
Deep Drilling ◽  
In Situ Tests ◽  
Scientific Drilling ◽  
Basement Rocks ◽  
The Town ◽  
Continental Deep Drilling ◽  
Drilling Project

The Continental Deep Drilling Program of Germany (in German: Kontinentales Tiefbohrprogramm der Bundesrepublik Deutschland, abbreviated as KTB) was a scientific drilling project near the town of Windischeschenbach, Bavaria. The KTB Depth Laboratory comprises two 9.1 km and 4 km deep, water-filled boreholes in crystalline basement rocks just 200 meters apart from each other. Available equipment such as cables, winches, geophysical borehole tools as well as workshops and office infrastructure allows for in-situ tests and experiments at different pressure and temperature conditions. The two stable wells are large-diameter steel-cased and have been geophysically monitored in detail since 1996.

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