An integrated geotechnical–geophysical investigation of soft clay at a coastal site in the Mekong Delta for oil and gas infrastructure development

2008 ◽  
Vol 45 (11) ◽  
pp. 1514-1524 ◽  
Author(s):  
Pham Huy Giao ◽  
N. T. Dung ◽  
P. V. Long
Keyword(s):  
Oil And Gas ◽  
Soft Clay ◽  
Mekong Delta ◽  
Site Investigation ◽  
Soil Parameters ◽  
Infrastructure Development ◽  
Geophysical Investigation ◽  
Soft Clays ◽  
Clay Deposit ◽  
Geophysical Study

An adequate site investigation of soft clays is important for construction of oil and gas facilities on coastal areas in the Mekong Delta. This paper presents an integrated geotechnical–geophysical study of the soft clay deposit at the Ca Mau site, located on the west coast of southern Vietnam. The geotechnical data were analyzed to provide a detailed characterization of the subsoil profile and soil parameters that can be used in the design works. It is also the first time the electric imaging procedure has been successfully applied in the Mekong Delta to assist the local geotechnical engineers in site investigation of a very soft clay deposit.

Deformability and consolidation characteristics of soft Bangkok clay using screw plate tests

1990 ◽  
Vol 27 (5) ◽  
pp. 531-545 ◽  
Author(s):  
D. T. Bergado ◽  
K. C. Chong ◽  
P. A. M. Daria ◽  
M. C. Alfaro
Keyword(s):  
Graphical Method ◽  
Soft Clay ◽  
Stress Path ◽  
Soil Parameters ◽  
Test Results ◽  
Coefficient Of Consolidation ◽  
Plate Test ◽  
Settlement Time ◽  
Oedometer Tests ◽  
Test Embankment

This study centred on the performance of the screw plate test (SPLT) to determine the deformability and consolidation characteristics of soft Bangkok clay. For comparison, a series of stress-path-controlled triaxial consolidation tests (tri) were carried out on good quality samples of Bangkok clay taken from the same testing sites and imposed with the same loading conditions as the screw plate tests. Undrained and drained moduli and coefficients of consolidation were obtained from the stress-path-controlled triaxial consolidation tests and were compared with the corresponding values of the screw plate test. In addition, the ultimate bearing capacity was derived from the pressure–deformation relationships of the screw plate test results. A graphical method was used to compute the coefficient of consolidation from the screw plate tests and from stress-path-controlled triaxial consolidation test results. The compressibility data were also obtained from conventional oedometer tests (oed). Both cv (SPLT)/cv (tri) and cv (SPLT)/cv(oed) ratios compared favorably with the cv (field)/cv (laboratory) ratio obtained from past investigations. The data from pressure–settlement–time relationships of the screw plate tests were used to successfully predict values that compared favorably with the measured values at each stress level. The pressure–deformation–time relationship from stress-path-controlled triaxial consolidation tests were also evaluated, and they indicated behaviour similar to that of the screw plate test results. Soil parameters obtained from screw plate tests were subsequently used to predict the settlement of two test embankments, giving fairly close agreement with the observed values. Key words: soft clay, settlement, deformation, consolidation, screw plate test, triaxial test, embankment, prediction, stress path.

scholarly journals Assessing the undrained strength of very soft clays in the SPT

2021 ◽  
Vol 44 (4) ◽  
pp. 1-6
Author(s):  
Francisco Lopes ◽  
Osvangivaldo Oliveira ◽  
Marcio Almeida
Keyword(s):  
Standard Procedure ◽  
Soft Clay ◽  
Test Procedure ◽  
State Theory ◽  
Technical Note ◽  
Construction Site ◽  
Soft Clays ◽  
Design Engineers ◽  
Present Information ◽  
Undrained Strength

The log of a SPT in very soft clay may simply indicate a zero blow-count, or present information on the penetration – under self-weight – of the composition (sampler, rods and hammer) as recommended by some standards. The second type of information is often disregarded by design engineers due to the lack of a standard procedure for measuring these penetrations or because the test is regarded as not sensitive enough to give an indication on the undrained shear strength of soft clays. The penetration under the composition’s selfweight, however, can indicate the magnitude of Su, which, along with other more specific and sensitive tests, can help in assessing the spatial distribution of clay consistency in a large deposit. A proposed test procedure and interpretation had been given in an earlier technical note. This note presents an extended formulation and an evaluation of Su via the SPT at a construction site in Rio de Janeiro, including comparisons with results of piezocone and vane tests. The values of Su obtained with the SPT lie between the profiles given by vane tests, corrected by Plasticity Index, and the Critical State Theory, the latter representing a lower bound to the clay strength.

scholarly journals Justification of integrated environmental and economic assessment of the impact actions in the field of oil and gas extraction

2017 ◽  
Vol 8 (4) ◽  
pp. 25-30
Author(s):  
Oleksandr Matsenko ◽  
Olga Gramma
Keyword(s):  
Energy Security ◽  
Power Plants ◽  
Oil And Gas ◽  
Economic Assessment ◽  
Well Being ◽  
Petroleum Products ◽  
Primary Energy ◽  
Infrastructure Development ◽  
Military Operations ◽  
The Impact

The aim of the welfare state, in accordance with the Constitution of Ukraine is to ensure conditions for the growth of welfare of citizens. One of the major components in the well-being of civilized societies is to ensure that citizens and businesses the necessary energy. Energy development is the basis for enhancing the social and economic living standards of the population and competitiveness. The key to this goal should be a reliable, economically viable and environmentally sound needs of the population and the economy of energy products. It is important to identify the critical factors is a threat to the energy security of the national economy. The state of the energy sector of Ukraine is negatively affected by continued dependence on imports of Russian natural gas, petroleum products and fuel for power plants. Today such dependence on primary energy, including coal, has become a leverage to Ukraine on the part of the neighboring state. The loss of the fuel and energy complex, and areas for future development of hydrocarbon resources as a result of the annexation of the Crimea and the military operations in the east of the country, as well as the destruction of the oil and gas infrastructure in the Donetsk and Luhansk regions, yielded additional new factors which significantly weakened the energy security of the country. Given the instability of strategic task for Ukraine, it is vital to achieve the highest possible level to ensure the economy’s own oil and gas resources, which, to a certain extent, will contribute to energy independence and savings of foreign exchange reserves of the country, as well as infrastructure development in the industry, tax revenues, creation of additional jobs.

scholarly journals Participatory Mapping for Strengthening Environmental Governance on Socio-Ecological Impacts of Infrastructure in the Amazon: Lessons to Improve Tools and Strategies

2021 ◽  
Vol 13 (24) ◽  
pp. 14048
Author(s):  
Carla Mere-Roncal ◽  
Gabriel Cardoso Carrero ◽  
Andrea Birgit Chavez ◽  
Angelica Maria Almeyda Zambrano ◽  
Bette Loiselle ◽  
...  
Keyword(s):  
Large Scale ◽  
Environmental Governance ◽  
Oil And Gas ◽  
Good Governance ◽  
Knowledge Exchange ◽  
Ecological Impacts ◽  
Participatory Mapping ◽  
Infrastructure Development ◽  
Development Agenda ◽  
Novel Approach

The Amazon region has been viewed as a source of economic growth based on extractive industry and large-scale infrastructure development endeavors, such as roads, dams, oil and gas pipelines and mining. International and national policies advocating for the development of the Amazon often conflict with the environmental sector tasked with conserving its unique ecosystems and peoples through a sustainable development agenda. New practices of environmental governance can help mitigate adverse socio-economic and ecological effects. For example, forming a “community of practice and learning” (CoP-L) is an approach for improving governance via collaboration and knowledge exchange. The Governance and Infrastructure in the Amazon (GIA) project, in which this study is embedded, has proposed that fostering a CoP-L on tools and strategies to improve infrastructure governance can serve as a mechanism to promote learning and action on factors related to governance effectiveness. A particular tool used by the GIA project for generating and sharing knowledge has been participatory mapping (Pmap). This study analyzes Pmap exercises conducted through workshops in four different Amazonian regions. The goal of Pmap was to capture different perspectives from stakeholders based on their experiences and interests to visualize and reflect on (1) areas of value, (2) areas of concern and (3) recommended actions related to reducing impacts of infrastructure development and improvement of governance processes. We used a mixed-methods approach to explore textual analysis, regional multi-iteration discussion with stakeholders, participatory mapping and integration with ancillary geospatial datasets. We believe that by sharing local-knowledge-driven data and strengthening multi-actor dialogue and collaboration, this novel approach can improve day to day practices of CoP-L members and, therefore, the transparency of infrastructure planning and good governance.

Behaviour of friction piles in soft sensitive clays

1980 ◽  
Vol 17 (2) ◽  
pp. 203-224 ◽  
Author(s):  
R. Blanchet ◽  
F. Tavenas ◽  
R. Garneau
Keyword(s):  
Precast Concrete ◽  
Soft Clay ◽  
Load Test ◽  
Pile Groups ◽  
Test Program ◽  
Shear Creep ◽  
Soft Clays ◽  
The North ◽  
Effective Stress Analysis

During the construction of heavy structures, such as bridges and overpasses, on soft clays on the north shore of the St. Lawrence Valley, a detailed load test program on friction piles was performed to establish the characteristics of the most suitable type of pile and to study its long-term behaviour. Three types of piles, timber, steel pipe with closed end, and precast concrete Herkules H-420 piles, were tested. Four timber piles driven in a group and submitted to a 712 kN load served to study the long-term settlement of a small group of piles. Three deep settlement gauges were installed in the centre of this group for measuring settlements in clay at various depths.This test program was completed by the instrumentation of two bridge piers in order to verify the behaviour of larger groups of piles.The paper presents the results of the test piles, the long-term behaviour (4 years) of the bridge pier foundations resting on friction piles in soft clay, and the interpretation of the results.This study shows that the pore pressures induced by pile driving are related to the pre-consolidation of the clay and that they are much larger for tapered piles. It is demonstrated that the effective stress analysis method proposed in 1976 by Meyerhof determines adequately the ultimate pile bearing capacity, but that the effect of the timber pile taper doubles the skin friction.The settlement analysis of pile groups shows that settlements are due to the reconsolidation of the clay and shear creep deformations in the clay close to the pile wall.

Experience with Interface Shear Box Testing for Pipe-Soil Interaction Assessment on Sand

2021 ◽  
Author(s):  
Zack Westgate ◽  
Ricardo Argiolas ◽  
Regis Wallerand ◽  
Jean-Christophe Ballard
Keyword(s):  
Soil Properties ◽  
Normal Stress ◽  
Oil And Gas ◽  
Early Stage ◽  
Soft Clay ◽  
Interface Roughness ◽  
Coarse Grained ◽  
Interface Shear ◽  
Shear Box ◽  
Test Database

Abstract This paper is a companion paper to OTC 28671, titled "Experience with Interface Shear Box Testing for Axial Pipe-Soil Interaction Assessment on Soft Clay", and presents a similar range of experience and best practice recommendations for geotechnical laboratory testing to determine soil properties relevant to pipeline-seabed friction on sandy seabeds. The paper is underpinned by a new database that demonstrates the driving parameters that influence interface friction in granular materials. By accurately quantifying shear resistance along the pipe-soil interface under low normal stresses imposed by subsea pipelines, design ranges in friction can be narrowed and/or tailored to specific pipeline conditions. These improved geotechnical inputs to pipe-soil interaction can alleviate unnecessary axial expansion mitigation and lateral stabilization measures, unlocking cost savings otherwise unavailable through conventional testing. A large database is presented, compiled from both previously published research and unpublished recent industry experience with low normal stress interface shear testing using various modified direct shear box devices. The test database comprises several coarse-grained soil types of both silica and carbonate minerology tested against pipeline coatings of various material, hardness and roughness. The database populates a framework for assessing frictional pipe-soil interaction response, illuminating key trends from normal stress, interface roughness and hardness, and particle angularity, which otherwise remain elusive when examined through individual test datasets. This database and the populated framework provides guidance to pipeline and geotechnical engineers in the form of a basis for initial estimates of axial and lateral friction of pipelines on sand and an approach for improving these estimates via focused site-specific testing. The test database includes previously unreleased project data collected over the past few years for offshore oil and gas projects. Similar to its predecessor paper on soft clays (OTC 28671), this paper shares the authors’ collective experience providing guidance on the planning, execution and interpretation of low stress interface shear tests in sands. The combined databases across both papers provide a significant improvement in early stage guidance for characterization of geotechnical soil properties for subsea pipeline design.

scholarly journals Laboratory development of a vertically oriented penetrometer for shallow seabed characterization

2016 ◽  
Vol 53 (1) ◽  
pp. 93-102 ◽  
Author(s):  
Fauzan Sahdi ◽  
David J. White ◽  
Christophe Gaudin ◽  
Mark F. Randolph ◽  
Noel Boylan
Keyword(s):  
Soil Surface ◽  
Site Investigation ◽  
Soil Strength ◽  
Small Scale ◽  
Soil Parameters ◽  
Embedment Depth ◽  
Fine Grained ◽  
Centrifuge Models ◽  
Measured Resistance ◽  
And Performance

Current site investigation practice for offshore pipeline design relies on soil parameters gathered from boreholes or in situ test soundings to depths of 1–2 m below the mudline. At these depths, the fine-grained seabed is very soft and possesses low undrained strength, which can be difficult to measure. This paper describes a centrifuge test programme undertaken to evaluate the feasibility and performance of a novel penetrometer designed to assess the shallow strength of soft seabed over continuous horizontal profiles. This device is termed the vertically oriented penetrometer (VOP). Tests were performed on a normally consolidated kaolin sample, with the VOP translated horizontally at velocities ranging from 1 to 30 mm/s, after embedding the VOP at 30 and 45 mm depths. All tests involved many cycles of VOP forward and backward movement to assess its potential to derive the ratio of intact to fully remoulded strength. Strength determination is achieved by dragging the VOP at a specified embedment depth along the soil surface, and deriving the soil strength from the measured resistance as if the VOP were a laterally loaded pile. The VOP is shown to yield comparable strength measurements to that of a T-bar penetrometer. The VOP is a potentially valuable addition to the range of tools used to characterize soil strength, both in small-scale centrifuge models and, following practical development, potentially also in the field.

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