A coupled analysis of cavity and pore volume changes for pulse tests conducted in soft clay deposits

2013 ◽  
Vol 38 (9) ◽  
pp. 903-924 ◽  
Author(s):  
François Duhaime ◽  
Robert P. Chapuis
Keyword(s):  
Pore Volume ◽  
Soft Clay ◽  
Coupled Analysis ◽  
Volume Changes ◽  
Clay Deposits

scholarly journals Investigation of the Porosity of Certain Iraqi Clay Deposits by Mercury Porosimeter

2009 ◽  
Vol 6 (1) ◽  
pp. 163-172
Author(s):  
Baghdad Science Journal
Keyword(s):  
Pore Volume ◽  
Pore Diameter ◽  
Mercury Intrusion Porosimetry ◽  
Narrow Range ◽  
Volume Distribution ◽  
Natural Clay ◽  
Mercury Intrusion ◽  
Clay Deposits ◽  
Pore Area ◽  
Mercury Porosimeter

Pore volume, pore diameter, and pore volume distribution of three of Iraqi natural clay deposites were measured using mercury intrusion porosimetry .The clays are white kaolin, colored kaolin, and bentonite .The results showed that the variation of the pore area of the clay deposites followed the following order :- Coloured Kaolin > White Kaolin > Bentonite While the pore volume may be arranged as in the following sequence:- White Kaolin > Coloured Kaolin >Bentonite Also , Bentonite exhibits the narrow range pore size distribution than the white and coloured kaolin.

Ormen Lange Gas Field, Immediate Settlement of Offshore Rock Supports

2007 ◽  
Author(s):  
Guus de Vries ◽  
Joop van der Meer ◽  
Harald Brennodden ◽  
Stein Wendel
Keyword(s):  
Continental Shelf ◽  
Soft Clay ◽  
Back Analysis ◽  
Processing Plant ◽  
Gas Field ◽  
Clay Deposits ◽  
Calculation Results ◽  
The Uk ◽  
Rock Supports ◽  
Norwegian Continental Shelf

Located approximately 120 km offshore, Ormen Lange, with an estimated 400 billion m3 of natural gas, is the second-largest gas discovery on the Norwegian shelf. The water depth is up to 850 meters, making Ormen Lange the first deepwater project on the Norwegian Continental Shelf. The development of Ormen Lange is under shared operatorship between Norsk Hydro and Shell. Ormen Lange’s untreated well stream will be transported to shore in two 120 km long, 30-inch diameter pipelines to a processing plant at Nyhamna, Norway. From there, gas will be exported via a 42” 1200 km sub sea pipeline (Langeled) to Easington at the east coast of the UK. The pipelines have to pass over the Storegga slide edge which rises 200–300 meters toward the continental shelf in very steep slopes, which are also encountered in the nearshore Bjo¨rnsundet area. The uneven and steep seabed conditions require the use of approximately 2.8 million tons of rock to support and stabilize the pipelines. The sea bottom conditions on the Norwegian continental shelf are characterized by many outcrops as well as very soft clay deposits. The immediate settlement of the rock supports during installation form a significant amount of the total required rock volume. In this paper a procedure is presented on how to assess these immediate settlements recognizing four contributing components all being discussed separately. The calculation results are compared to a back-analysis, performed during the execution of the Ormen Lange rockworks, proving the suitability of the calculation method.

scholarly journals Prediction of spudcan penetration resistance profile in stiff-over-soft clays

2016 ◽  
Vol 53 (12) ◽  
pp. 1978-1990 ◽  
Author(s):  
J. Zheng ◽  
M.S. Hossain ◽  
D. Wang
Keyword(s):  
Bearing Capacity ◽  
Soft Clay ◽  
Bottom Layer ◽  
Design Approach ◽  
Rate Dependency ◽  
Soft Clays ◽  
Perfectly Plastic ◽  
Clay Deposits ◽  
Additional Resistance ◽  
Elastic Perfectly Plastic

Spudcan punch-through during installation and preloading process is one of the key concerns for the jack-up industry. This incident occurs in layered deposits, with new design approaches for spudcan penetration in sand-over-clay deposits reported recently. This paper reports a novel design approach for spudcan penetration in stiff-over-soft clay deposits. Large-deformation finite element (LDFE) analyses were carried out using the Coupled Eulerian–Lagrangian (CEL) approach. The clay was modelled using the extended elastic – perfectly plastic Tresca soil model allowing strain softening and rate dependency of the undrained shear strength. A detailed parametric study was undertaken, varying the strength ratio between bottom and top soil layers, the thickness of the top layer relative to the spudcan diameter, and degree of nonhomogeneity of the bottom layer. Existing data from centrifuge model tests were first used to validate the LDFE results, and then the measured and computed datasets were used to develop the formulas in the proposed design approach. The approach accounts for the soil plug in the bottom layer, and the corresponding additional resistance. Where there is the potential for punch-through, the approach provides estimations of the depth and bearing capacity at punch-through, the bearing capacity at the stiff–soft layer interface, and the bearing capacity in the bottom layer. Comparison shows that the punch-through method suggested in ISO standard 19905-1 provides a conservative estimate of the bearing capacity at punch-through, with guidelines provided to improve the method.

Embankments over Soft Clay Deposits: Contribution of Basal Reinforcement and Surface Sand Layer to Stability

2010 ◽  
Vol 136 (1) ◽  
pp. 260-264 ◽  
Author(s):  
Henrique Magnani Oliveira ◽  
Mauricio Ehrlich ◽  
Marcio S. S. Almeida
Keyword(s):  
Soft Clay ◽  
Sand Layer ◽  
Clay Deposits ◽  
Surface Sand

Slope instability and valley formation in Canadian soft clay deposits

1986 ◽  
Vol 23 (3) ◽  
pp. 261-270 ◽  
Author(s):  
Guy Lefebvre
Keyword(s):  
Slope Stability ◽  
Soft Clay ◽  
Slope Instability ◽  
Coarse Grained ◽  
Stability Conditions ◽  
Geological Time ◽  
Eastern Canada ◽  
Valley Bottom ◽  
Clay Deposits ◽  
Groundwater Regime

The purposes of the paper are to examine the deepening of valleys in clay deposits of Eastern Canada and in particular to look at the changes in the groundwater regime and slope stability conditions during valley formation. Field observations and laboratory testing indicate that the rate of valley deepening in Champlain clay deposits is of the order of only a few millimetres a year, owing to the low erodibility of the intact clay. The clay banks are, however, more erodible, owing to alteration and fissuration.The stratigraphy of Eastern Canadian clay deposits can be simplified by considering it to be a stratum of low permeabilityconfined between two boundary layers of relatively high permeability, which are the till layer at the base and a weathered crust or coarse-grained layer at the top. As the valley bottom get closer to the bottom till layer, the groundwater regime, and consequently the stability conditions, are modified. During the process of valley formation, the groundwater regime passes through astage where the conditions are rather detrimental to slope stability as it evolves toward conditions that enhance bank stability. Those changes in stability conditions happen over geological time more rapidly or less, depending on clay erodibility. Key words: soft clay, valley formation, slope stability, groundwater, erosion, erodibility.

Case studies of three-dimensional effects on the behaviour of test embankments

2009 ◽  
Vol 46 (11) ◽  
pp. 1356-1370 ◽  
Author(s):  
Guangfeng Qu ◽  
Sean D. Hinchberger ◽  
K. Y. Lo
Keyword(s):  
Soft Clay ◽  
Three Dimensional ◽  
Width Ratio ◽  
3D Analysis ◽  
Clay Deposits ◽  
3D Effects ◽  
Scale Test ◽  
Spread Footings ◽  
2D And 3D ◽  
Similar Soil

This paper uses both two-dimensional (2D) and three-dimensional (3D) finite element (FE) analyses to examine three cases involving the construction of full-scale test embankments to failure on soft clay deposits. By comparing the calculated fill thickness at failure from 2D and 3D analyses, it is shown that 3D effects are significant for all test fills, despite the dramatically different locations, fill thicknesses, and underlying clay deposits. In addition, the calculated undrained displacement and extent of failure from 3D analysis agree well with those measured in each case. The risk of neglecting 3D effects is highlighted by the analyses, where it is shown that failure to account for 3D effects while interpreting the response of a test embankment can lead to unsatisfactory performance of the actual long embankment. Finally, by comparing FE analysis results with well-known bearing capacity factors, it is shown that test embankments with a base length to width ratio less than 2 are more strongly influenced by 3D effects than spread footings on similar soil profiles. The analyses presented in this paper provide practical insight into some factors that should be taken into account for the design and construction of embankments and test fills on soft clay deposits.

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