The coefficient of earth pressure at rest

1993 ◽  
Vol 30 (4) ◽  
pp. 647-666 ◽  
Author(s):  
G. Mesri ◽  
T.M. Hayat
Keyword(s):  
Soft Clay ◽  
Earth Pressure ◽  
Stress Path ◽  
Vertical Stress ◽  
Deformation Condition ◽  
Granular Soils ◽  
Empirical Equations ◽  
Angle Of Internal Friction ◽  
Secondary Compression ◽  
Clay Deposits

Laboratory experiments on undisturbed specimens of a large number of soft clay deposits, as well as previous measurements on clays and granular soils, were used to examine and explain the magnitude and behavior of the coefficient of earth pressure at rest, K0: (i) after sedimentation – primary consolidation, (ii) during secondary-compression aging, (iii) after active or passive preshearing away from the laterally constrained condition, (iv) during a decrease in effective vertical stress, and (v) during an increase in effective vertical stress in the recompression or compression range, in terms of [Formula: see text], the slope of the effective horizontal [Formula: see text] versus effective vertical[Formula: see text] stress path. The behavior of K0 is explained using the concept of mobilized angle of friction in laterally constrained deformation condition. The Jaky equation provides, in terms of the angle of internal friction, a good estimate of K0 of sedimented, normally consolidated young clays and granular soils, as well as of [Formula: see text] of presheared clays and sands, and of densified granular soils that are subjected to laterally constrained compression from [Formula: see text]. Empirical equations provide reasonable estimates of K0 for clays and granular soils after secondary-compression aging, after preconsolidation by unloading, and for soft clay deposits that display a preconsolidation pressure [Formula: see text] greater than in situ effective vertical stress [Formula: see text]. Proposed empirical equations and methods successfully predict K0 of presheared clays. Key words: coefficient of earth pressure at rest, soft clays, granular soils, presheared soils, sampling and laboratory testing.

Unconventional concepts for dykes and dams on soft clay foundation

1984 ◽  
Vol 21 (3) ◽  
pp. 581-586
Author(s):  
O. Eide ◽  
S. Lacasse ◽  
B. Kjærnsli ◽  
P. S. Hafskjold
Keyword(s):  
Key Words ◽  
Soft Clay ◽  
Earth Pressure ◽  
Soil Improvement ◽  
Construction Time ◽  
Sloping Ground ◽  
Vertical Drains ◽  
Clay Deposit ◽  
Clay Deposits ◽  
Improvement Measures

As an alternative to a stage-construction embankment dyke equipped with vertical drains, two buttress-type concrete dams are proposed for deep, soft clay deposits where the building of embankment dykes would involve serious difficulties and sizable expenditures. These concepts avoid the loading of the soft clay deposit with high embankments and thus reduce problems of stability and settlement. High embankment dykes may not be feasible in the case of sloping ground, even gently so, because of the lack of stability in a flake-type sliding. The advantages of the proposed concept include the absence of soil improvement measures, shorter construction time, and reduced settlements. Specific drawbacks relate to the lack of experience with buttress-type dams on soft clay foundations. Key words: dam, clay, concrete, earth pressure, embankment, pile.

Secondary compression behavior of over-consolidated soft clay after surcharge preloading

2021 ◽  
Author(s):  
Jun Wang ◽  
Heng Zhuang ◽  
Lin Guo ◽  
Yuanqiang Cai ◽  
Mingfeng Li ◽  
...  
Keyword(s):  
Soft Clay ◽  
Compression Behavior ◽  
Secondary Compression ◽  
Surcharge Preloading

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.

Critical Insights in Laboratory Shear Wave Velocity Correlations of Clays

2021 ◽  
Author(s):  
Dania Elbeggo ◽  
Yannic Ethier ◽  
Jean-Sébastien Dubé ◽  
Mourad Karray
Keyword(s):  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Earth Pressure ◽  
Dynamic Parameter ◽  
Clay Deposits ◽  
Sample Disturbance ◽  
P Rat

Shear wave velocity is an important mechanical/dynamic parameter allowing the characterization of a soil in the elastic range (γ < 0.001 %). Thirty five existing laboratory correlations of small strains shear modulus or shear wave velocity were examined in this study and are grouped into different general forms based on their geotechnical properties. A database of 11 eastern Canadian clay deposits was selected and used for the critical insights. The effect of the coefficient of earth pressure at rest was also examined. A range of variation for each general form of correlation was determined to take the plasticity index and void ratio values of investigated sites into account. The analysis shows a significant scatter in normalized shear wave velocity values predicted by existing correlations and raises questions on the applicability of these correlations, especially for eastern Canadian clays. New correlations are proposed for Champlain clays based on laboratory measurement of shear wave velocity using the piezoelectric ring actuator technique, P-RAT, incorporated in consolidation cells. An analysis of P-RAT results reveals the sample disturbance effect and suggests an approach to correct the effect of disturbance on laboratory shear wave velocity measurements. The applicability of the proposed correlations, including the disturbance correction, is validated by comparison with in situ measurements using multi-modal analysis of surface waves (MMASW).

Closure to “Lateral Earth Pressure at Rest in Soft Clay”

1978 ◽  
Vol 104 (1) ◽  
pp. 146-148
Author(s):  
Karl Rainer Massarsch ◽  
Bengt B. Broms
Keyword(s):  
Soft Clay ◽  
Earth Pressure ◽  
Lateral Earth Pressure

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.

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