Influence of flood-induced scour on dynamic impedances of pile groups considering the stress history of undrained soft clay

2017 ◽  
Vol 96 ◽  
pp. 76-88 ◽  
Author(s):  
Fayun Liang ◽  
Hao Zhang ◽  
Maosong Huang
Keyword(s):  
Soft Clay ◽  
Pile Groups ◽  
Stress History ◽  
History Of

Determining Preconsolidation Pressure of the Lakeside New District Soft Clay of Hefei Based on Casagrande Method by Matlab

2013 ◽  
Vol 291-294 ◽  
pp. 1113-1116
Author(s):  
Yan Shao ◽  
Chang Yong Li ◽  
Yuan Wei
Keyword(s):  
Soft Clay ◽  
Least Square Method ◽  
Least Square ◽  
Compression Curve ◽  
Stress History ◽  
Important Index ◽  
Preconsolidation Pressure ◽  
Quartic Polynomial ◽  
History Of ◽  
Calculation Parameter

The preconsolidation pressure is an important index to determine the stress history of soil and also a major calculation parameter for the analysis of soil stratum’s deformation in the different stress history. Casagrade method is worldwide applied to determine the preconsolidation pressure. On the basis of research on consolidation test about the lakeside new district soft clay of Hefei by high pressure consolidation apparatus, and conformed to Casagrande method, the paper adopts quartic polynomial and least square method to fit the compression curve, and the preconsolidation pressure of the lakeside new distract soft clay of Hefei is determined by matlab software. The result provides reference for the calculation of foundation settlement considering stress history.

Study on Assessing Method of Stress History of Marine Soft Clay

2012 ◽  
Vol 616-618 ◽  
pp. 1741-1744
Author(s):  
Sheng Jie Di ◽  
Zhi Gang Shan ◽  
Ming Yuan Wang
Keyword(s):  
Soft Clay ◽  
Empirical Method ◽  
Foundation Engineering ◽  
Engineering Project ◽  
Stress History ◽  
Vane Shear Test ◽  
Soil Stress ◽  
Good Consistency ◽  
History Of ◽  
Assessing Method

The vane shear test (VST) is comprehensively analyzed by means of empirical method, which on soft ground of one offshore foundation engineering project in Jiangsu province of China. The methods of judgment of soil stress history are summarized. Based on the shear strength of soft clay, consolidation state of the soft clay is obtained. The conclusion shows that it belongs to slight over-consolidation state. In the meantime, the two evaluation methods are comparatively analyzed. In the depth more than 5 m, the curves of over consolidation ratio (OCR) of two methods show a good consistency. The methods and applications can provide useful reference for engineers.

Extreme scour effects on the buckling of bridge piles considering the stress history of soft clay

2015 ◽  
Vol 77 (2) ◽  
pp. 1143-1159 ◽  
Author(s):  
Fayun Liang ◽  
Hao Zhang ◽  
Maosong Huang
Keyword(s):  
Soft Clay ◽  
Stress History ◽  
History Of

scholarly journals The relationship between sea-level change, soil formation and stress history of a very soft clay deposit

2019 ◽  
Vol 5 (3) ◽  
pp. 461-479 ◽  
Author(s):  
Fernando A.B. Danziger ◽  
◽  
Graziella M.F. Jannuzzi ◽  
Ian S.M. Martins ◽  
Keyword(s):  
Sea Level ◽  
Soft Clay ◽  
Soil Formation ◽  
Sea Level Change ◽  
Stress History ◽  
Clay Deposit ◽  
Level Change ◽  
History Of ◽  
The Relationship

scholarly journals Numerical Study of Laterally Loaded Piles in Soft Clay Overlying Dense Sand

2021 ◽  
Vol 7 (4) ◽  
pp. 730-746
Author(s):  
Amanpreet Kaur ◽  
Harvinder Singh ◽  
J. N. Jha
Keyword(s):  
Layer Thickness ◽  
Soft Clay ◽  
Bending Moment ◽  
Layered Soil ◽  
Clay Layer ◽  
Pile Groups ◽  
Dense Sand ◽  
Lateral Capacity ◽  
Laterally Loaded ◽  
Pile Length

This paper presents the results of three dimensional finite element analysis of laterally loaded pile groups of configuration 1×1, 2×1 and 3×1, embedded in two-layered soil consisting of soft clay at liquid limit overlying dense sand using Plaxis 3D. Effects of variation in pile length (L) and clay layer thickness (h) on lateral capacity and bending moment profile of pile foundations were evaluated by employing different values of pile length to diameter ratio (L/D) and ratio of clay layer thickness to pile length (h/L) in the analysis. Obtained results indicated that the lateral capacity reduces non-linearly with increase in clay layer thickness. Larger decrease was observed in group piles. A non-dimensional parameter Fx ratio was defined to compare lateral capacity in layered soil to that in dense sand, for which a generalized expression was derived in terms of h/L ratio and number of piles in a group. Group effect on lateral resistance and maximum bending moment was observed to become insignificant for clay layer thickness exceeding 40% of pile length. For a fixed value of clay layer thickness, lateral capacity and bending moment in a single pile increased significantly with increase in pile length only up to an optimum embedment depth in sand layer which was found to be equal to three times pile diameter and 0.21 times pile length for pile with L/D 15. Scale effect on lateral capacity has also been studied and discussed. Doi: 10.28991/cej-2021-03091686 Full Text: PDF

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.

scholarly journals Scour Effects on the Lateral Behavior of a Large-Diameter Monopile in Soft Clay: Role of Stress History

2019 ◽  
Vol 7 (6) ◽  
pp. 170 ◽  
Author(s):  
Ben He ◽  
Yongqing Lai ◽  
Lizhong Wang ◽  
Yi Hong ◽  
Ronghua Zhu
Keyword(s):  
Large Diameter ◽  
Soft Clay ◽  
Small Diameter ◽  
Initial Stiffness ◽  
Stress History ◽  
Soil Stiffness ◽  
Hypoplastic Model ◽  
History Effects ◽  
Conservative Estimation ◽  
Lateral Behavior

Scouring of soil around large-diameter monopile will alter the stress history, and therefore the stiffness and strength of the soil at shallow depth, with important consequence to the lateral behavior of piles. The existing study is mainly focused on small-diameter piles under scouring, where the soil around a pile is analyzed with two simplified approaches: (I) simply removing the scour layers without changing the strength and stiffness of the remaining soils, or (II) solely considering the effects of stress history on the soil strength. This study aims to investigate and quantify the scour effect on the lateral behavior of monopile, based on an advanced hypoplastic model considering the influence of stress history on both soil stiffness and strength. It is revealed that ignorance about the stress history effect (due to scouring) underestimates the extent of the soil failure wedge around the monopile, while overestimates soil stiffness and strength. As a result, a large-diameter pile (diameter D = 5 m) in soft clay subjected to a souring depth of 0.5 D has experienced reductions in ultimate soil resistance and initial stiffness of the p-y curves by 40% and 26%, and thus an increase of pile head deflection by 49%. Due to the inadequacy to consider the stress history effects revealed above, the existing approach (I) has led to non-conservative estimation, while the approach (II) has resulted in an over-conservative prediction.

Effect of stress history of saturated clay on engineering behaviour of an energy pile

2020 ◽  
pp. 1-10
Author(s):  
Di Wu ◽  
Han-Long Liu ◽  
Gang-Qiang Kong ◽  
Hossam Abuel-Naga
Keyword(s):  
Stress History ◽  
Energy Pile ◽  
Saturated Clay ◽  
History Of
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