A Simplified Method for Analysis of Laterally Loaded Piles considering Cyclic Soil Degradation

This paper proposes a simplified method to analyze the bearing behavior of pile undergoing cyclic lateral load. Firstly, a modified strain model is proposed by utilizing the Duncan–Chang model to describe the stress-strain behavior of soils in the strain wedge. Then, a cyclic degradation model of soft clay considering the accumulation of plastic strain and pore water pressure is presented based on the cyclic triaxial test. Combining with the modified strain wedge model and degradation model of soil, a simplified method is established for the cyclic laterally loaded pile. The accuracy of the present method is verified by comparing it with existing model tests. The results show that the pile lateral displacement and strain wedge depth increase with the number of cycles and cyclic load amplitude. It is necessary to consider the effect of cumulative pore water pressure during the analysis of cyclic laterally loaded pile embedded in soft clay.

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Study on Reinforce Saturated Soft Clay Foundation with Dynamic Consolidation by Drainage

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.438-439.1171 ◽

2013 ◽

Vol 438-439 ◽

pp. 1171-1175

Author(s):

Zhi Li Sui ◽

Zhao Guang Li ◽

Xu Peng Wang ◽

Wen Li Li ◽

Tie Jun Xu

Keyword(s):

Pore Water ◽

Pore Water Pressure ◽

Water Pressure ◽

Soft Clay ◽

Soil Layer ◽

Good Effect ◽

Loading Test ◽

Test Plate ◽

Dynamic Consolidation ◽

Saturated Soft Clay

Dynamic consolidation method has been widely used in improving soft land, but always inefficient to saturated soft clay land, which is hard to improve, and even leads to rubber soil. Dynamic and drain consolidation method will deal with it well, with drainage system, pore-water can be expelled instantly from saturated soft clay as impacting. The pore-water pressure and earth pressure test in construction, the standard penetration test, plate loading test, geotechnical test after construction, which are all effective methods for effect testing. There is a comprehensive detection through different depth of soil layer with different detecting means on construction site. The results show that improving saturated soft clay land with dynamic and drain consolidation method has obtained good effect, and the fruit can be guidance for such construction in the future.

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Effective stress paths and yielding in soft clays below embankments

Canadian Geotechnical Journal ◽

10.1139/t85-048 ◽

1985 ◽

Vol 22 (3) ◽

pp. 357-374 ◽

Cited By ~ 22

Author(s):

D. J. Folkes ◽

J. H. A. Crooks

Keyword(s):

Pore Water ◽

Effective Stress ◽

Strain Softening ◽

Pore Water Pressure ◽

Water Pressure ◽

Soft Clay ◽

Stress Path ◽

Excess Pore Water Pressure ◽

Soft Clays ◽

Effective Stress Path

Current methods of predicting the response of soft clays to surface loading are often unsuccessful because the assumed constitutive relationships, including effective stress path behaviour, are incorrect. In particular, the transition from small-strain to large-strain behaviour (i.e. yielding) is frequently not taken into account. Recent laboratory testing has demonstrated that the behaviour of soft clays is largely controlled by yielding. The locus of effective stress states causing yield is known as the yield envelope (YE).The effective stress paths (ESP's) in soft clay foundations below the centre of six fills were determined from computed total stresses and measured pore-water pressures. Yield behaviour is clearly indicated by ESP shapes. The yield envelopes inferred from analyses of field data are similar to those obtained from laboratory testing. Effective stress path shapes vary widely, depending on a variety of factors, including imposed stress level, rate of construction, and boundary drainage conditions. This finding contradicts an earlier conclusion that soft clay behaviour can be characterized by a single ESP. Because of the wide range of possible ESP shapes, the parameters [Formula: see text] does not provide an adequate basis for determining the effective stress state in a soft clay.The ESP/YE analyses indicate that yield can occur either during loading or during excess pore-water pressure dissipation following completion of loading. Yield of sensitive soils during loading is usually followed by strain softening. However, in some soils, dilatant behaviour appears to occur. Yield during dissipation of excess pore-water pressure is characterized by a dramatic change in cv and increased compressibility. Key words: soft clay, yield, effective stress paths, field behaviour, strain softening, rate of consolidation.

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Calculation of Consolidation Coefficient and Percent Consolidation from Measured Pore Water Pressure of Soft Clay

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.250-253.1889 ◽

2011 ◽

Vol 250-253 ◽

pp. 1889-1892

Author(s):

Yong Mou Zhang ◽

Jian Chang Zhao

Keyword(s):

Pore Water ◽

Pore Water Pressure ◽

Water Pressure ◽

Soft Soil ◽

Soft Clay ◽

Coefficient Of Consolidation ◽

Consolidation Process ◽

Consolidation Coefficient

Consolidation coefficient and percent consolidation of soft clay were calculated according to the measured pore water pressure of a project in Pudong Shanghai. Calculated coefficient of consolidation was one magnitude larger than the experimental one. This was in conformity with the actual consolidation process of dynamically-consolidated soft soil.

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Modelling unanticipated pore-water pressures in soft clays

Canadian Geotechnical Journal ◽

10.1139/t94-088 ◽

1994 ◽

Vol 31 (5) ◽

pp. 773-778 ◽

Cited By ~ 31

Author(s):

Jianhua Yin ◽

James Graham ◽

Jack I. Clark ◽

Longjun Gao

Keyword(s):

Pore Water ◽

Pore Water Pressure ◽

Water Pressure ◽

Creep Behaviour ◽

Soft Clay ◽

Field Observations ◽

Soft Clays ◽

Secondary Compression ◽

Pore Water Pressures ◽

Clay Layers

Field observations in thin soft clay layers may show pore-water pressures that increase for some time after the loading is applied. Reasons for these observations are not well understood. The paper shows how an elastic viscoplastic constitutive model incorporated into the consolidation equation can predict these pore-water pressure increases in soils that exhibit significant creep behaviour (or secondary compression). The phenomenon has been related to relaxation in regions of the profile from which drainage has not yet begun. Key words : clay, consolidation, creep, secondary compression, viscous, relaxation, pore-water pressure, elastic–plastic.

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