Impact of Shear Stress on Strain and Pore Water Pressure Behavior of Intact Soft Clay Under Principal Stress Rotation

2014 ◽  
Vol 37 (3) ◽  
pp. 20120189 ◽  
Author(s):  
Zhou Jian ◽  
Xu Changjie
Keyword(s):  
Shear Stress ◽  
Principal Stress ◽  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Soft Clay ◽  
Principal Stress Rotation ◽  
Pressure Behavior ◽  
Stress Rotation

scholarly journals Influence of Intermediate Principal Stress on Undrained Behavior of Intact Clay under Pure Principal Stress Rotation

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Jian Zhou ◽  
Jiajia Yan ◽  
Changjie Xu ◽  
Xiaonan Gong
Keyword(s):  
Pore Pressure ◽  
Principal Stress ◽  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Soft Clay ◽  
Shear Stiffness ◽  
Intermediate Principal Stress ◽  
Principal Stress Rotation ◽  
Stress Rotation

This study presents the accumulations of the excess pore water pressure and the deformation as well as the noncoaxial behavior of intact soft clay subjected to pure principal stress rotation. Series of tests were carried out by using a dynamic hollow cylinder apparatus to highlight the influence of intermediate principal stress parameterb. It was found that the rate of PWP evolution was greatly influenced byb, but the influence was not monotonous. Specimens under the conditionb= 0.75 had the highest accumulation of pore water pressure while under the conditionb= 0 had the strongest resistance to the pore pressure generation. PWP accumulated mainly in the first cycle. The failure of specimens under principal stress rotation was controlled by the strain other than the pore pressure. The shear stiffness decreased more quickly with higherbvalue. The direction of the principal strain increment was strongly dependent on the principal stress increment orientation and less influenced by thebvalue and the number of cycles.

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

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.

scholarly journals Effect of Wetting-Drying Cycle on the Deformation and Seepage Behaviors of Rock Masses around a Tunnel

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Qingzhen Guo ◽  
Haijian Su ◽  
Hongwen Jing ◽  
Wenxin Zhu
Keyword(s):  
Rock Mass ◽  
Principal Stress ◽  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Water Inrush ◽  
Surrounding Rock ◽  
Tunnel Excavation ◽  
Cycle Number ◽  
Simulation Results

Water inrush caused by the wetting-drying cycle is a difficult problem in tunnel excavation. To investigate the effect of the wetting-drying cycle on the stability of the tunnel surrounding rock, physical experiments and numerical simulations regarding the process of tunnel excavation with different wetting-drying cycle numbers were performed in this study. The evolutions of stress, displacement, and pore water pressure were analyzed. With the increase in cycle number, the pore water pressure, vertical stress, and top-bottom approach of the tunnel surrounding rock increase gradually. And the increasing process could be divided into three stages: slightly increasing stage, slowly increasing stage, and sharply increasing stage, respectively. The failure process of the surrounding rock under the wetting-drying cycle gradually occurs from the roof to side wall, while the baseplate changes slightly. The simulation results showed that the maximum principal stress in the surrounding rock mass of the tunnel increases, while the minimum principal stress decreases. Furthermore, the displacement of the rock mass decreases gradually with the increasing distance from the tunnel surface. By comparing the simulation results with the experimental results, well consistency is shown. The results in this study can provide helpful references for the safe excavation and scientific design of a tunnel under the wetting-drying cycle.

Effective stress paths and yielding in soft clays below embankments

1985 ◽  
Vol 22 (3) ◽  
pp. 357-374 ◽  
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.

scholarly journals One-way cyclic deformation behavior of natural soft clay under continuous principal stress rotation

2017 ◽  
Vol 57 (6) ◽  
pp. 1002-1013 ◽  
Author(s):  
Yuke Wang ◽  
Yufeng Gao ◽  
Bing Li ◽  
Hongyuan Fang ◽  
Fuming Wang ◽  
...  
Keyword(s):  
Principal Stress ◽  
Cyclic Deformation ◽  
Deformation Behavior ◽  
Soft Clay ◽  
Principal Stress Rotation ◽  
Stress Rotation

Influence of principal stress rotation of unequal tensile and compressive stress amplitudes on characteristics of soft clay

2017 ◽  
Vol 14 (2) ◽  
pp. 369-381 ◽  
Author(s):  
Yang Shen ◽  
Xin Wang ◽  
Han-long Liu ◽  
Wen-han Du ◽  
Bao-guang Wang ◽  
...  
Keyword(s):  
Principal Stress ◽  
Compressive Stress ◽  
Soft Clay ◽  
Principal Stress Rotation ◽  
Stress Rotation

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

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.

Modelling unanticipated pore-water pressures in soft clays

1994 ◽  
Vol 31 (5) ◽  
pp. 773-778 ◽  
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.

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

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Yuzhe Yang ◽  
Xiaodong Gao ◽  
Wenbing Wu ◽  
Kangyu Xing
Keyword(s):  
Pore Water ◽  
Pore Water Pressure ◽  
Lateral Displacement ◽  
Water Pressure ◽  
Soft Clay ◽  
Degradation Model ◽  
Laterally Loaded Pile ◽  
Simplified Method ◽  
Strain Wedge ◽  
Laterally Loaded

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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