Numerical Simulation of Pile-Bucket Foundation under Horizontal Load

2012 ◽  
Vol 460 ◽  
pp. 169-174
Author(s):  
Wen Bai Liu ◽  
Liang Yang ◽  
Chen Xia Zhu
Keyword(s):  
Failure Surface ◽  
Horizontal Load ◽  
Soil Pressure ◽  
Passive Region ◽  
Deep Soil ◽  
Maximum Displacement ◽  
Bucket Foundation ◽  
Load Line ◽  
Soil Stress ◽  
Pressure Changes

The pile-bucket foundation is a new kind of foundation. In this paper, the ABAQUS software was used to analyze the soil displacement field and the soil stress field surrounding of the pile-bucket foundation under the multi-cycle horizontal loading. Under the horizontal load, the active area of soil separated from the basics; the passive region takes the shape of a parabolic ring of soil wedge rotate failure surface. The maximum displacement was in the direction of horizontal load line on the surface of soil near the bucket. Horizontal and vertical soil pressure changes are concentrated under the surface of the soil near the bucket, and the maximum horizontal soil stress was in the deep soil around the bucket. There is a point of inflection between 1/3 and 1/2 of the pile into soil , and the soil pressure that upper and lower the point increased in the opposite direction. The horizontal forced resistance of the foundation mainly distributed under the bucket and 1/2 of the pile into soil .The conclusion could provide a reference basis for the analysis of bearing mechanism and destruction characters of pile-bucket foundation

Variation for Soil Stress on CPTU Model Test

2010 ◽  
Vol 44-47 ◽  
pp. 2597-2601
Author(s):  
Yan Chun Tang ◽  
Gao Tou Meng
Keyword(s):  
Stress Field ◽  
Maximum Stress ◽  
Clay Soil ◽  
Cell Layer ◽  
Compression Stress ◽  
Soil Pressure ◽  
Piezocone Penetration Test ◽  
Main Stress ◽  
Saturated Clay ◽  
Soil Stress

Through a series of Piezocone Penetration Test (CPTU) model tests with saturated clay soil, by CPTU probe penetrating soil stress measured by soil pressure mini-cells embedded into soil has been acquired, the variation rules of soil stress by penetrating has been analyzed, the results show that with probe close to the second cell layer, the stress measured by the cells has been increased rapidly; when probe has arrived at the position of the second cell layer, the maximum stress value has been attained; and with probe away from the second cell layer, the stress value has been decreased rapidly. Based on the achieved soil stress value, the axial and radial subsidiary stress field causing by penetrating has been acquired, the conclusions can be obtained that the main stress style of the axial subsidiary stress is compression stress, around the probe the highest stress field has been occurred; the stress style of the radial subsidiary stress is compression stress, this phenomenon shows that by penetrating the compaction effect of the soil around the probe has been created; during the course of penetrating, the radial subsidiary stress is less than the axial subsidiary stress obviously. The achieved result can provide a foundation for further study for CPTU mechanism.

Three-Dimensional Finite Element Analysis on the Bearing Capacity of Bucket Foundation with Different Ratios of Diameter to Height

2014 ◽  
Vol 488-489 ◽  
pp. 689-695
Author(s):  
Shuai Liu ◽  
Wen Bai Liu ◽  
Liang Yang
Keyword(s):  
Bearing Capacity ◽  
Three Dimensional ◽  
Vertical Displacement ◽  
Ultimate Bearing Capacity ◽  
Displacement Curve ◽  
Maximum Displacement ◽  
Element Analysis ◽  
Bucket Foundation ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

The ABAQUS software is used for simulating the vertical bearing capacity of bucket foundation of different ratios of diameter to height and the analysis for the stress and displacement distribution and load-displacement curve. When the bucket foundation is under pressure, the vertical stress of the soil distribution changes from the bottom to the top, and then spreads to most part of the soil in the bucket foundation. The vertical displacement of the soil develops from the top of foundation and spreads inside, then expands to the outside range, the maximum displacement occurs both at the bottom and inside. According to the analysis of the ultimate bearing capacity of the bucket foundation, it could be found that when the height of the bucket foundation remains unchanged, the ultimate bearing capacity increases with the increasing ratio of diameter to height. If the ratio of diameter to height is less than 1.2, the ultimate strength increases significantly. If the ratio of diameter to height is greater than 1.2, the increasing speed of the ultimate bearing capacity changes slowly. When the diameter of the bucket foundation is constant, the ultimate bearing capacity decreases as the ratio of diameter to height gradually increases, and it decreases at a homogeneous speed. So the ratio of diameter to height 1.2 can be used as the optimum point of the ratio of diameter to height of the bucket foundation.

In situ shear tests of soil blocks with roots

1998 ◽  
Vol 35 (4) ◽  
pp. 579-590 ◽  
Author(s):  
Tien H Wu ◽  
Alex Watson
Keyword(s):  
Shear Strength ◽  
Root System ◽  
Tensile Force ◽  
Failure Surface ◽  
Soil Reinforcement ◽  
Shear Tests ◽  
Maximum Displacement ◽  
Shearing Resistance ◽  
Simplified Procedures

In situ shear tests were performed on soil blocks that contained roots to study the contribution of roots to the shear strength in a case where the shear deformation is not constrained to a thin zone. The shearing resistance of the soil-root system, the tensile force in selected roots, and the deformation of the soil block were measured. The roots were exposed after the test and their positions were determined and used to estimate the initial positions. The root force and the shearing resistance of the soil-root system were estimated with known solutions and compared with measured root force and shearing resistance. None of the roots that passed through the shear zone failed in tension at the maximum displacement. As a consequence, the root resistance is much less than that found in a case where the failure surface is restricted to the boundary between a weak soil and a firm base and where roots are anchored in the firm base and fail in tension. Simplified procedures for estimating root forces are suggested for the case of a thick shear zone.Key words: in situ test, roots, shear strength, slope stability, soil reinforcement, soil–root interaction.

Model Test Study on the Effect of Horizontal Load on the Vertical Bearing Capacity of Disk Pile

2011 ◽  
Vol 368-373 ◽  
pp. 2571-2574
Author(s):  
Cheng Yuan Lu ◽  
Jin Jin Li ◽  
Fan Li Meng
Keyword(s):  
Bearing Capacity ◽  
Bending Moment ◽  
Horizontal Displacement ◽  
Initial Time ◽  
Horizontal Load ◽  
Vertical Load ◽  
Soil Pressure ◽  
Test Study ◽  
Vertical Bearing ◽  
Vertical Bearing Capacity

A group of model tests were designed to study the effect of horizontal load on the vertical bearing capacity of disk pile. Three double-disk piles were used in the test, and the distance of the two disks is 5 times as the disk diameter. Drew a horizontal load H=100N/200N/300N on the top of pile1/2/3 respectively, and put on the vertical load stage by stage, then studied the differences of three piles’ bearing properties such as changes of the pile bending moment, the horizontal and vertical deformation on the top, and soil pressure around the pile. Experiment showed that when the horizontal load is quite small, the existence of horizontal load has little to do with vertical bearing capacity. When the load reached a certain level, the p-∆ effect under the vertical load will significantly affect the vertical bearing capacity of the pile. Especially during the initial time while there is a large horizontal displacement or rotation generated by the horizontal load, the pile’s bearing capacity is controlled by the horizontal displacement.

Upper-bound solutions of three-dimensional passive earth pressures

2005 ◽  
Vol 42 (5) ◽  
pp. 1449-1460 ◽  
Author(s):  
S Škrabl ◽  
B Macuh
Keyword(s):  
Failure Mechanism ◽  
Upper Bound ◽  
Limit Analysis ◽  
Central Body ◽  
Three Dimensional ◽  
Failure Surface ◽  
Outer Side ◽  
Soil Pressure ◽  
Upper Bound Method ◽  
The Cross

This paper presents a novel approach to the determination of passive soil pressures: using the upper-bound method within the framework of limit analysis theory. It is based on a three-dimensional, kinematically admissible, rotational, hyperbolical failure mechanism. The failure mechanism is composed of the central and two lateral bodies, which are connected by a common velocity field. This approach is similar to two-dimensional stability analyses, where the log spiral potential failure surface is considered. The front surface of the central body interacts with the retaining wall; the upper surface can be loaded by surcharge loading; and the log spiral segment defines the curved failure surface of the central part. The cross sections of the lateral bodies are in agreement with the cross section of the central body. On the outer side, they are laterally bounded by a curved and kinematically admissible hyperbolic surface, which is defined by enveloping the hyperbolical half cones and part of the case surface of the leading half cone. The results give values for the passive soil pressure coefficients that are for most cases lower than the values determined by the upper-bound method of limit analysis for a translational failure mechanism, as published in the literature.Key words: limit analysis, earth pressure, passive pressure, failure surface, soil–structure interaction.

Analysis on Pile-Soil Stress Ratio of Composite Foundation with Sparse Capped-Piles under Lime-Soil Embankment Load

2014 ◽  
Vol 501-504 ◽  
pp. 124-131 ◽  
Author(s):  
Wei Zheng Liu ◽  
Jun Hui Zhang ◽  
Hao Zhang
Keyword(s):  
Stress Ratio ◽  
Load Transfer ◽  
Stress Transfer ◽  
Composite Foundation ◽  
Transfer Model ◽  
Soil Pressure ◽  
Soil Stress ◽  
Rigid Pile Composite Foundation ◽  
Embankment Height ◽  
Piled Embankment

The combined effect of the embankment fill, piles and caps, and foundation soils on the load transfer characteristics of sparse capped-piled embankment is very significant. Using the modified cylindrical shear stress transfer model based on Marston soil pressure theory, a new calculation method for pile-soil stress ratio of sparse rigid pile composite foundation incorporating the arching effect in lime-soil and soil-pile interaction was presented. The presented method is verified by comparison between analytical solutions and the observed results from a practical project. In addition, a parametric study was also conducted to evaluate the influence of the embankment height, the cohesion of fill and pile-soil stiffness ratio on the pile-soil stress ratio.

scholarly journals Stability Analysis of Expansive Soil Slope Considering Seepage Softening and Moistening Expansion Deformation

Water ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1678
Author(s):  
Siyi Zhao ◽  
Zhenming Shi ◽  
Ming Peng ◽  
Yanni Bao
Keyword(s):  
Expansive Soil ◽  
Failure Surface ◽  
Horizontal Stress ◽  
Soil Slope ◽  
Maximum Displacement ◽  
Language Program ◽  
Order Of Magnitude ◽  
Fortran Language ◽  
Matrix Suction ◽  
Unsaturated Seepage

Expansive soil is a kind of clay soil that expands rapidly after being immersed in water and shrinks significantly after losing water. The expansive soil slopes exposed to the atmosphere are in the process of continuous dry and wet cycles and are extremely unstable under the conditions of rainfall. Based on saturated-unsaturated seepage theory, the unsaturated seepage process and humidification process of the expansive soil slope under rainfall were simulated, and a related FORTRAN language program was developed. The effects of matrix suction changes, seepage softening, and moistening expansion during the seepage process were considered. The effects of strength attenuation, seepage softening, and moistening expansion on the overall stability of the expansive soil slope were analyzed. The results show that under the action of rainfall, the failure mode of the expansive soil slope after multiple dry-wet cycles is shallow collapse, and the failure surface is located in the weathered area, which is quite different from the traction landslide of the homogeneous expansive soil slope. After considering the moistening expansion and softening effects, the maximum displacement of the slope increased by an order of magnitude, and the safety factor decreased significantly. The significant increase in the horizontal stress of the lower half slope is the main reason for the landslide. The research results well explain the special tractive and shallow properties of typical expansive soil landslides.

Study on the Bearing Mechanism of Bucket Foundation for Offshore-Wind Turbine in Soft Clay

2011 ◽  
Vol 71-78 ◽  
pp. 1795-1804
Author(s):  
Jian Feng Wang ◽  
Hai Tao Dai ◽  
Ming Qin
Keyword(s):  
Large Scale ◽  
Soft Clay ◽  
Bending Moment ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Horizontal Load ◽  
Vertical Load ◽  
Bucket Foundation ◽  
Finite Element Software ◽  
Moment Load

Based on numerical platform of large-scale finite element software, this paper investigates the function mechanisms of vertical load, horizontal load, and bending moment load of soft-clay-base bucket foundation. Then the corresponding load bearing characteristics of each load type of soft-clay-base bucket foundation are determined.

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