scholarly journals Ultimate Bearing Capacity of Strip Foundations in Unsaturated Soils considering the Intermediate Principal Stress Effect

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Qing Yan ◽  
Junhai Zhao ◽  
Changguang Zhang ◽  
Jintai Wang
Keyword(s):  
Bearing Capacity ◽  
Principal Stress ◽  
Unsaturated Soils ◽  
Matric Suction ◽  
Ultimate Bearing Capacity ◽  
Intermediate Principal Stress ◽  
Shallow Foundations ◽  
Hyperbolic Function ◽  
Stress Effect ◽  
Intermediate Principal Stress Effect

The reasonable determination of ultimate bearing capacity is crucial to an optimal design of shallow foundations. Soils surrounding shallow foundations are commonly located above the water table and are thus in an unsaturated state. The intermediate principal stress has an improving effect on the unsaturated soil strength. In this study, the ultimate bearing capacity formulation of strip foundations in unsaturated soils is presented by using Terzaghi’s theory. The unified shear strength equation of unsaturated soils under a plane strain condition is utilized to capture the intermediate principal stress effect. Furthermore, two profiles of matric suction are considered and a hyperbolic function of the friction angle related to matric suction (φb) is adopted to describe strength nonlinearity. The validity of this study is demonstrated by comparing it with model tests and a theoretical solution reported in the literature. Finally, parameter studies are conducted to investigate the effects of intermediate principal stress, matric suction, and base roughness on the ultimate bearing capacity of strip foundations. Besides, the effect of strength nonlinearity is discussed with two methods representing the angle φb.

Analysis of Axial Bearing Capacity of Concrete-Filled Steel Tube Hollow Columns

2013 ◽  
Vol 639-640 ◽  
pp. 770-773
Author(s):  
Xiao Yan Luo ◽  
Wei Ping Liu
Keyword(s):  
Bearing Capacity ◽  
Principal Stress ◽  
Yield Criterion ◽  
Steel Tube ◽  
Ultimate Bearing Capacity ◽  
Intermediate Principal Stress ◽  
Stress Effect ◽  
Concrete Filled Steel Tube ◽  
Effect Parameter ◽  
Intermediate Principal Stress Effect

Based on the triple shear unified yield criterion, the mechanical behavior of the concrete-filled steel tube columns was analyzed. The calculation formulas of axial bearing capacity of the concrete-filled steel tube columns were deduced with considerations of the restriction effects of steel tube and the effects of the intermediate principal stressed. The results show that the intermediate principal stress effect parameter b has influences on the ultimate bearing capacity. With the increase of the intermediate principal stress effect parameter b, the ultimate bearing capacity of the concrete-filled steel tube columns increases too. The results show that formula deduced in the paper has good applicability and the solution has an important practical value.

scholarly journals Safety Factor of Unsaturated Soil Slopes considering the Intermediate Principal Stress Effect and Different Profiles of Matric Suction

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Zhaoxin Li ◽  
Changguang Zhang ◽  
Jingyuan Zhao ◽  
Qing Yan
Keyword(s):  
Shear Strength ◽  
Principal Stress ◽  
Safety Factor ◽  
Unsaturated Soil ◽  
Unsaturated Soils ◽  
Matric Suction ◽  
Intermediate Principal Stress ◽  
Stress Effect ◽  
Soil Slopes ◽  
The Stability

Profiles of matric suction are critical for assessing the stability of unsaturated soil slopes, and the strength of unsaturated soils is affected by the intermediate principal stress. This study presents a theoretical formulation of safety factor for infinite unsaturated soil slopes under four different profiles of matric suction using the limit equilibrium method. The unified shear strength equation under plane strain conditions is adopted to capture the effect of intermediate principal stress on the strength of unsaturated soils. The proposed formulation of safety factor is found to have good comparability and broad applicability. The validity of the proposed formulation is demonstrated by comparing its predictions with the results of the extended shear strength method and the finite element method available in the literature. Parametric studies show that the effect of intermediate principal stress on the stability of unsaturated soil slopes is significant; the difference of safety factor among four suction profiles is pronounced, and the safety factor is highest for a linear suction profile. In addition, the safety factor changes with the infiltration depth in two stages, decreases with the slope angle, and increases with effective strength parameters. The results of this study are capable of providing beneficial guidance for optimization designs and disaster preventions of unsaturated soil slopes.

Mechanics Behavior of Concrete-Filled Square Steel Tube Columns

2012 ◽  
Vol 256-259 ◽  
pp. 662-665
Author(s):  
Xiao Yan Luo ◽  
Wei Ping Liu
Keyword(s):  
Bearing Capacity ◽  
Principal Stress ◽  
Analytical Method ◽  
Yield Criterion ◽  
Steel Tube ◽  
Intermediate Principal Stress ◽  
Stress Effect ◽  
Effect Parameter ◽  
Intermediate Principal Stress Effect ◽  
Square Steel Tube

This study presents a simplified analytical method for predicting the ultimate strength of compressed concrete filled square steel tube columns based on the triple shear unified yield criterion. Based on the triple shear unified yield criterion theory solutions of thick tube, the calculation formulas of axial bearing capacity of the concrete-filled square steel tube columns were deduced with considerations of the restriction effects of steel tube and the effects of the intermediate principal stressed. The results show that the intermediate principal stress effect parameter b has influences on the ultimate bearing capacity. The formulas in the paper have significance in exerting material potential and save material.

The Changing Rule of Rock Strength under True Triaxial Condition

2014 ◽  
Vol 522-524 ◽  
pp. 1410-1413
Author(s):  
Ze Kang Wen ◽  
Ke Min Wei ◽  
Jia Quan Hu ◽  
You Ling Fang
Keyword(s):  
Principal Stress ◽  
Rock Strength ◽  
Quadratic Function ◽  
Intermediate Principal Stress ◽  
Stress Effect ◽  
True Triaxial Test ◽  
True Triaxial ◽  
Minimum Principal Stress ◽  
Stress Coefficient ◽  
Intermediate Principal Stress Effect

The intermediate principal stress effect of the rock has been demonstrated. By analyzing true triaxial test results of Dunham dolomite and Mizuho trachyte, we studied relationship between minimum principal stress and the rock strength under the same intermediate principal stress coefficient, and the relationship between intermediate principal stress and the rock strength under the same minimum principal stress condition. Research shows that the minimum principal stress has a linear relation with the rock strength, the intermediate principal stress coefficient of a quadratic function relation with the rock strength. And the mathematic expression of the intermediate principal stress effect function was calculated.

Study on the Ultimate Pullout Force of Prestressed Cable Based on Triple Shear Unified Yield Criterion

2012 ◽  
Vol 594-597 ◽  
pp. 840-843
Author(s):  
Xiao Yan Luo ◽  
Wei Ping Liu
Keyword(s):  
Principal Stress ◽  
Yield Criterion ◽  
Intermediate Principal Stress ◽  
Stress Effect ◽  
Pullout Force ◽  
Grouting Pressure ◽  
Effect Parameter ◽  
Ultimate Equilibrium ◽  
Intermediate Principal Stress Effect ◽  
Prestressed Cable

Based on the triple shear unified yield criterion and the ultimate equilibrium principle, the ultimate pullout force of prestressed cable is studied. The ultimate pullout force of prestressed cable is related to the rock type, the shapes of rapture surface, grouting pressures and compressive strength of rock, etc. The results show that the intermediate principal stress effect parameter b have influences on the ultimate pullout force of prestressed cable. With the increase of the intermediate principal stress effect parameter b, the ultimate pullout force of prestressed cable increases too. When the grouting pressure increases, the ultimate pullout force of prestressed cable increases also.

Unified Solution of Coulomb’s Active Earth Pressure for Unsaturated Soils without Crack

2012 ◽  
Vol 170-173 ◽  
pp. 755-761 ◽  
Author(s):  
Wen Biao Liang ◽  
Jun Hai Zhao ◽  
Yan Li ◽  
Chang Guang Zhang ◽  
Su Wang
Keyword(s):  
Principal Stress ◽  
Unsaturated Soils ◽  
Retaining Wall ◽  
Research Result ◽  
Earth Pressure ◽  
Friction Angle ◽  
Matric Suction ◽  
Intermediate Principal Stress ◽  
Active Earth Pressure ◽  
Soil Pressure

Based on the unified solution of shear strength in terms of double stress state variables for unsaturated soils, whilst considering the effect of the intermediate principal stress rationally, the unified solution of Coulomb’s active earth pressure for unsaturated soils without cracks is developed. Comparability of the solution is analyzed and influencing characteristic of each factor is obtained. The research result indicates that: the intermediate principal stress and matric suction have obvious impacts on Coulomb’s active earth pressure for unsaturated soils; Coulomb’s active earth pressure has been decreasing until zero with the increase of unified strength theory parameter and matric suction; Coulomb’s active earth pressure increases with the increase of grading angle of retaining wall and slop angle of backfill, but decreases with the increase of matric suction, effective internal friction angle and matric suction angle, while external friction angle has no obvious influence. The proposed unified solution of Coulomb’s active earth pressure enjoys a wider application, and unified solution of Rankine’s active earth pressure is just the special case. The results are of great significance to soil pressure determination such as slope and foundation pit, and to retaining structures design.

Influence of Intermediate Principal Stress Effect on Flat Punch Problems

2013 ◽  
Vol 535-536 ◽  
pp. 300-305
Author(s):  
Zong Yuan Ma ◽  
Hong Jian Liao ◽  
Fa Ning Dang
Keyword(s):  
Principal Stress ◽  
Three Dimensional ◽  
Intermediate Principal Stress ◽  
Stress Effect ◽  
Strength Theory ◽  
Lagrangian Analysis ◽  
Flat Punch ◽  
Unified Strength Theory ◽  
Intermediate Principal Stress Effect ◽  
Punch Problem

Using the finite difference code FLAC3D (Fast Lagrangian Analysis of Continua in 3 Dimensions) and UST (Unified Strength Theory), the influence of the intermediate principal stress effect on the problems of flat punch are analyzed in this paper. The values of the ultimate bearing capacity resulting from numerical analyses and the analytical solution of Prandtl’s strip punch problem are compared. The three-dimensional problems of strip, rectangular, square and circular punches on a semi infinite metallic medium have been analyzed.

Elastoplastic Analysis of Surrounding Rocks of the Pressure Tunnel

2013 ◽  
Vol 353-356 ◽  
pp. 1644-1647
Author(s):  
Shen Qiong
Keyword(s):  
Plastic Zone ◽  
Mechanical Behavior ◽  
Principal Stress ◽  
Yield Criterion ◽  
Intermediate Principal Stress ◽  
Hydraulic Pressure ◽  
Stress Effect ◽  
Pressure Tunnel ◽  
Effect Parameter ◽  
Intermediate Principal Stress Effect

According to the triple shear unified yield criterion, the mechanical behavior of the pressure tunnel was put forward. The calculation formulas of the radius of plastic zone were deduced with considerations of the effects of the intermediate principal stress. The results show that the intermediate principal stress effect parameter b has influences on the radius of plastic zone. With the increase of the intermediate principal stress effect parameter b, the radius of plastic zone decreases. The radius of plastic zone is increased, because of the increase of the porous hydraulic pressure.

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