COMPUTATION OF BEARING CAPACITY FACTOR Nq –TERZAGHI AND PRANDTL MECHANISM

The unique values of the bearing capacity factors, Nq are obtained in respect of failure mechanisms suggested by Terzaghi and Prandtl using limit equilibrium approach. In this paper an attempt has been made to present the analysis integrating the Kotter’s equation with Terzaghi’s and Prandtl’s mechanisms using limit equilibrium conditions. The analysis presented here with some modifications in the exiting analyses computes the bearing capacity factor – Nq , the expressions of which are similar to the one given by Terzaghi [10] and Reissner [7] who had extended the pioneering work initiated by Prandtl [6]. The analysis reported here successfully demonstrates the applicability of Kotter’s equation to the solution of limit equilibrium problems involving plane or curved failure surfaces.

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Analytical evaluation of the effect of failure mechanisms on the bearing capacity factor Nγ for smooth strip footings

Geomechanics and Geoengineering ◽

10.1080/17486025.2021.1975049 ◽

2021 ◽

pp. 1-26

Author(s):

Alireza Najma ◽

Jitendra Sharma

Keyword(s):

Bearing Capacity ◽

Failure Mechanisms ◽

Capacity Factor ◽

Analytical Evaluation ◽

Strip Footings ◽

Bearing Capacity Factor

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A numerical study of the bearing capacity factor Nγ

Canadian Geotechnical Journal ◽

10.1139/t01-023 ◽

2001 ◽

Vol 38 (5) ◽

pp. 1090-1096 ◽

Cited By ~ 27

Author(s):

D Y Zhu ◽

C F Lee ◽

H D Jiang

Keyword(s):

Bearing Capacity ◽

Numerical Solutions ◽

Numerical Study ◽

Limit Equilibrium ◽

Failure Surface ◽

Shallow Foundation ◽

Capacity Factor ◽

Foundation Engineering ◽

Base Angle ◽

Bearing Capacity Factor

Values of the bearing capacity factor Nγ are numerically computed using the method of triangular slices. Three assumptions of the value of ψ, the base angle of the active wedge, are analyzed, corresponding to the following three cases: (1) ψ = ϕ, the internal friction angle; (2) ψ = 45° + ϕ/2; and (3) ψ has a value such that Nγ is a minimum. The location of the critical failure surface is presented and the numerical solutions to Nγ for the three cases are approximated by simple equations. The influence of the base angle on the value of Nγ is investigated. Comparisons of the present solutions are made with those commonly used in foundation engineering practice.Key words: shallow foundation, bearing capacity, bearing capacity factor, limit equilibrium.

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Determining the bearing capacity factor due to nonlinear matric suction distribution in the soil

Canadian Journal of Soil Science ◽

10.1139/cjss-2019-0071 ◽

2019 ◽

Vol 99 (4) ◽

pp. 434-446

Author(s):

Hasan Ghasemzadeh ◽

Fereshteh Akbari

Keyword(s):

Bearing Capacity ◽

Limit Equilibrium ◽

Theoretical Data ◽

Matric Suction ◽

Capacity Factor ◽

Simple Method ◽

Proposed Model ◽

Wide Range ◽

Predicted Values ◽

Bearing Capacity Factor

Bearing capacity is often calculated in dry or saturated conditions, leading to overconservative designs, for a wide range of climates in the world. Extensive researches show that bearing capacity is significantly affected by the soil matric suction. However, in most of the presented models, uniform (and sometimes linear) suction distributions are taken into account for computing the bearing capacity. Also, there is no exact solution in the residual zone of unsaturation. In the present study, a simple method is proposed to predict the bearing capacity of footings placed on unsaturated soil, using the limit equilibrium concept. Linear and uniform variations of matric suction are considered in computations, as well as the nonlinear suction distribution. The framework of the proposed model is analogous to Terzaghi’s equation, and a novel factor is developed, during calculations, as the suction bearing capacity factor. In the case of full saturation, the proposed model is simplified to the Terzaghi’s equation. Estimated results are compared with the experimental and theoretical data available in the literature. Predicted values are in a good agreement with the measured data in the transition zone and residual zone of unsaturation.

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Seismic Bearing Capacity Factor Considering Composite Failure Mechanism

International Journal of Geotechnical Earthquake Engineering ◽

10.4018/ijgee.2018010104 ◽

2018 ◽

Vol 9 (1) ◽

pp. 65-77

Author(s):

Swetha S Kurup ◽

Sreevalsa Kolathayar

Keyword(s):

Bearing Capacity ◽

Failure Mechanism ◽

Static Analysis ◽

Limit Equilibrium ◽

Failure Surface ◽

Shallow Foundation ◽

Capacity Factor ◽

Composite Failure ◽

Seismic Bearing Capacity ◽

Bearing Capacity Factor

This article describes how the design of shallow foundation needs complete knowledge about bearing capacity. During earthquakes additional lateral force acts at the foundation bed which reduces the bearing capacity. Most of the literature present either the pseudo static analysis or assume a planar failure surface to estimate seismic bearing capacity factors. Here, a pseudo dynamic approach that considers the time dependent effect of earthquake loading is employed. A composite failure surface has been considered for a more realistic estimation of seismic bearing capacity. New expressions were formulated to arrive at the seismic bearing capacity factor, considering the forces acting on the failure wedge based on the limit equilibrium approach. The effect of soil friction angles and the seismic peak of horizontal ground accelerations on the seismic bearing capacity were studied using the proposed method. It was observed that present pseudo-dynamic analysis with a composite failure mechanism gives lower values of seismic bearing capacity factors when compared to pseud- static analysis.

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