Bearing Capacity of Strip Footings in Two Layered Cohesive-friction Soils

1974 ◽  
Vol 11 (1) ◽  
pp. 32-45 ◽  
Author(s):  
P. Purushothamaraj ◽  
B. K. Ramiah ◽  
K. N. Venkatakrishna Rao
Keyword(s):  
Bearing Capacity ◽  
Failure Mechanism ◽  
Friction Angle ◽  
Unit Weight ◽  
Layered Soils ◽  
Strip Footings

A method has been formulated for bearing capacity of footings on two layered soils with varying cohesion, friction, and unit weight based on the second theorem of Drucker and Prager (kinematical consideration). The failure mechanism considered was fundamentally similar to that of Prandtl–Terzaghi but with different wedge angles. The critical wedge angles were found in each case. Bearing capacity charts for footings are presented by varying cohesion in layers, with the same friction angle and unit weight. The charts are readily usable for any combination of c2/c1, d/b, φ, and γ.

Pseudo-Dynamic Bearing Capacity of Shallow Strip Footing Resting on c-Φ Soil Considering Composite Failure Surface

2015 ◽  
Vol 6 (2) ◽  
pp. 12-34 ◽  
Author(s):  
Arijit Saha ◽  
Sima Ghosh
Keyword(s):  
Bearing Capacity ◽  
Failure Mechanism ◽  
Limit Equilibrium ◽  
Failure Surface ◽  
Friction Angle ◽  
Strip Footing ◽  
Unit Weight ◽  
Composite Failure ◽  
Seismic Accelerations ◽  
Seismic Bearing Capacity

The evaluation of bearing capacity of shallow strip footing under seismic loading condition is an important phenomenon. This paper presents a pseudo-dynamic approach to evaluate the seismic bearing capacity of shallow strip footing resting on c-F soil using limit equilibrium method considering the composite failure mechanism. A single seismic bearing capacity coefficient (N?e) presents here for the simultaneous resistance of unit weight, surcharge and cohesion, which is more practical to simulate the failure mechanism. The effect of soil friction angle(F), soil cohesion(c), shear wave and primary wave velocity(Vs, Vp) and horizontal and vertical seismic accelerations(kh, kv) are taken into account to evaluate the seismic bearing capacity of foundation. The results obtained from the present analysis are presented in both tabular and graphical non-dimensional form. Results are thoroughly compared with the existing values in the literature and the significance of the present methodology for designing the shallow strip footing is discussed.

scholarly journals Bearing Capacity of Ring Foundations on Sand Overlying Clay

2020 ◽  
Vol 10 (13) ◽  
pp. 4675
Author(s):  
Chaowei Yang ◽  
Zhiren Zhu ◽  
Yao Xiao
Keyword(s):  
Bearing Capacity ◽  
Friction Angle ◽  
Failure Criteria ◽  
Unit Weight ◽  
Sand Layer ◽  
Collapse Mechanisms ◽  
Internal Radius ◽  
Vertical Bearing ◽  
Vertical Bearing Capacity ◽  
Ring Foundations

The vertical bearing capacity of rough ring foundations resting on a sand layer overlying clay soil is computed in this study by using finite element limit analysis (FELA). The sands and clays are assumed as elastoplastic models, obeying Mohr–Coulomb and Tresca failure criteria, respectively. Based on the FELA results, design charts are provided for evaluating the ultimate bearing capacity of ring foundations, which is related to the undrained shear strength of the clay, the thickness, the internal friction angle, the unit weight of the sand layer, and the ratio of the internal radius to the external radius of the footing. A certain thickness, beyond which the clay layer has a negligible effect on the bearing capacity, is determined. The collapse mechanisms are also examined and discussed.

Experimental study of punching coefficients and shape factor for two-layered soils

1979 ◽  
Vol 16 (4) ◽  
pp. 802-805 ◽  
Author(s):  
A. J. Valsangkar ◽  
G. G. Meyerhof
Keyword(s):  
Experimental Study ◽  
Bearing Capacity ◽  
Shape Factor ◽  
Model Tests ◽  
Punching Shear ◽  
Deep Foundations ◽  
Layered Soils ◽  
Shape Factors ◽  
Capacity Theory ◽  
Strip Footings

The ultimate bearing capacity of deep foundations has been investigated for the case of a strong layer overlying a weak stratum. The studies are based on model tests using buried circular and strip footings for a range of layer thicknesses. Based on the previously developed bearing capacity theory, the punching shear coefficients and corresponding shape factors have been evaluated.

Ultimate bearing capacity of foundations on layered soils under inclined load

1978 ◽  
Vol 15 (4) ◽  
pp. 565-572 ◽  
Author(s):  
G. G. Meyerhof ◽  
A. M. Hanna
Keyword(s):  
Bearing Capacity ◽  
Ultimate Bearing Capacity ◽  
Model Tests ◽  
Clay Soils ◽  
Layered Soils ◽  
Inclined Load ◽  
Soft Layer ◽  
Soil Failure ◽  
Strip Footings

The ultimate bearing capacity of footings resting on subsoils consisting of two layers has been investigated for the cases of a dense or stiff layer overlying a weak deposit, and a loose or soft layer overlying a firm deposit. The analyses of different modes of soil failure are compared with the results of model tests on circular and strip footings on layered sand and clay soils.

Upper bound to bearing capacity of layered soils

1989 ◽  
Vol 26 (4) ◽  
pp. 730-736 ◽  
Author(s):  
Antoni Florkiewicz
Keyword(s):  
Experimental Data ◽  
Bearing Capacity ◽  
Limit State ◽  
Layered Soils ◽  
Flat Punch ◽  
Layer System ◽  
Capacity Limit ◽  
Strip Footings ◽  
Kinematical Approach ◽  
Layered Half Space

An approach to the problem of flat punch indentation into the Mohr-Coulomb layered half-space has been developed, based on the kinematical approach of limit analysis. A kinematically admissible plane-strain failure mechanism for a typical two-layer system is presented. The ultimate bearing capacity for strip footings obtained from the proposed approach compares well with the experimental data available in the literature. Key words: bearing capacity, limit state analysis, layered soil, strip footings.

Study on Vertical Bearing Capacity of the Wide-Shallow Bucket Foundation in Two Layered Sand

2020 ◽  
Author(s):  
Guodong Sun ◽  
Run Liu ◽  
Jijian Lian ◽  
Runbo Cai ◽  
Xu Yang ◽  
...  
Keyword(s):  
Internal Friction ◽  
Bearing Capacity ◽  
Friction Angle ◽  
Internal Friction Angle ◽  
Unit Weight ◽  
Offshore Wind Turbine ◽  
Sand Layer ◽  
Bucket Foundation ◽  
Vertical Bearing ◽  
Vertical Bearing Capacity

Abstract The wide-shallow bucket foundation proposed by Tianjin University of China is a new type of offshore wind turbine foundation. In this paper, the vertical bearing capacity of wide-shallow bucket foundation embedded in two layered sand that contains an underlying medium strength sand layer and a weaker or stronger overlaying sand layer is studied. A parametric study for bearing capacity is carried out with the ratio of unit weight γ1/γ2 (where γ1 and γ2 are the unit weight of the upper and lower sand layers respectively), the ratio of internal friction angle φ1/φ2 (where φ1 and φ2 are the internal friction angle of the upper and lower sand layers respectively) and relative thickness of the top sand layer H1/B (where H1 and B are the thickness of the top sand layer and the bucket foundation diameter). All of the presents were performed by the Finite Element Method and the results show that the thickness of the top layer has a great influence on the vertical bearing capacity of the foundation. Specifically, the upper sand layer is stronger, the bearing capacity ascends with the increase of the thickness of the top layer, and on the contrary, the upper layer is weaker, and the bearing capacity decreases with the increase of the top layer thickness. In addition, the bearing capacity of the foundation also increases with the ratios of the effective unit weight and the internal friction angle.

Exact probabilistic solution of two-parameter bearing capacity for shallow foundations

1992 ◽  
Vol 29 (5) ◽  
pp. 867-870 ◽  
Author(s):  
Said M. Easa
Keyword(s):  
Bearing Capacity ◽  
Random Variable ◽  
Friction Angle ◽  
Shallow Foundations ◽  
Cohesionless Soil ◽  
Unit Weight ◽  
Previous Solution ◽  
Probabilistic Solution ◽  
Two Parameter ◽  
Soil Unit

An exact probabilistic solution of the ultimate bearing capacity of cohesionless soil for shallow strip foundations is presented. The solution incorporates two random variables: effective friction angle [Formula: see text] and soil unit weight γ. This solution is an extension of a previous solution in which only [Formula: see text] is considered as a random variable. The exact solution is verified using Monte Carlo simulation and the sensitivity of the solution to the coefficient of variation of the soil unit weight is examined. Key words : probability, reliability, bearing capacity, shallow strip foundations, friction angle, soil unit weight.

Effect of footing width on Nγ and failure envelope of eccentrically and obliquely loaded strip footings on sand

2015 ◽  
Vol 52 (6) ◽  
pp. 694-707 ◽  
Author(s):  
Chong Tang ◽  
Kok-Kwang Phoon ◽  
Kim-Chuan Toh
Keyword(s):  
Bearing Capacity ◽  
Friction Angle ◽  
Computational Procedure ◽  
Combined Loading ◽  
Classical Solutions ◽  
Foundation Design ◽  
Second Order Cone ◽  
Constant Friction ◽  
Variable Friction ◽  
Strip Footings

This paper thoroughly investigates the bearing capacity of strip footings on sand under combined loading by using a lower-bound limit analysis in conjunction with finite elements and second-order cone programming (SOCP). Two analyses were performed: one using a constant friction angle and the other using a variable friction angle. The analyses with a constant friction angle were used to calibrate the existing results, including the classical solutions commonly used in foundation design practice and other numerical or experimental solutions. The analyses with a variable friction angle allow us to investigate the effect of footing width B on the bearing capacity of strip footings. An iteration computational procedure is employed to account for the dependency of the friction angle on the stress level. According to the numerical results, it is found that the bearing capacity factor Nγ for eccentrically or obliquely loaded strip footings linearly decreases with the increase of B on a log–log scale, where the range 0.3–5 m of footing width was considered in this paper. In addition, it is found that the footing width has a negligible effect on the shape and size of the normalized failure envelopes.

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