Influence of random heterogeneity of the friction angle on bearing capacity factorNγ

Author(s):  
Ghazal Rezaie Soufi ◽  
Reza Jamshidi Chenari ◽  
Mehran Karimpour Fard
2021 ◽  
Vol 7 ◽  
Author(s):  
Kouseya Choudhuri ◽  
Debarghya Chakraborty

This paper intends to examine the influence of spatial variability of soil properties on the probabilistic bearing capacity of a pavement located on the crest of a fibre reinforced embankment. An anisotropic random field, in combination with the finite difference method, is used to carry out the probabilistic analyses. The cohesion and internal friction angle of the soil are assumed to be lognormally distributed. The Monte Carlo simulations are carried out to obtain the mean and coefficient of variation of the pavement bearing capacity. The mean bearing capacity of the pavement is found to decrease with the increase in horizontal scale of fluctuation for a constant vertical scale of fluctuation; whereas, the coefficient of variation of the bearing capacity increases with the increase in horizontal scale of fluctuation. However, both the mean and coefficient of variation of bearing capacity of the pavement are observed to be increasing with the increase in vertical scale of fluctuation for a constant horizontal scale of fluctuation. Apart from the different scales of fluctuation, the effects of out of the plane length of the embankment and randomness in soil properties on the probabilistic bearing capacity are also investigated in the present study.


2020 ◽  
Vol 10 (13) ◽  
pp. 4675
Author(s):  
Chaowei Yang ◽  
Zhiren Zhu ◽  
Yao Xiao

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.


2011 ◽  
Vol 48 (3) ◽  
pp. 425-438 ◽  
Author(s):  
Won Taek Oh ◽  
Sai K. Vanapalli

The bearing capacity and settlement of foundations are determined experimentally or modelled numerically based on conventional soil mechanics for saturated soils. In both methods, bearing capacity and settlement are estimated based on the applied vertical stress versus surface settlement relationship. These methods are also conventionally used for soils that are in an unsaturated condition, ignoring the contribution of matric suction. In this study, a methodology is proposed to estimate the bearing capacity and settlement of shallow foundations in unsaturated sands by predicting the applied vertical stress versus surface settlement relationship. The proposed method requires soil parameters obtained under only saturated conditions (i.e., effective cohesion, effective internal friction angle, and modulus of subgrade reaction from model footing test) along with the soil-water characteristic curve (SWCC). In addition, finite element analyses are undertaken to simulate the applied vertical stress versus surface settlement relationship for unsaturated sands. The proposed method and finite element analyses are performed using an elastic – perfectly plastic model. The predicted bearing capacities and settlements from the proposed method and finite element analyses are compared with published model footing test results. There is good agreement between measured and predicted results.


2005 ◽  
Vol 20 (4) ◽  
pp. 324-341 ◽  
Author(s):  
Radu Popescu ◽  
George Deodatis ◽  
Arash Nobahar

2018 ◽  
Vol 2 (1) ◽  
Author(s):  
Yungming Cheng

<p>In this paper, the classical bearing capacity problem and the logspiral transition zone are re-considered from a continuum plasticity approach as well as discrete element approach. In the discrete element approach, the bearing capacity problem is considered from the elastic stage, plastic stage to the final rupture stage. It is found that there are noticeable differences in the failure mechanism between the continuum and discontinuum analyses, and the well-known logspiral transition zone is also not apparent in both the discrete element approach, plasticity approach as well as the laboratory tests. With the increase in the friction angle of soil, the transition zone is becoming more like a wedge zone than a logspiral zone as found from the present study. </p>


2021 ◽  
Vol 31 (3) ◽  
pp. 152-176
Author(s):  
Priyanka Rawat ◽  
Rakesh Kumar Dutta

Abstract The aim of the present numerical study was to analyse the pressure settlement behaviour and bearing capacity of asymmetric plus shaped footing resting on loose sand overlying dense sand at varying embedment depth. The numerical investigation was carried out using ABAQUS software. The effect of depth of embedment, friction angle of upper loose and lower dense sand layer and thickness of upper loose sand on the bearing capacity of the asymmetric plus shaped footing was studied in this investigation. Further, the comparison of the results of the bearing capacity was made between the asymmetric and symmetric plus shaped footing. The results reveal that with increase in depth of embedment, the dimensionless bearing capacity of the footings increased. The highest increase in the dimensionless bearing capacity was observed at embedment ratio of 1.5. The increase in the bearing capacity was 12.62 and 11.40 times with respect to the surface footings F1 and F2 corresponding to a thickness ratio of 1.5. The lowest increase in the dimensionless bearing capacity was observed at embedment ratio of 0.1 and the corresponding increase in the bearing capacity was 1.05 and 1.02 times with respect to the surface footing for footings F1 and F2 at a thickness ratio of 1.5.


Author(s):  
Guodong Sun ◽  
Run Liu ◽  
Jijian Lian ◽  
Runbo Cai ◽  
Xu Yang ◽  
...  

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.


Author(s):  
Tim Pucker ◽  
Britta Bienen ◽  
Sascha Henke

Prediction of the bearing behavior of vertical loaded shallow foundations is typically done using the classical bearing capacity approach. This approach is very sensitive to the friction angle assumed in the calculation. A conservative estimate of the bearing capacity is required for most applications, hence uncertainties in the friction angle may be absorbed by the safety factor applied. Spudcans are used to found mobile jack-up platforms in the oil and gas industry as well as in the offshore wind energy industry. Contrary to the classical approach, the bearing capacity of spudcans has to be predicted accurately. Spudcans are penetrated into the seabed and a continuous bearing failure proceeds until the target capacity is met. A Coupled Eulerian-Lagrangian (CEL) approach is used to simulate the penetration process of spudcans into silica sand. The sand is modeled using a hypoplastic constitutive model to capture the influence of the void ratio and stress state for example. A parametric study of foundation diameter and enclosed cone angle is presented. The numerical model is validated against results from centrifuge experiments of flat and conical circular footings penetrating into silica sand. A first empirical approach to estimate the bearing capacity depending on the diameter and enclosed cone angle is given for silica sand.


2014 ◽  
Vol 580-583 ◽  
pp. 3003-3006
Author(s):  
Qian Qian Sun ◽  
Tai Quan Zhou ◽  
Xiao Jie Gu

Limit bearing capacity of foundation soil was studied in the paper using slip line method. Slip line results are found to be consistent with the results calculated by Terzaghi theoretical formula and Hansen theoretical formula. Then the influence of factors such as cohesion and friction angle is studied under complete smooth or complete tough conditions. The results show that in a certain range, limit bearing capacity of foundation increases with the increase of C0, Φ. Limit bearing capacity of foundation under complete smooth condition is lower than the complete tough one.


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