scholarly journals Bearing Capacity Factor of Circular Footings on Two-layered Clay Soils

2021 ◽  
Vol 7 (5) ◽  
pp. 775-785
Author(s):  
Samir Benmoussa ◽  
Sadok Benmebarek ◽  
Naima Benmebarek
Keyword(s):  
Bearing Capacity ◽  
Layer Thickness ◽  
Soil Surface ◽  
Linear Increase ◽  
Layered Clays ◽  
Calculation Results ◽  
Vertical Bearing ◽  
Rigid Footing ◽  
Layered Clay ◽  
Circular Footing

Geotechnical engineers often deal with layered foundation soils. In this case, the soil bearing capacity assessment using the conventional bearing capacity theory based on the upper layer properties introduces significant inaccuracies if the top layer thickness is comparable to the rigid footing width placed on the soil surface. Under undrained conditions the cohesion increases almost linearly with depth. A few theoretical studies have been proposed in the literature in order to incorporate the cohesion variation with depth in the computation of the ultimate bearing capacity of the strip and circular footings. Rigorous solutions to the problem of circular footings resting on layered clays with linear increase of cohesion do not appear to exist. In this paper, numerical computations using FLAC code are carried out to assess the vertical bearing capacity beneath rough rigid circular footing resting on two-layered clays of both homogeneous and linearly increasing shear strength profiles. The bearing capacity calculation results which depend on the top layer thickness, the two-layered clays strength ratio and the cohesion increase rates with depth are presented in both tables and graphs, and compared with previously published results available in the literature. The critical depth for circular footing is found significantly less than for strip footing. Doi: 10.28991/cej-2021-03091689 Full Text: PDF

scholarly journals Calculation of Ultimate Bearing Capacity of Pile Foundations of Highway Bridges under the Coupling of Steep Slope and Karst

2020 ◽  
Vol 198 ◽  
pp. 02017
Author(s):  
Zhongju Feng ◽  
Shaofen Bai ◽  
Wu Min ◽  
Jingbin He ◽  
Zhouyi Huang ◽  
...  
Keyword(s):  
Bearing Capacity ◽  
Pile Foundation ◽  
Highway Bridges ◽  
Ultimate Bearing Capacity ◽  
Steep Slope ◽  
Karst Area ◽  
Correction Coefficient ◽  
Finite Element Software ◽  
Calculation Results ◽  
Vertical Bearing

In order to study the influence of steep slope-karst coupling on the vertical bearing characteristics of pile foundation, the orthogonal simulation tests of pile foundation under 4 different roof thickness and 5 different slope are carried out by using Marc finite element software, and the correction coefficient of vertical partial bearing capacity of pile foundation according to roof thickness and slope is put forward. The test results show that when the thickness of the roof is more than 3 times the pile diameter, the ultimate bearing capacity of the pile foundation tends to be stable, and the value is about 19% when the slope is 45°; the ultimate bearing capacity of the pile foundation decreases gradually with the increase of the slope, and the reduction reaches 29.83% when the slope is greater than 45°. According to the calculation results, the variation law of vertical partial bearing capacity of pile foundation is analyzed, and the calculation formula of standard value of vertical ultimate bearing capacity of pile foundation in steep slope karst area considering both roof thickness and slope is put forward, and the correction coefficients αi and β are put forward.

Study on Vertical Bearing Capacity of the Riser Composite Pile in Clay

2018 ◽  
Author(s):  
Liang Chao ◽  
Liu Run ◽  
Wan Jun ◽  
Guan Pei ◽  
Li Xiangyun
Keyword(s):  
Bearing Capacity ◽  
Cross Section ◽  
Variable Cross Section ◽  
Small Scale ◽  
Variable Cross ◽  
Pile Diameter ◽  
Composite Pile ◽  
Calculation Results ◽  
S Curve ◽  
Vertical Bearing

In order to meet the development need of small-scale marginal oilfield, it is proposed to use the riser and surface casing to bear the loads replacing or partially replacing the steel pipe pile foundation. In this paper, the vertical bearing behavior of variable cross-section composite pile with the diameter of upper part larger than that of lower part (composed of riser and surface casing) is analyzed by finite element method. Then, the influences of different length combinations and diameter combinations of the composite pile on vertical bearing mechanism are studied, and the characteristics of stress concentration at the variable cross-section are revealed. The calculation results show that the increase in pile diameter, pile length and diameter ratio can effectively improve the bearing capacity of riser composite piles. The vertical ultimate bearing capacity of riser composite piles is greatly affected by upper part and less affected by lower part. The bearing capacity of lower part is gradually exerted, as the plastic zone appears at the end of the upper part, meanwhile, the Q-s curve shows as a broken line, which means that a larger pile top settlement is needed in order to effectively activate the bearing capacity of lower part.

Behaviour of flexible piles in layered clays under eccentric and inclined loads

1995 ◽  
Vol 32 (3) ◽  
pp. 387-396 ◽  
Author(s):  
V.V.R.N. Sastry ◽  
G.G. Meyerhof
Keyword(s):  
Bearing Capacity ◽  
Soft Clay ◽  
Ground Surface ◽  
Embedment Depth ◽  
Layered Clays ◽  
Inclined Loads ◽  
Clay System ◽  
Load Tests ◽  
Layered Clay ◽  
Test Pile

The lateral soil pressures, bending moments, pile displacements at the ground surface, and the bearing capacity of instrumented vertical single flexible model piles in a layered clay system consisting of medium clay overlying soft clay under vertical eccentric and central inclined loads have been investigated. The results of these load tests are compared with theoretical estimates based on the concept of the effective embedment depth of equivalent rigid piles for ultimate and elastic cases. Reasonable agreement has been found between the observed and predicted behaviour of flexible piles. The analyses are also compared with the results of some field case records. Key words : bearing capacity, clay, instrumentation, model test, pile.

Enhancing the Bearing Capacity of Rigid Footing Using Limited Life Kenaf Geotextile Reinforcement

2020 ◽  
pp. 1-17
Author(s):  
Mohammad Gharehzadeh Shirazi ◽  
Ahmad Safuan A Rashid ◽  
Ramli Nazir ◽  
Azrin Hani Abdul Rashid ◽  
Suksun Horpibulsuk
Keyword(s):  
Bearing Capacity ◽  
Limited Life ◽  
Rigid Footing

Undrained bearing capacity of ring foundations on two-layered clays

2016 ◽  
Vol 119 ◽  
pp. 47-57 ◽  
Author(s):  
Joon Kyu Lee ◽  
Sangseom Jeong ◽  
Julie Q. Shang
Keyword(s):  
Bearing Capacity ◽  
Layered Clays ◽  
Ring Foundations

scholarly journals Improvement ratio and behavior of bearing capacity factors for strip skirt footing model resting on sand of different grain size distribution

2018 ◽  
Vol 162 ◽  
pp. 01026
Author(s):  
Mahmood Rashid Mahmood
Keyword(s):  
Grain Size ◽  
Bearing Capacity ◽  
Size Distribution ◽  
Grain Size Distribution ◽  
Coarse Sand ◽  
Linear Increase ◽  
Angle Of Internal Friction ◽  
Theoretical Approaches ◽  
Different Grain Size ◽  
Improvement Ratio

Plain strain model tests were performed on beds of sands with different particle size distribution (Coarse, Medium and Fine) prepared at loose state (Relative density Dr. of 30%). A strip footing model with skirt was placed on the bed of sand and loaded vertically up to failure at different ratios of skirt depth to width D/B of (0.5, 1.0, 1.5, 2, and 3). The applied stress increments and the corresponding settlements were measured. The improvement ratio due to different skirt depth and the behavior of bearing capacity parameters Nγ and Nq at each depth were evaluated and compared with some theoretical approaches. The test results revealed that the improvement ratio increased linearly up to D/B of 1.5 then reduced. Two factors were introduce into the general bearing capacity equation where used to evaluate bearing capacity of skirt footing, there values are about 1.6 for skirt ratio ranged between 0.5 to 1.5, and 1.25 for skirt ratio more than 1.5. Also, it is found that the Nγ parameter for D/B=0 were very close to Vesic proposal for fine and medium grain size distribution, while it’s close to Biarez proposal for coarse sand. The behavior of Nq parameter with different skirt ratio shows slight increase up to D/B of 1.5 then decrease with increasing D/B ratio for different grain size distribution. While the behavior of theoretical Nq parameter (depending on angle of internal friction values) shows a linear increase with skirt ratio for different grain size distribution.

Finite Element Simulation Analysis on Space KX-Joint

2014 ◽  
Vol 915-916 ◽  
pp. 146-149
Author(s):  
Yong Sheng Wang ◽  
Li Hua Wu
Keyword(s):  
Finite Element ◽  
Bearing Capacity ◽  
Simulation Analysis ◽  
Local Buckling ◽  
Element Model ◽  
Ansys Software ◽  
Element Simulation ◽  
Calculation Results ◽  
Buckling Failure ◽  
The Finite Element Model

The finite element model of the space KX-Joint was established using ANSYS software, and the failure mode and ultimate bearing capacity of KX-joint were researched. Calculation results show that the surface of chord wall on the roots of compression web members was into the plastic in K plane, and the holding pole without the plastic area and the local buckling failure happened in the surface of chord wall on the roots of Compression Web Members in X plane; The bearing capacity of the joint increased with the Chord diameter, which was appears in the form of power function.

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