Rock Mechanics
Anant Saini; Jitendra Singh Yadav
Abstract
The goal of this research work was to use an Artificial Neural Network (ANN) model to predict the ultimate bearing capacity of circular footing resting on recycled construction waste over loose sand. A series of plate load tests were conducted by varying the thickness of two sizes of recycled construction ...
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The goal of this research work was to use an Artificial Neural Network (ANN) model to predict the ultimate bearing capacity of circular footing resting on recycled construction waste over loose sand. A series of plate load tests were conducted by varying the thickness of two sizes of recycled construction waste (5 mm and 10.6 mm) layer (0.4d, 0.6d, 0.8d, 1d, and 1.2d, d: diameter of footing) prepared at different relative densities (30%, 50%, and 70%) overlaying. The ultimate bearing capacity obtained for various combinations was used to develop the ANN model. The input parameters of the ANN model were thickness of recycled construction waste layer to diameter of circular footing ratio, angle of internal friction of sand, unit weight of sand, angle of internal friction of recycled construction waste and unit weight of recycled construction waste, and the model's output parameter was ultimate bearing capacity. The FANN-SIGMOD_SYMMETRIC model with topology 3-2-1 provided a higher estimate of the ultimate bearing capacity of circular footing, according to the ANN findings. The sensitivity analysis also revealed that the unit weight of sand and angle of internal friction of sand had insignificant effects on ultimate bearing capacity. The estimated ultimate bearing capacity was most affected by the angle of internal friction of recycled construction waste. The result of multiple linear regression analysis was not as good as the ANN model at predicting the ultimate bearing capacity.
Imran Khan; Ravi Kumar Sharma
Abstract
An experimental study is carried out to improve the bearing capacity of soils by using geotextile. In the present study geotextile (tire reinforcement) is used as geotextile, whereas sand is used as a soil medium. This research work presents the results of laboratory load tests on model square footings ...
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An experimental study is carried out to improve the bearing capacity of soils by using geotextile. In the present study geotextile (tire reinforcement) is used as geotextile, whereas sand is used as a soil medium. This research work presents the results of laboratory load tests on model square footings supported on reinforced sand beds. A total of twenty-seven load tests are conducted to evaluate the effects of single layer reinforcement placed below square model footings. The parameters of the testing program of the research work are the depth of reinforcement, the plan area of reinforcement, and the number of reinforcements. From the experimental data, it is indicated that there is an optimum reinforcement depth at which the bearing capacity is the highest. Also, the optimum size of reinforcement is found to be 1.5 B×1.5 B irrespective of the type of reinforcing materials used. The bearing capacity of reinforced sand is also found to increase with the number of reinforcement layer and reinforcement size when the reinforcement is placed within a certain effective zone with high relative density. The optimum placement position of geotextile is found to be 0.5B to 0.75B from the base of the footing .The tests are done at two different relative densities, i.e., 40% and 60%. The bulk unit weight of sandy soil is 14.81 KN/m³. Maximum gain in load carrying capacity is obtained when depth of reinforcement/width of footing (Dr/B) is 0.5 at relative density of 40% and 0.75 at a relative density of 60%.In addition, the data indicate that increasing reinforcement beyond a certain value would not bring about further increase in the bearing capacity of the soil.
Gaurav Juneja; Ravi Kumar Sharma
Abstract
This paper presents the numerical analysis of square and circular skirted footings placed on different sands using the PLAXIS 3D software. The numerical analysis is done using the Mohr-coulomb (M-C) yield criteria. The size of the footings is considered as 100 mm for both the square and circular footings. ...
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This paper presents the numerical analysis of square and circular skirted footings placed on different sands using the PLAXIS 3D software. The numerical analysis is done using the Mohr-coulomb (M-C) yield criteria. The size of the footings is considered as 100 mm for both the square and circular footings. The three different friction angles (Ø) of sand 36˚, 40˚, and 42˚ are used to study the effect of sand compactness. The depth of the skirt (h) varies from 0B to 2B (B is the width of the footing). The surface roughness between skirt-sand and footing-sand is considered partially rough and completely rough. The interface friction factor (δ) for a partially rough and fully rough interface is taken as 2/3Ø and Ø. All the tests are conducted by applying a prescribed displacement (s/B) of 20% of the footing size. The results obtained from the present work reveal that the inclusion of structural skirts with the footings appreciably increases the bearing capacity and reduces the settlement of the footing by increasing the skirt depth. The results obtained show that the skirted footing is found to be more effective in loose sand compared to dense sand in increasing the bearing capacity. The numerical analysis results are also verified with the experimental results available in the literature and multiple regression model. This work shows that the prediction of the accuracy of the results is quite good with the experimental results and the generated regression model.
S. Sepehri; R. Shirinabadi; N. Hosseini Alaee; E. Moosavi; A. H. Bangian Tabrizi
Abstract
In this research work, a 3D numerical modeling technique is proposed based on the 3D particle flow code in order to investigate the failure mechanism of rock foundations. Two series of footings with different geometries and areas are considered in this work. The failure mechanism obtained is similar ...
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In this research work, a 3D numerical modeling technique is proposed based on the 3D particle flow code in order to investigate the failure mechanism of rock foundations. Two series of footings with different geometries and areas are considered in this work. The failure mechanism obtained is similar to that of the Terzaghi’s but there is a negligible difference in between. Lastly, one equation is presented to calculate the bearing capacity based on the results achieved from the numerical model and the Mohr-Coulomb theory. The sensitivity analyses are performed on the friction angle, cohesion, and footing width. The results obtained are compared with the corresponding results given by the equations given by Terzaghi and Meyerhof. This comparison demonstrates a good agreement between them. In the friction angle sensitive analysis, the amounts of the bearing capacity diagram are very close to Meyerhof’s, which overlap with each other.
