Current Search: bearing capacity (x)
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- Title
- EFFECT OF HORIZONTAL PILES ON THE SOIL BEARING CAPACITY FOR CIRCULAR FOOTING ABOVE CAVITY.
- Creator
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Arosemena, Rafael, Kuo, Shiou-San, University of Central Florida
- Abstract / Description
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The design of foundation in normal soil conditions is governed by bearing capacity, minimum depth of foundation and settlement. However, foundation design in karst regions needs to consider an additional criterion associated to the possibility of subsurface subsidence and ravelling sinkholes. Under this environment, alternative techniques are needed to improve the subsurface soil. In this study general background information is given to understand the geological characteristics of Central...
Show moreThe design of foundation in normal soil conditions is governed by bearing capacity, minimum depth of foundation and settlement. However, foundation design in karst regions needs to consider an additional criterion associated to the possibility of subsurface subsidence and ravelling sinkholes. Under this environment, alternative techniques are needed to improve the subsurface soil. In this study general background information is given to understand the geological characteristics of Central Florida and why this area is considered to be a karst region and susceptible to sinkholes formation. Traditional foundation design techniques on karst regions are addressed in this paper. Finally, the use of a network of three subsurface horizontal piles is proposed and the effect on stress increase and soil bearing capacity for footing due to the horizontal piles is investigated. Finite element computer software is used to analyze the stress distribution under different conditions and the results are discussed. The objective of this study is to determine whether or not horizontal piles under a circular footing at the sinkhole site is a viable solution to reduce the stress increase in the soil induced by the footing load. The horizontal piles located at a certain depth below the center of the footing intercepts the cone of pressure due to the footing load. Also, it is the purpose of this research to determine the effect on the soil bearing capacity for footing due to the proposed horizontal piles at the sinkhole prone area. In 1983 Baus, R.L and Wang, M.C published a research paper on soil bearing capacity for strip footing above voids. In their research, a chart for soil bearing capacity for strip footing located above a void was presented. However, in this paper we present a chart for circular footing size as a function void location and a design chart for circular footing size with a network of three underground piles. The result indicates that with the horizontal piles placed above the cavity, the stress increase caused by the footing load substantially decreases as compared to the situation of no horizontal piles, thus increases the soil bearing capacity for the normal design of footing size. The approach of using the horizontal piles placed in between the footing and the subsurface cavity is a new concept that has not been experienced previously. The results are strictly based on the analytical model of finite element program. Before full implementation for the construction practice, further research and experimental work should be conducted.
Show less - Date Issued
- 2007
- Identifier
- CFE0001643, ucf:47224
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0001643
- Title
- NUMERICAL COMPUTATIONS FOR PDE MODELS OF ROCKET EXHAUST FLOW IN SOIL.
- Creator
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Brennan, Brian, Moore, Brian, University of Central Florida
- Abstract / Description
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We study numerical methods for solving the nonlinear porous medium and Navier-Lame problems. When coupled together, these equations model the flow of exhaust through a porous medium, soil, and the effects that the pressure has on the soil in terms of spatial displacement. For the porous medium equation we use the Crank-Nicolson time stepping method with a spectral discretization in space. Since the Navier-Lame equation is a boundary value problem, it is solved using a finite element method...
Show moreWe study numerical methods for solving the nonlinear porous medium and Navier-Lame problems. When coupled together, these equations model the flow of exhaust through a porous medium, soil, and the effects that the pressure has on the soil in terms of spatial displacement. For the porous medium equation we use the Crank-Nicolson time stepping method with a spectral discretization in space. Since the Navier-Lame equation is a boundary value problem, it is solved using a finite element method where the spatial domain is represented by a triangulation of discrete points. The two problems are coupled by using approximations of solutions to the porous medium equation to define the forcing term in the Navier-Lame equation. The spatial displacement solutions can be used to approximate the strain and stress imposed on the soil. An analysis of these physical properties shows whether or not the material ceases to act as an elastic material and instead behaves like a plastic which will tell us if the soil has failed and a crater has formed. Analytical as well as experimental tests are used to find a good balance for solving the porous medium and Navier-Lame equations both accurately and efficiently.
Show less - Date Issued
- 2010
- Identifier
- CFE0003217, ucf:48565
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0003217