The problem of slope stability is considered as a main geotechnical problem due to the
significant damage (material or moral) related to failure. This paper aims to study the
influence of piles on the stability of slopes loaded with strip footing a
nd investigating the
parameters affected on stability (location of pile row relative to the slope crest X , piles
spacing S , piles length L and edge distance of the footing b ). This study has been realized
in two phases : the first phase consists in establishing a numerical model for sand slope by
using finite element analyses program (FLAC3D) and determining the footing settlement at
crest of slope before using piles and after reinforcing , after that the numerical results is
compared with the experimental ones (reference case ). A close agreement between
experimental and numerical curves is noticed .The second phase deals with studying the
influence of most important parameters such as ( piles length ,piles spacing, pile row
location relative to the slope crest on stability and edge distance of the footing) on the
slope stability. The results of parametric study have shown the piles installed near the slope
crest is more efficient in reinforcing where the safety factor is increased by reducing the
distance between row of piles and slope crest and the greatest value for safety factor when
X=0.7Lx . The currently study showed the efficiency of piles to increase the ultimate
bearing capacity with increasing edge, after that at b=3B the increase in ultimate bearing
capacity decreased. Also the slope stability depends significantly on pile length and it
increases even reaching the length equals the height of the slope. At other hand, the safety
factor is reduced by increasing the piles spacing, so that the efficiency of pile is
disappeared when pile spacing equals to six times pile diameter(UBCR<1.1).
The study was conducted on winter date (15th of Febraury), during 2015 and
2016 seasons, to study the effect of spraying calcium chloride CaCl2
concentrations (2, 4, and 6%), on the manufacture traits assigned in randomized
completely block design (RCBD) with four replicates.
This study concentrate on the driven pile in sand soils, to study and inspect this
type of piles via minimized laboratory models in conditions similar to
field conditions, and compare research result with actual load tests.
This research deals with the study of the behavior of piles under the influence of seismic loads through (3D) modeling using FE-Method-program (ABAQUS) with special reference to the most important parameters affecting the displacements and internal f
orces generated in piles. This study has been completed in two phases: the first phase is a case study of the single Pile (reference case), where a study of the behavior of a single pile assigning structure is modeled with a degree of freedom. The parametric study results show that the presence of structure causes the application of a large load in the upper part of the pile resulting from the impact of inertia dominating the kinetic effect. The forces of inertia increases with the increasing mass of structure, and when the frequency of structure nears the frequency of seismic load. The second phase deals with the study of the situation of the group of piles, where the study handles the effect of a number of piles, piles spacing, and locations on the internal force and displacements generated in the piles. The parametric study results have shown for this phase of this research that an increase the number of piles in the group causes a significant increase of internal forces generated at the top of the pile and a slight decrease for those forces in the central part of the pile, that seismic loads are not distributed equally for all piles, and that corner piles are subject to greater loads while mid. Piles are subject to less load.
A parametric study of pile load test requires a numerical modeling of this test and a study of the effect of each parameter of the material model used on pile load settlement curve shape and on the extrapolated value of pile ultimate bearing capacity
. Some real pile load tests are numerically modeled and calibrated using two types of material models: Mohr-coulomb MC and Hardening soil HS. The obtained results from HS are better than those obtained from MC, so material model HS is adopted to generate pile load settlement curves. It is shown that the relation between the extrapolated value of pile ultimate bearing capacity and each parameter of the material model used is linear, and there is only one value for each parameter of HS in which the calculated value of bearing capacity identifies with the normal value in DIN-Code. The main economic benefit obtained from this research is the ability of generating pile load settlement curves in addition to doing a parametric study using a numerical modeling method without any need to do pile load field tests. The practical scientific aim is to accumulate and collect information that can be used as a database for static pile load tests.
This research represents a trial to establish a primary database of load tests applied on concrete driven piles embedded in sandy soils. This research depended on analyzing and evaluating a large number of available load test curves of driven piles.
The variation of pile ultimate bearing capacity value is studied according to several parameters such as (relative density of sand, embedded length of pile and pile diameter). Depending on the obtained results a primary approximate relationship is suggested to calculate the ultimate bearing capacity of driven piles in sand. Then, a comparison is made between the suggested method and the other analytical calculation methods and also, with the obtained results from an available international codes of practice in America, Russia and Germany. The approximate relationship introduces a simple and easy method to calculate the bearing capacity of concrete driven piles in sands. Also, This suggested method may be considered as an introduction to developing the
researches to include different kinds of soils.
