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Foundation analysis and design
01 Jan 1968-
TL;DR: In this paper, Fondation de soutenagement et al. presented a reference record for Dimensionnement Reference Record created on 2004-09-07, modified on 2016-08-08.
Abstract: Keywords: Fondation ; Mur de soutenement ; Pieux ; Capacite portante ; Ancrage ; Dimensionnement Reference Record created on 2004-09-07, modified on 2016-08-08
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TL;DR: In this paper, a variable-head permeability test using the central portion of the velocity graph is proposed to estimate both the piezometric level (PL) and the hydraulic conductivity (k) of a monitoring well.
Abstract: A permeability test in a monitoring well (MW) is used to assess the hydraulic conductivity, k, of clay. To interpret the test data, the piezometric level (PL) during the test must be known. A previous paper has concluded that due to a long time lag, the water level in the pipe is never a PL and any extrapolation of water level versus time gives an unreliable prediction of the PL. As a result, an incorrect PL yields an incorrect k value. This paper shows that a variable-head permeability test can provide a fair estimate of both the PL and the k value when it is interpreted using the central portion of the velocity graph. The first portion of the graph, when the head difference and the gradients are high, is curved by the expansion of the injection zone (undrained and drained wall displacement with eventually some creep), and thus cannot be used. The last portion of the graph primarily reflects, with some time lag, the natural variations of hydraulic heads in adjacent aquifers, and thus must not be used.
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TL;DR: In this article, the relationship between the results of these two tests in clayey soils with low and high plasticity characteristics, a total of 20 boreholes with 1.5-4.5m depths were drilled, and both tests were performed at varying depths.
Abstract: The pressuremeter test is one of the borehole loading tests that determines the deformation characteristics of subsurface soil. The main idea of the pressuremeter test is to inflate the cylindrical hole drilled in order to measure the pressure-deformation relations of the soil. Another in situ test by which soil properties are determined is the well-known standard penetration test (SPT). The consistency and firmness of soils can be determined using the test results of these in situ tests. In order to determine the relationship between the results of these two tests in clayey soils with low and high plasticity characteristics, a total of 20 boreholes with 1.5–4.5 m depths were drilled, and both tests were performed at varying depths. Following the pressuremeter test, pure limit pressure (P
L) values and pressuremeter deformation modulus (E
M) were calculated for 31 different levels, respectively. These values were compared to SPT (N
60) values, and high determination coefficients (R
2) were attained. Therefore, for clayey soils, it is possible to determine E
M and P
L values from SPT results, and consequently SPT test results can be used to calculate settlement and bearing capacity as well as the undrained shear strength values (c
u) of low and high plasticity clayey soils.
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Cites methods from "Foundation analysis and design"
...After recording the number of blows that penetrate the tube into the ground as SPT-N30 value, an N60 value is calculated by revising it in accordance with the specifications in the literature (Bowles 1997; ASTM D1586 1999; Aggour and Radding 2001; British Standards Institution 2007; Sivrikaya and Togrol 2007)....
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...…the number of blows that penetrate the tube into the ground as SPT-N30 value, an N60 value is calculated by revising it in accordance with the specifications in the literature (Bowles 1997; ASTM D1586 1999; Aggour and Radding 2001; British Standards Institution 2007; Sivrikaya and Togrol 2007)....
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TL;DR: In this article, an experimental program in the laboratory has been conducted to study the behavior of piled raft foundation system in sandy soil under vertical load, and the influence of raft-soil stiffness and the number of piles underneath the raft on the load improvement ratio and settlement reduction ratio are presented and discussed.
Abstract: In order to study the behaviour of piled raft foundation system in sandy soil under vertical load, an experimental program in the laboratory has been conducted. The experimental program includes the model test on unpiled raft, raft supported by single pile, (2 × 2) and (3 × 3) pile groups. The piles used in this test are non-displacement piles. In the laboratory test, model mild steel piles of diameter 20 mm and a length of 200 mm were used, to represent the slenderness ratio, L/D of 10. The raft was made of mild steel plate with plan dimensions of 200 mm × 200 mm with different thicknesses of 5, 10 and 15 mm. The values of raft-soil stiffness of model rafts ranging from 0.37 to 10.11 covers flexible to very stiff raft. The refinement in the bearing capacity is represented by load improvement ratio and the reduction in average settlement is represented by settlement reduction ratio. The influence of raft-soil stiffness and the number of piles underneath the raft on the load improvement ratio and settlement reduction ratio are presented and discussed. The results of the tests show that as the number of piles underneath the raft increases from 1 to 9 piles, the load improvement ratio increases by 30–40 %, settlement reduction ratio increases by 18–90 % and percentage of load carried by the raft decreases by 22–25 %. Also load improvement ratio is slightly increases by 1.5–5 % and the settlement reduction ratio decreases by 1.5–30 % as the raft-soil stiffness ratio increases for the given number of piles, while the load carried by the raft slightly decreases by 1.5–4.5 % as the raft-soil stiffness increases.
12 citations
TL;DR: In this article, the bearing capacity of a dense sand layer overlying loose sand beneath a rigid beam is studied under the plain-strain condition using digital particle image velocimetry (DPIV) and finite element method (FEM).
12 citations