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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: The findings relatively support the usage of stabilizers or byproducts in the production of geopolymers for potential use in deep mixing and could be a basis for further efforts in this area.
Abstract: This research aims to experimentally investigate the potential use of a geopolymer made from various stabilizers or byproducts (fly ash (FA-F, FA-C), slag (SL), glass powder (GP), metakaolin (MK), marble powder (MP), bottom ash (BA), rice husk ash (RHA), silica fume (SF)) to enhance the mechanical performance of soil (clay) via a deep mixing technique. Strengths of geopolymer soilcrete specimens were determined by unconfined compressive strength (UCS) tests regarding curing times (7 to 365 days) by comparing with Portland cement (PC). In addition, ultrasonic pulse velocity (UPV) tests, the effect of molarity (8–16 M), stress-strain behavior, failure modes, and microstructure (SEM, EDX) of geopolymer specimens were examined. Compared to PC, UCS responses of geopolymer specimens yielded: (i) a decreasing trend for FA-F, GP, MK, BA, and MP + FA-F, (ii) an increasing trend for FA-C, SL, and combinations of SL (BA + SL, RHA + SL, SF + SL, MK + SL) favorable with fewer proportions of stabilizers, and (iii) higher increments due to long-term curing (90, 365 days). Despite some decrements, most UCS values were found acceptable (>0.2 MPa) for sufficient enhancement of soft clay. The UCS results were mostly confirmed by UPV performances. The geopolymer specimens were also found to present: (i) strength development for alkaline concentrations from 10 to 14 M, (ii) brittle behavior of stress–strain curves that failed in axial splitting and near axial directions, and (iii) intensity of the silica peak for strength responsibility of the dense microstructure. The findings relatively support the usage of stabilizers or byproducts in the production of geopolymers for potential use in deep mixing. Thus, this research could be a basis for further efforts in this area.
43 citations
TL;DR: In this article, the p-y curve is constructed from experimentally obtained stress-strain relationship of the soil by using the Mobilized Strength Design (MSD) concept.
Abstract: In practice, analysis of laterally loaded piles is carried out using beams on non-linear Winkler springs model (often known as p-y method) due to its simplicity, low computational cost and the ability to model layered soils. In this approach, soil-pile interaction along the depth is characterized by a set of discrete non-linear springs represented by p-y curves where p is the pressure on the soil that causes a relative deformation of y. p-y curves are usually constructed based on semi-empirical correlations. In order to construct API/DNV proposed p-y curve for clay, one needs two values from the monotonic stress-strain test results i.e., undrained strength (su) and the strain at 50% yield stress (e50). This approach may ignore various features for a particular soil which may lead to un-conservative or over-conservative design as not all the data points in the stress-strain relation are used. However, with the increasing ability to simulate soil-structure interaction problems using highly developed computers, the trend has shifted towards a more theoretically sound basis. In this paper, principles of Mobilized Strength Design (MSD) concept is used to construct a continuous p-y curves from experimentally obtained stress-strain relationship of the soil. In the method, the stress-strain graph is scaled by two coefficient NC(for stress) and MC(for strain) to obtain the p-y curves. MC and NC are derived based on Semi-Analytical Finite Element approach exploiting the axial symmetry where a pile is modelled as a series of embedded discs. An example is considered to show the application of the methodology.
43 citations
TL;DR: In this article, the tensile force in a reinforced bridge abutment is calculated for cylinders reinforced with geotextiles at 6-in. (152mm) vertical spacing.
Abstract: Bridge abutments made of geotextile-reinforced soil have been shown to support the bridge load without the use of piles. However, current design procedures are considered to be conservative. To determine the strength, and to understand better the behavior of reinforced soil, large unconfined cylindrical soil samples reinforced with geosynthetics were axisymmetrically loaded. Samples were 2.5 ft (0.76 m) in diameter and 5 ft (1.52 m) in height. Peak strengths of 4.8 kips/ft2 (230 kPa) to 9.6 kips/ft2 (460 kPa) at 3% to 8.5% vertical strain were obtained from cylinders reinforced with geotextiles at 6-in. (152-mm) vertical spacing. A strength reduction occurred after the peak strength, but most of the loads were sustained up to at least 10% strain before yielding. Tension in the reinforcement appears to be mobilized first in the middle layers, as determined from the location of tears in the geotextile. An equation to calculate the tensile force in the reinforcement, Tmax, in a reinforced bridge abutment is ...
43 citations
Cites methods from "Foundation analysis and design"
...The Jaky equation for Ko (Bowles, 1988) was used where: K 1 - sin <I> (1 2....
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01 Nov 1997
TL;DR: In this paper, a user friendly microcomputer data base of spread footings, case histories and load tests was used to evaluate the performance of five large scale square footings in sand.
Abstract: Spread footings are most often less expensive than deep foundations. In an effort to improve the reliability of spread footings, this research project was undertaken. The results consist of: (1) a user friendly microcomputer data base of spread footings, case histories and load tests; (2) the performance of five large scale square footings in sand; (3) an evaluation of the current accuracy of settlement and bearing capacity prediction methods; (4) observations on the scale effect, the zone of influence, the creep settlement, and soil heterogeneity; (5) a new and simple method to predict the complete load settlement curve for a footing as well as several correlations; and (6) evaluation of the WAK test, a dynamic test for spread footings.
42 citations
Cites methods from "Foundation analysis and design"
...…of total unit weight, YT in (kN/mj), relative density, DR in (Oh), and angle of internal friction, O The calculations for relative density are based on a relationship derived, for saturated sands, by Gibbs and Holtz (1957) and those for unit weight are based on data published by Bowles (1988)....
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TL;DR: In this article, the authors studied the process of potential landslide damming using slope failure mechanism, dam dimension and dam stability evaluation, and found that the landslide has attained an areal increase of 103,900-±-1142-m2 during year 2004-2016.
Abstract: This work aims to understand the process of potential landslide damming using slope failure mechanism, dam dimension and dam stability evaluation. The Urni landslide, situated on the right bank of the Satluj River, Himachal Pradesh (India) is taken as the case study. The Urni landslide has evolved into a complex landslide in the last two decade (2000–2016) and has dammed the Satluj River partially since year 2013, damaging ∼200 m stretch of the National Highway (NH-05). The crown of the landslide exists at an altitude of ∼2180–2190 m above msl, close to the Urni village that has a human population of about 500. The high resolution imagery shows ∼50 m long landslide scarp and ∼100 m long transverse cracks in the detached mass that implies potential for further slope failure movement. Further analysis shows that the landslide has attained an areal increase of 103,900 ± 1142 m2 during year 2004–2016. About 86% of this areal increase occurred since year 2013. Abrupt increase in the annual mean rainfall is also observed since the year 2013. The extreme rainfall in the June, 2013; 11 June (∼100 mm) and 16 June (∼115 mm), are considered to be responsible for the slope failure in the Urni landslide that has partially dammed the river. The finite element modelling (FEM) based slope stability analysis revealed the shear strain in the order of 0.0–0.16 with 0.0–0.6 m total displacement in the detachment zone. Further, kinematic analysis indicated planar and wedge failure condition in the jointed rockmass. The debris flow runout simulation of the detached mass in the landslide showed a velocity of ∼25 m/s with a flow height of ∼15 m while it (debris flow) reaches the valley floor. Finally, it is also estimated that further slope failure may detach as much as 0.80 ± 0.32 million m3 mass that will completely dam the river to a height of 76 ± 30 m above the river bed.
42 citations