Investigation of factors influencing behavior of single geocell-reinforced bases under static loading
ABSTRACT Geocell, one type of geosynthetics manufactured in the form of three-dimensional interconnected cells, can be used as a reinforcement to improve the behavior of base courses by providing lateral confinement to increase their stiffness and strength and reduce surface permanent-deformation. However, the use of geocells for base reinforcement is hindered by the existing gap between applications and theories. This study experimentally investigated the factors influencing the behavior (stiffness and bearing capacity) of single geocell-reinforced bases including shape, type, embedment, height of geocells, and quality of infill materials. Three of the four types of geocells investigated in this study were made of novel polymeric alloys using a new manufacturing technology. Repeatability and potential scale effects on test results were examined. The test results showed that the geocell placed in a circular shape had a higher stiffness and bearing capacity than that placed in an elliptical shape. The performance of the geocell-reinforced base depended on the elastic modulus of the geocell sheet. The unconfined geocell had a lower stiffness but a higher ultimate load capacity than the confined geocell. The benefit of the geocell was minimized when the infill material, quarry waste with apparent cohesion, was used as compared with the Kansas River sand without apparent cohesion. The single geocell-reinforced base had a lower stiffness and bearing capacity than the multiple geocell-reinforced base.
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ABSTRACT: Supported palladium catalysts prepared from palladium(II) acetate and SBA-15 type molecular sieve modified with N-[2-(diethylamino)ethyl]-3-aminopropyl donor groups efficiently catalyse reductive dehalogenation of various bromo- and iodobenzenes with in situ formed triethylammonium formate as the hydrogen source. Since the corresponding chlorobenzenes react at considerably lower rates while fluorobenzenes remain unaffected, the catalytic system can be utilised for selective dehalogenations of multiply halogenated substrates. Compared with Pd/C tested earlier [N.A. Cortese, R.F. Heck, J. Org. Chem. 42 (1977) 3491], the catalysts deposited over modified SBA-15 are more reactive. Besides, they exert rather minor leaching of the metal component (8.4% during five consecutive runs with 0.5mol.% Pd with respect to the substrate) and maintain their high activity during repeated use.Journal of Molecular Catalysis A Chemical 05/2011; 341(1):97-102. · 3.19 Impact Factor
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ABSTRACT: The study presented in this paper aimed to investigate the flexural behavior of geocell reinforcement by means of three-layered beam model testing. The geocell reinforcement was assumed to be a continuous beam sandwiched between two identical polywood beams. An analytical analysis was conducted to derive the closed-form solution to calculate the deflection of the three-layered beam model. A series of four-point bending tests using dead weights were carried out to test the three-layered beam models. Two geocell products of different dimensions and two types of infill materials, crushed stone and silty sand were tested in this study. Deflections of the layered beam models were measured along with the increment of applied loads. Testing results showed that the geocell reinforcement provides considerable resistance to flexural deformation, especially at higher load levels. The geocell with greater cell height to cell length ratio exhibited overall greater resistance to flexural deflection, especially when crushed stone was used as infill materials. Geocell reinforcements filled by crushed stone showed less flexural deformation than the geocells filled by silty sand. The modulus of the geocell reinforcement was calculated based on the closed-form solution and deflection measurements from the four-point bending tests. Ranges of elastic modulus were presented for the geocell reinforcement filled with compacted crushed stone and silty sand, which can be used as reference values for material property inputs in mechanistic-empirical design of geocell-reinforced pavements.Geotechnical and Geological Engineering 31(2).
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ABSTRACT: This paper presents the results of investigation into bearing capacity of a geocell reinforced load base. In order to analyze variation of bearing capacity of the geocell reinforced road base comparing to without reinforced geocell road base, a series of full-scale tests were performed and measured using FWD (Falling Weight Deflectometer). The results indicate that bearing capacity of geocell (T=1.5 mm) reinforecd road base increase than the unreinforced road base.Journal of the Korean Geosynthetic Society. 01/2012; 11(3).