Laboratory experiments on the effects of antecedent moisture content and residue application on structural properties of a fragile soil

Abstract. During or immediately after rainfall many slope failures have been observed. The slope failure occurred due to rainfall infiltration that rapidly increase the pore pressure and trigger the slope failure. Numerous studies have been conducted to investigate the rainfall-induced slope failure, but the mechanism of slope failure is still not well clarified. To investigate mechanism of rainfall-induced slope failure laboratory experiments have been conducted in flume. The slope was prepared with sandy soil in flume with constant inclination of 45°, because most of rainfall-induced slope failure occurred in sandy soil and on steep slope. The hydrological parameters such as pore pressure and moisture content were measured with piezometers and advanced Imko TDRs respectively. The slope failure occurred due to increase in moisture content and rise in pore pressure. During the flowslide type of slope failure the sudden increase in pore pressure was observed. The higher moisture content and pore pressure was at the toe of the slope. The pore pressure was higher at the toe of the slope and smaller at the upper part of the slope. After the saturation the run-off was observed at the toe of the slope that erodes the toe and forming the gullies from toe to upper part of the slope. In the case antecedent moisture conditions the moisture content and the pore pressure increased quickly and producing the surface runoff at the horizontal part of the slope. The slope having less density suffer from flowslide type of the failure, however in dense slope no major failure was occurred even at higher rainfall intensity. The antecedent moisture accompanied with high rainfall intensity also not favors the initiation of flowslide in case of dense slope. The flowslide type of failure can be avoided by controlling the density of soil slope. Knowing such parameters that controls the large mass movement helpful in developing the early warning system for flowslide type of failure.

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Schutzbehandlung von Beton mit Silan- und Siloxanpräparaten / Protective Treatment of Concrete with Silane or Siloxane

Restoration of Buildings and Monuments ◽

10.1515/rbm-1999-5377 ◽

1999 ◽

Vol 5 (3) ◽

pp. 307-310

Author(s):

B. Nyman

Keyword(s):

Moisture Content ◽

Penetration Depth ◽

Laboratory Experiments ◽

Protective Treatment

Abstract By means of laboratory experiments it is shown that the penetration depth of a treatment of concrete with Silane depends strongly on the duration of suction and on the moisture content of the concrete. The necessary duration of suction can be estimated for any required penetration depth.

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Moisture Effective Diffusivity in Porous Media with Different Physical Properties

Defect and Diffusion Forum ◽

10.4028/www.scientific.net/ddf.258-260.207 ◽

2006 ◽

Vol 258-260 ◽

pp. 207-212

Author(s):

Miranda M.N.N. ◽

M.A. Silva

Keyword(s):

Porous Media ◽

Diffusion Coefficient ◽

Moisture Content ◽

Mass Transport ◽

Physical Properties ◽

Pore Size ◽

Structural Properties ◽

Effective Diffusivity ◽

Nay Zeolite ◽

Moisture Effective Diffusivity

In the drying of porous media, the mass transport occurs in the pores as well as on the surface of the solid. The mechanisms involved can take place simultaneously, influenced by the predominant one and can change depending on the moisture content. In this work, the moisture effective diffusivity was estimated in solids with distinct structural properties in order to verify the predominant mechanisms according to the moisture content, analyzing the influence of the physical properties. The materials studied were NaY Zeolite, Kaolin, Silica and Alumina. The results of diffusion coefficient present a minimum at low moisture content that can be related to pore size.

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