1,720,973 research outputs found
Environmental aspects in geosynthetic-soil reinforcement structures: The role of vegetation
No full textWherever ecological solutions are desirable, soil bioengineering methods in slope stabilisation and soil erosion control are becoming more widely used. In this context, the design and application of geosynthetic-reinforced soil structures with vegetated face steep slopes has long emphasized aspects of environmental impact. In engineering practice, vegetation is increasingly used to protect artifi cial and natural slopes against shallow landslides and for surfi cial erosion control. The potential use of protection forests to combat shallow slope instabilities is becoming increasingly important, especially in the light of recent landslides and debris/mud fl ows in certain regions, triggered by rainfalls with increased intensity. The presence of vegetation contributes to maintaining slope stability and to reducingsurface soil erosion, both by reinforcing soil shear resistance and influencing the hydro-geologic conditions of soil. Methods to measure and predict the effects of vegetation on mass-wasting processes have become of particular interest to both the academic and engineering communities. The roots of plants are anchored into the soil to support the above-ground parts of vegetation, thereby creating a reinforced soil matrix in which stress is transferred from the soil to the roots, increasing the overall strength of the matrix. The strength of rooted soil is, therefore, due to a combination of soil strength, root strength, and the strength of the bonds between the soil and roots. Vegetation influences slope stability and the erosion process with both mechanical and hydrological effects. In particular, the mechanical effects of vegetation (increase in soil shear strength) related to soil stabilisation will be described. Based on the analysis of available literature, the aim of this work is to present the specifi c role of vegetation in soil reinforcement applications through the analysis of fi eld investigation, experimental tests carried out on roots and on roots-soil systems and analytical and theoretical modelling. Due to lack of space, erosion applications will be not considered in this paper. The use of vegetation in works of civil engineering and landscaping has grown in importance, but specifi c design standards are still under discussion for the use of vegetation in slope stabilization. Therefore, the design and management of stabilization systems using plants require an accurate knowledge about the quantitative reinforcing root effects on soil strength
A new theoretical method to evaluate the peak and the residual pullout resistance of extruded geogrids embedded in granular soils.
No full textA theoretical method to predict the pullout behaviour of extruded geogrids embedded in granular soils
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Geosynthetic Engineering and Vegetation Growth in Soil Reinforcement Applications
No full textIn Italy, since early times, the environmental aspects have always been a key issue on the design and the application. Consequently, the geosynthetic reinforced soil structures consist of vegetated face steep slopes. Furthermore, the use of vegetation has also been recognized and incorporated in engineering practice for erosion control and for stabilization of shallow slopes. Vegetation influences slope stability and erosion process by both mechanical effects and hydrological effects. In particular, in the paper, the mechanical effects of vegetation related to soil stabilization will be described. The purpose of this paper is to present the specific role of vegetation in soil reinforcement applications, by means of the analysis of the available literature on the (i) factors affecting root reinforcement of soil, (ii) experimental tests carried out on roots and on roots-soil system, and (iii) analytical and theoretical models. The erosion applications will not treated in this paper. The use of vegetation in civil engineering and landscape works has grown in importance, even if the specific design standard concerning the use of vegetation for slope stabilization is still under discussion. Therefore, design and management of stabilization systems by plants require an accurate knowledge about the quantitative reinforcing root effects on soil strength
Modelling interference between the geogrid bearing members under pullout loading conditions
No full textThe main interaction mechanisms affecting the pullout resistance of geogrids embedded in soils are the skin friction between soil and reinforcement solid surface and the bearing resistance which develops against transversal elements. As regards bearing resistance the interference mechanism plays an important role: this can occur when the spacing between transversal members is lower than a threshold value, depending on the extensions of active and passive surfaces mobilized on bearing members. Based on the result of several large-scale pullout tests, a theoretical method to determine the peak pullout resistance of extruded geogrids embedded in a compacted granular soil is proposed. The method takes into account the interference mechanism due to the proximity of the transversal bearing members and works well for soil-geogrid interfaces in which scale effect is negligible
The influence of reinforcement geometry and confined tensile stiffness on post-cyclic pullout resistance
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