Bioengineering Techniques for Soil Erosion Protection and Slope Stabilization

The use of bio-engineering methods for soil erosion protection and slope stabilization has a long tradition. Old methods with rocks and plants, structures of timber have been used over the past centuries. Recently these old soil conservation and stabilization techniques have been rediscovered and improved. Biotechnical engineering methods have become part of geotechnical and hydraulic engineering and have helped bridge the gap between classical engineering disciplines, land use management, landscape architecture and biological sciences. In this paper the different uses of plants in hydraulic and geotechnical engineering design are presented. The core of this study is a comprehensive overview of the most important biotechnical construction methods used for soil erosion protection and slope stabilization. Methods, construction procedure, and the major advantages and disadvantages of these biotechnical methods are discussed. Considerations about construction and maintenance costs conclude in this paper.

Physical and mechanical characterization of the soft pyroclastic rocks forming the Orvieto cliff

The paper describes the results of laboratory and in situ investigations carried out on weak pyroclastic materials which could be encountered during engineering activities in volcanic regions. The research was focused on the historical town of Orvieto, representing a typical geotechnical situation which is widespread in Central Italy. The in situ investigations include cross-hole and SASW measurements performed in adjacent areas. The laboratory tests provided static and dynamic properties which were compared to the in situ data, in order to reconstruct the geotechnical model of a representative area of the town

Assessment of Karstification Degree in the Copacabana Group for a Tailings Dam Foundation, South Andes, Peru

The world-wide occurrence of carbonate rocks is extensive, and Peru is no exception. Many mining facilities are located in or on carbonate rocks. Under specific conditions, carbonate rocks show varying degrees of karstification, which represent a potential high risk of damage or failure to mine facilities, especially tailings and water impoundments due to subsidence or internal erosion problems. Adequate engineering measures, including proper characterization of the foundation materials, should be taken to characterize foundation materials and mitigate the risk. This paper presents the assessment of the potential of karst dissolution in the Copacabana Group underlying about 50% the foundation of a proposed tailings dam and storage facility, located in the South Andes of Peru. A thorough geotechnical site investigation program was carried out in the area, which included regional and local geological mapping, geotechnical drilling, test pits, permeability tests, effervescence test in cores, petrographic analyses, and X-Ray diffraction tests. Hydrogeological studies, such as pumping and tracer tests, were also performed by other consultants to verify the observations, conclusions, and opinions developed from the geotechnical investigation program. The results of the geotechnical investigation allowed proper characterization of the dam foundation and the tailings storage facility and estimation of the degree of karstification in the carbonate rocks of the Copacabana Group. The completed geological site characterization was then used to locate the tailings dam and impoundment area to avoid areas of pervasive karst and to implement defensive engineering measures, including grout curtains and slush grouting of smaller cavities and joints, among others

Engineering geology maps of the UK

School and university students of geology, engineering geology and geotechnical engineering generally have less knowledge of engineering geological conditions than those who have had experience of hands-on research or practice. In the UK, the number of geology, geoscience and earth science departments has reduced over the past 25 years. Engineering geology has a very weak academic base and geology is taught less to civil engineering students than previously

Dimensional Analysis: Overview and applications to problems of Soil-Structure Interaction

Dimensional Analysis is a long-established tool widely used in many branches of engineering and science. However, applications in geotechnical engineering, and in particular soil-structure interaction (SSI), have barely been explored, in spite of the method's potential to clarify parameter influence and shed light on the range of response regimes. The purpose of this text is twofold: (a) it intends to provide a brief introduction to Dimensional Analysis specifically tailored to geotechnical engineers by carefully choosing illustrative examples, (b) it uses Dimensional Analysis to study the parameter space in soil-building interaction problems, emphasizing modeling choices and using a finite-element model to demonstrate the concept of physical similarity. The suitability of using certain dimensionless parameters over others is discussed based on and their magnitude and sensitivity analysis

Assessing the contribution of vegetation to slope stability

Many embankments and cuttings associated with the transportation infrastructure in the UK are only marginally stable. Engineering techniques such as soil nailing, geosynthetic reinforcement, improved drainage and ground improvement by stabilisation are available to improve stability but the cost can be high. A lower cost solution may be to utilise vegetation, either self seeded or planted. The benefits and drawbacks associated with vegetation have been the subject of some debate. The problems caused by vegetation in relation to building foundations are well documented and confirm that vegetation can have very significant influences on geotechnical parameters. Appropriate properly maintained vegetation can have the same significant influence to help provide additional stability to soil slopes. This paper considers the potential engineering influences of vegetation and how it can be characterised on site within a geotechnical framework for stability assessments. The direct reinforcement available from the roots of trees and shrubs is identified as providing one of the most significant contributions to slope stability. Case studies in the UK, Greece and Italy demonstrate how results from in-situ root pull out tests may be used to estimate the potential reinforcement forces available from the roots. A scheme is presented to designate zones of influence within the soil according to the size and nature of the vegetation