The Experts below are selected from a list of 104064 Experts worldwide ranked by ideXlab platform
Johan Spross - One of the best experts on this subject based on the ideXlab platform.
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Probabilistic Observational Method for design of surcharges on vertical drains
Géotechnique, 2021Co-Authors: Johan Spross, Stefan LarssonAbstract:Preloading with a surcharge is today commonly used together with prefabricated vertical drains for embankment construction on clayey soil to accelerate primary consolidation and increase strength. ...
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Probabilistic evaluation of settlement monitoring with the Observational Method during construction of embankments on clay
2019Co-Authors: Johan Spross, Anders Prästings, Stefan LarssonAbstract:Preloading is commonly used to accelerate primary consolidation and increase strength under embankments founded on highly compressible clay. By installing prefabricated vertical drains, ...
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when is the Observational Method in geotechnical engineering favourable
Structural Safety, 2017Co-Authors: Johan Spross, Fredrik JohanssonAbstract:The Observational Method in geotechnical engineering is an acceptable verification Method for limit states in Eurocode 7, but the Method is rarely used despite its potential savings. Some reasons m ...
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Reliability aspects of rock tunnel design with the Observational Method
International Journal of Rock Mechanics and Mining Sciences, 2017Co-Authors: William Bjureland, Johan Spross, Fredrik Johansson, Anders Prästings, Stefan LarssonAbstract:According to Eurocode 7, two accepted approaches for managing uncertainty in tunnel design are reliability based Methods and the Observational Method. Reliability-based Methods account for uncertai ...
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Using Observational Method to Manage Safety Aspects of Remedial Grouting of Concrete Dam Foundations
Geotechnical and Geological Engineering, 2016Co-Authors: Johan Spross, Fredrik Johansson, Lauri Kalle Tapio Uotinen, Jalaleddin Yaghoobi RafiAbstract:As concrete dams age, the need for remedial grouting to reduce the seepage and uplift pressure in the rock foundations under them increases. Based on a case study of a Swedish dam with very low calculated safety against sliding, this paper discusses the application of the Observational Method (as defined in Eurocode 7) to manage safety aspects during remedial grouting. The studied case was complex in that grouting works posed the risk of causing increased uplift pressure, which could have induced sliding failure along a shallow, persistent, horizontal rock joint in the foundation. The approach applied in the studied case mainly followed the principles of the Observational Method, except in some highly significant safety aspects for which alternative procedures are suggested and discussed. Implementing these procedures along with the Observational Method offers a coherent framework to manage the safety aspects of the remedial grouting of concrete dam foundations that is in line with modern risk-informed dam safety policies.
Stefan Larsson - One of the best experts on this subject based on the ideXlab platform.
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Probabilistic Observational Method for design of surcharges on vertical drains
Géotechnique, 2021Co-Authors: Johan Spross, Stefan LarssonAbstract:Preloading with a surcharge is today commonly used together with prefabricated vertical drains for embankment construction on clayey soil to accelerate primary consolidation and increase strength. ...
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Probabilistic evaluation of settlement monitoring with the Observational Method during construction of embankments on clay
2019Co-Authors: Johan Spross, Anders Prästings, Stefan LarssonAbstract:Preloading is commonly used to accelerate primary consolidation and increase strength under embankments founded on highly compressible clay. By installing prefabricated vertical drains, ...
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Reliability aspects of rock tunnel design with the Observational Method
International Journal of Rock Mechanics and Mining Sciences, 2017Co-Authors: William Bjureland, Johan Spross, Fredrik Johansson, Anders Prästings, Stefan LarssonAbstract:According to Eurocode 7, two accepted approaches for managing uncertainty in tunnel design are reliability based Methods and the Observational Method. Reliability-based Methods account for uncertai ...
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Towards an Improved Observational Method
Rock Engineering and Rock Mechanics: Structures in and on Rock Masses, 2014Co-Authors: Johan Spross, Fredrik Johansson, Håkan Stille, Stefan LarssonAbstract:The Observational Method is today an accepted Method in Eurocode 7 for design of geotechnical structures. However, case studies with formal application of its principles are still rare. One reason ...
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On the Observational Method for groundwater control in the Northern Link tunnel project, Stockholm, Sweden
Bulletin of Engineering Geology and the Environment, 2014Co-Authors: Johan Spross, Stefan LarssonAbstract:For tunnelling in rock in Sweden, the public authorities usually set stringent requirements on low groundwater inflow to the tunnel, to minimise the risk of building settlement and the environmental impact. To improve this groundwater control, the potential application of the Observational Method in this matter was studied. A comparison was made between the actual implementation of groundwater control in the Northern Link road tunnel project in Stockholm and the definition of the Observational Method in Eurocode 7. The results showed that the groundwater control in the Northern Link project mainly agreed with the Eurocode. The significance of the deviations was discussed, and it was concluded that adopting the Observational Method for groundwater control so that it complied with Eurocode 7 would mostly entail simply a formalisation of today’s procedures.
Fredrik Johansson - One of the best experts on this subject based on the ideXlab platform.
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when is the Observational Method in geotechnical engineering favourable
Structural Safety, 2017Co-Authors: Johan Spross, Fredrik JohanssonAbstract:The Observational Method in geotechnical engineering is an acceptable verification Method for limit states in Eurocode 7, but the Method is rarely used despite its potential savings. Some reasons m ...
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Reliability aspects of rock tunnel design with the Observational Method
International Journal of Rock Mechanics and Mining Sciences, 2017Co-Authors: William Bjureland, Johan Spross, Fredrik Johansson, Anders Prästings, Stefan LarssonAbstract:According to Eurocode 7, two accepted approaches for managing uncertainty in tunnel design are reliability based Methods and the Observational Method. Reliability-based Methods account for uncertai ...
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Using Observational Method to Manage Safety Aspects of Remedial Grouting of Concrete Dam Foundations
Geotechnical and Geological Engineering, 2016Co-Authors: Johan Spross, Fredrik Johansson, Lauri Kalle Tapio Uotinen, Jalaleddin Yaghoobi RafiAbstract:As concrete dams age, the need for remedial grouting to reduce the seepage and uplift pressure in the rock foundations under them increases. Based on a case study of a Swedish dam with very low calculated safety against sliding, this paper discusses the application of the Observational Method (as defined in Eurocode 7) to manage safety aspects during remedial grouting. The studied case was complex in that grouting works posed the risk of causing increased uplift pressure, which could have induced sliding failure along a shallow, persistent, horizontal rock joint in the foundation. The approach applied in the studied case mainly followed the principles of the Observational Method, except in some highly significant safety aspects for which alternative procedures are suggested and discussed. Implementing these procedures along with the Observational Method offers a coherent framework to manage the safety aspects of the remedial grouting of concrete dam foundations that is in line with modern risk-informed dam safety policies.
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Towards an Improved Observational Method
Rock Engineering and Rock Mechanics: Structures in and on Rock Masses, 2014Co-Authors: Johan Spross, Fredrik Johansson, Håkan Stille, Stefan LarssonAbstract:The Observational Method is today an accepted Method in Eurocode 7 for design of geotechnical structures. However, case studies with formal application of its principles are still rare. One reason ...
S H Chew - One of the best experts on this subject based on the ideXlab platform.
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comparison of the hyperbolic and asaoka Observational Method of monitoring consolidation with vertical drains
Soils and Foundations, 1996Co-Authors: S A Tan, S H ChewAbstract:The use of vertical drains and surcharge to accelerate the consolidation of clayey soils is well established in soil improvement technology. For this Method of soil treatment, it is important to monitor the progress of consolidation where the average degree of consolidation is usually defined as the ratio of current settlement to the ultimate settlement due to primary consolidation. An accurate estimate of the ultimate primary settlement is, therefore, required in order to determine the state of consolidation, and the appropriate time for surcharge removal when the desired degree of consolidation has been achieved. Recently, Tan (1995) proposed a new hyperbolic Method to identify the 60% and the 90% consolidation stages from field settlement data due to one dimensional consolidation. Knowing the settlement at these points, it is possible to determine the ultimate primary settlement. Once sufficient data has been recorded to identify the linear portion of the hyperbolic plot between the 60% to 90% consolidation stages, the Method can be employed. This Method has been validated by application to various well documented case histories in the published literature. In Japan, however, Asaoka's Method for estimating ultimate primary settlement from field observation has been widely used and is well accepted by the geotechnical engineering community. This research paper presents a comparison of two different Observational Methods for monitoring the progress of consolidation to determine their similarity and differences, and their accuracy of predictions compared to actual observations. First, the theoretical basis of the two Methods are examined. It was found that settlement data beyond the 60% consolidation stage are needed in both Methods to make accurate predictions of ultimate primary settlement. Next, both Methods are applied to oedometer laboratory consolidation data for kaolin specimens in order to determine how prediction of ultimate primary settlement and coefficient of consolidation would compare in carefully controlled laboratory experiments. Finally, both Methods are applied to several well documented case histories of vertical drain projects, and the predictions of ultimate primary settlement and in situ coefficient of consolidation are compared. It was found that both Methods gave good agreement with predictions, making them complementary tools for use in monitoring consolidation in field applications.
Simonetta Cola - One of the best experts on this subject based on the ideXlab platform.
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Innovative passive reinforcements for the gradual stabilization of a landslide according with the Observational Method
Landslides, 2021Co-Authors: Lorenzo Brezzi, Alberto Bisson, Davide Pasa, Simonetta ColaAbstract:A large number of landslides occur in North-Eastern Italy during every rainy period due to the particular hydrogeological conditions of this area. Even if there are no casualties, the economic losses are often significant, and municipalities frequently do not have sufficient financial resources to repair the damage and stabilize all the unstable slopes. In this regard, the research for more economically sustainable solutions is a crucial challenge. Floating composite anchors are an innovative and low-cost technique set up for slope stabilization: it consists in the use of passive sub-horizontal reinforcements, obtained by coupling a traditional self-drilling bar with some tendons cemented inside it. This work concerns the application of this technique according to the Observational Method described within the Italian and European technical codes and mainly recommended for the design of geotechnical works, especially when performed in highly uncertain site conditions. The Observational Method prescribes designing an intervention and, at the same time, using a monitoring system in order to correct and adapt the project during realization of the works on the basis of new data acquired while on site. The case study is the landslide of Cischele, a medium landslide which occurred in 2010 after an exceptional heavy rainy period. In 2015, some floating composite anchors were installed to slow down the movement, even if, due to a limited budget, they were not enough to ensure the complete stabilization of the slope. Thanks to a monitoring system installed in the meantime, it is now possible to have a comparison between the site conditions before and after the intervention. This allows the evaluation of benefits achieved with the reinforcements and, at the same time, the assessment of additional improvements. Two stabilization scenarios are studied through an FE model: the first includes the stabilization system built in 2015, while the second evaluates a new solution proposed to further increase the slope stability.
