| 1. |
- Andersson, Patrik, 1974, et al.
(author)
-
Framtidsbilder för samhällsbyggnad
- 2006
-
Reports (other academic/artistic)abstract
- Framtidsbilder för samhällsbyggnad 2020De kommande 15 åren står institutionen för Bygg- och miljöteknik inför stora förändringar. Därför har institutionen initierat projektet Framtidsbilder 2020 där man engagerat en framtidspanel bestående av elva yngre disputerade forskare. Arbetet inleddes med ett breddgruppsmöte där 110 personer representerande institutionens personal och studenter deltog. Vid mötet identifierades ett antal trender och osäkra utvecklingar som påverkar framtiden inom samhällsbyggnadsområdet. Deltagarna bidrog också med idéer till en önskvärd utveckling, vilket har sammanställts och utgör grunden till en gemensam önskvärd framtid/vision för institutionen. Materialet från breddgruppsmötet har bearbetats av Framtidspanelen och resulterat i fyra scenarier som beskriver hur samhällsbyggnadsområdet kan se ut år 2020. Syftet med framtidsbilderna är att de ska vara vägledande för institutionens beslut och förhållningssätt under de kommande åren.Fyra scenarierTurning TorsoSamhället präglas av en ekonomi som är på uppgång, och av ett nytänkande och öppet samhälle. Materiell status och individualism är viktigt. Detta leder till en hög arbetsbelastning samt krav på exklusiva varor av hög kvali-tet. Det finns en stor medvetenhet om miljöpåverkan och klimatförändringar och lösningarna för att klara energiförsörjningen är innovativa.Eco-metropolenDet sveper en grön våg genom dagens samhälle. Under de senaste 15 åren har vi insett att jorden skall vara en bebolig plats även åt dem som kommer efter oss. Vi söker ständigt efter nya, mer förfinade metoder att tillvarata de resurser vi har. Samhället och individen är i balans. Ekonomin är god och vi är miljömedvetna, trygga och integrerade. Nytänkande premieras och icke- materialistiska värderingar står högt i kurs. Vi tänker individuellt, men agerar mer än gärna för kollektivets bästa. Utbildning är gratis TrädgårdsstadenEtt samhälle där vi lärt oss hantera stress, men känner oss otrygga och helst umgås i slutna sociala sammanhang. Vi bor enkelt inne i stan, eller gärna på landsbygden nära storstäderna. Minskade behov av högutbildade i samhället gör att vi har svårt att rekrytera studenter till teknikutbildningar. Det traditionella tankesättet leder till kulturkrockar med företag och personer från andra länder.Gated communitiesFörsämrad ekonomi och ökad egoism har lett fram till ett stressat, otryggt och segregerat samhälle. Accelererande klimatförändringar och ökad miljö-påverkan skrämmer oss, men trots det åtgärdar vi inte problemen, utan koncentrerar oss på konsekvenserna. Arbetslöshet i samhällsbyggnadssek-torn leder till sänkt status för samhällsbyggaren. Vi har därför svårt att rekrytera studenter, och även forskningen har låg status.
|
|
| 2. |
- Bernander, Stig, et al.
(author)
-
Downhill progressive landslides in long natural slopes: triggering agents and landslide phases modeled with a finite difference method
- 2016
-
In: Canadian geotechnical journal (Print). - : Canadian Science Publishing. - 0008-3674 .- 1208-6010. ; 53:10, s. 1565-1582
-
Journal article (peer-reviewed)abstract
- A large landslide in Tuve (Gothenburg, Sweden 1977) initiated the development of a model for slope stability analysis taking the deformation-softening of soft sensitive clays into consideration. The model studies triggering agents and five phases in progressive slope failure are identified: (1) in-situ, (2) disturbance, (3) unstable ‘dynamic’, (4) transitory (or permanent) equilibrium, and (5) ‘global’ failure. The clay resistance in these phases may differ widely; mostly due to different rates of loading. Two time dependent failure criteria are defined: (i) the triggering load condition in the disturbance Phase (2), and (ii) the transitory equilibrium in Phase (4), indicating whether minor downhill displacements or a veritable landslide catastrophe will occur. The analysis explains why downhill landslides tend to spread over vast areas of almost horizontal ground further down-slope. The model has been applied to landslides in Scandinavia and Canada. Three case studies are briefly discussed. The model is a finite difference approach, where local downhill deformations caused by normal forces is maintained compatible with deviatory shear deformations above the potential (or the established) failure surface. Software and an easy-to-use spreadsheet are introduced as well as recent developments. See also Video Abstract.
|
|
| 3. |
- Tornborg, Johannes, 1984, et al.
(author)
-
Benchmarking of a contemporary soil model for simulation of deep excavations in soft clay
- 2019
-
In: Proceedings of the XVII European Conference on Soil Mechanics and Geotechnical Engineering. - 9789935943613
-
Conference paper (peer-reviewed)abstract
- Measurement data from previous excavation works in soft clay deposits are revisited to benchmark a contemporary constitutive soil model, referred to as the Creep-SCLAY1S. The research is motivated by the planned deep excavations for the West Link tunnel in Gothenburg that require analyses of both short- and long-term performance. Unique data on prior excavation works, which were instrumented and monitored during the construction period, will be utilised. In contrast to previous studies, that focused on the construction period, also the long-term performance will be assessed using satellite data. The analyses are carried out using a contemporary rate-dependent model, considering the on-going (background) creep deformations in the clay deposit. The study shows that while the recent model developments result in improved predictions, additional features need to be further developed: most notably, the formulations for the rate-dependent small strain stiffness in loading and unloading stress paths requires attention. Also, it is evident that modelling details, such as installation effects (sheet pile wall and pre-cast concrete displacement piles) are important for prediction of the subsequent response.
|
|
| 4. |
- Tornborg, Johannes, 1984, et al.
(author)
-
Experience from short-and long-term performance of deep excavations in soft sensitive clays
- 2021
-
In: IOP Conference Series: Earth and Environmental Science. - : IOP Publishing. - 1755-1307 .- 1755-1315. ; 710:1
-
Conference paper (peer-reviewed)abstract
- Design of excavations and permanent underground structures requires accurate predictions of e.g. deformations and earth pressures for both the short-and long-term. As excavation depths increase and/or the proximity to adjacent infrastructure decreases, there is a need to improve and develop existing design methods and validate numerical models. The first part of this paper revisits the measurement data from a previous excavation, the Göta Tunnel in Gothenburg, Sweden, in order to benchmark a contemporary constitutive soil model, called Creep-SCLAY1S. This study looks into time series including e.g. final dewatering of the excavation, followed by the development of pore water pressures, earth pressures and deformations over time (until 2 years after excavation). The model predictions are in general in good agreement with the measurement data up to final dewatering. However, installation effects due to drilling are believed to have caused continued deformations which are difficult to capture in the numerical model. Part two of the paper presents details of a recently instrumented excavation in soft clay in Central Gothenburg. The measurement data comprises e.g. pore water pressures, deformations as well as vertical and horizontal earth pressures at three locations under the permanent structure. Continued long-term measurements are planned and the existing and future data are believed to provide valuable insights on the development of the stress state and earth pressures under permanent structures in soft clay.
|
|
| 5. |
- Tornborg, Johannes, 1984, et al.
(author)
-
Modelling the construction and long-term response of Göta Tunnel
- 2021
-
In: Computers and Geotechnics. - : Elsevier BV. - 0266-352X .- 1873-7633. ; 134
-
Journal article (peer-reviewed)abstract
- This paper presents a benchmark of a rate-dependent constitutive model for soft soils, implemented in a 2D finite element code, against the response of an instrumented excavation in sensitive clay: Göta Tunnel in Gothenburg. The monitoring data, which comprise time-series of pore water pressures, displacements, earth pressures and strut forces, provide valuable insights of the time-dependent response during the construction period. The long-term response, in terms of the ongoing settlement rates, is assessed using remote sensing data. The results of the numerical simulations demonstrate that the constitutive model, Creep-SCLAY1S, is capable of capturing the observed response. The trends of vertical and horizontal displacements are captured well until the stage of dewatering, and the evolution of pore pressures and earth pressures is computed with high accuracy, excluding peaks in the measurement values arising from pile and rock anchor installation. Most importantly, the results demonstrate that the rate-dependent model enables to model the complete service life of the tunnel, from construction of the excavation to the tunnel operation, with one unified model parameter set. Furthermore, the comparisons highlight the importance of assessing installation effects both in the choice of construction methods and modelling.
|
|
| 6. |
- Dury, Robin, 1994-, et al.
(author)
-
Progressive Landslide Analysis with Bernander Finite Difference Method
- 2017
-
Conference paper (other academic/artistic)abstract
- The poster presents a new Spreadsheet developed by Robin Dury (2017) to simplify the use of the Finite Difference Method developed by Stig Bernander et al (2011, 2016).It includes:- Material Properties- Finite Difference Method- Progressive failure process with five phses- Discussion- References
|
|
| 7. |
- Kullingsjö, Anders, 1974
(author)
-
Effects of deep excavations in soft clay on the immediate sourroundings-Analysis of the possibility to predict deformations and reactions against the retaining system
- 2007
-
Doctoral thesis (other academic/artistic)abstract
- When excavating in an urban environment, the evaluation of the magnitude and distribution of ground movements is an important part of the design process, since excessive movements can damage adjacent buildings and utilities. In order to minimize movement of the surrounding soil, a retaining wall support system is used for deep excavations to provide lateral support. This dissertation describes different methods of evaluating ground movements adjacent to a deep excavation in soft clay and how to estimate the lateral earth pressure acting on the retaining wall system. A review is presented regarding:-Soil characteristics that are important for evaluation of deformations and earth pressure.-Current empirical methods of estimating ground surface settlements-Different classic methods of calculating lateral earth pressure-Various soil modelling methods, with focus on the theory of elasto-plasticity.This review is followed by an extensive case study performed at the Göta tunnel project, in the centre of Gothenburg, Sweden.Back analyses were performed in order to predict and interpret ground deformations and the development of stress changes against the retaining wall system. These analyses took the form of non-linear finite element analyses with three different constitutive models (an isotropic linear elastic Mohr-Coulomb model, e-ADP, a total stress based model capable of modelling anisotropic undrained shear strength as well as non-linearity in shear, and MIT-S1, a bounding surface model based on effective stresses. The different outcomes of these three models are compared and discussed. Special focus has been on evaluating the parameters to the MIT-S1 model and to evaluate the response of this model compared against advanced laboratory tests.The outcome of the analyses shows the advantage, compared to simpler models, of using finite element methods in combination with an advanced soil model, such as the MIT-S1, capable of simulating small strain stiffness, non-linear elasticity, non-linearity in shear and the development of shear induced excess pore water pressure. The analyses also show the importance of combining FE-analyses with empirical methods for estimating ground surface settlements.The field monitoring also demonstrated that deformations obtained by shear strength mobilization may be overshadowed by other engineering activities and poor workmanship. Close collaboration between the contractor and geotechnical consultant is of paramount importance.
|
|
| 8. |
- Kullingsjö, Anders, 1974
(author)
-
Effects of deep excavations in soft clay on the immediate surroundings
- 2009
-
In: 17th International Conference on Soil Mechanics and Geotechnical Engineering, ICSMGE 2009; Alexandria; Egypt; 5 October 2009 through 9 October 2009. - 9781607500315 ; 3, s. 1923-1930
-
Conference paper (peer-reviewed)abstract
- When excavating in an urban environment, evaluation of the magnitude and distribution of ground movements is an important part of the design process, since excessive movement can damage adjacent buildings and utilities. In order to minimize the movement of the surrounding soil, a retaining wall support system is used to provide lateral support. This article is a brief summary of the dissertation "Effects of Deep Excavations in Soft Clay on the Immediate Surroundings: Analysis of the Possibility to Predict Deformations and Reactions Against the Retaining System" presented at Chalmers in 2007, (Kullingsjö, 2007). The dissertation describes different methods for the evaluation of ground movements adjacent to a deep excavation in soft clay as well as how to estimate the lateral earth pressure that acts on the retaining system. It presents a review of: - Soil characteristics of importance for the evaluation of deformations and earth pressure. - Current empirical methods for estimating ground surface settlements. - Different classical methods for calculating lateral earth pressure. - Various soil modelling methods, with focus on the theory of elasto-plasticity. The review is followed by an extensive case study performed at the Göta tunnel project in the centre of Gothenburg, Sweden. Back analyses were performed in order to predict and interpret ground deformations and the development of stress changes against the retaining wall system. These analyses took the form of non-linear finite element analyses with three different constitutive models (an isotropic linear elastic Mohr-Coulomb model, the e-ADP, which is a total stress based model capable of modelling anisotropic undrained shear strength as well as non-linearity in shear, and MIT-S1, a bounding surface model based on effective stresses). The different outcomes of these three models are compared and discussed. Special focus has been placed on evaluating the parameters of the MIT-S1 model and its response compared to advanced laboratory tests.
|
|
