Reuleaux plasticity: improving Mohr-Coulomb and Drucker-Prager

The yielding of soil exhibits both a Lode angle dependency and a dependency on the intermediate principal stress. Ignoring these leads to a loss of realism in geotechnical analysis, yet neither of the widely used Mohr-Coulomb (M-C) or Drucker-Prager (D-P) models include both. This paper presents a simple pressure-dependent plasticity model based on a modified Reuleaux (mR) triangle which overcomes these limitations and yet (like the M-C and D-P formulations) allows for an analytical backward-Euler stress integration solution scheme. This latter feature is not found in more sophisticated (and computationally expensive) models. The mR deviatoric function is shown to provide a significantly improved fit to experimental data when compared with the M-C and D-P functions. Finite deformation finite-element analysis of the expansion of a cylindrical cavity is presented, verifying the use of the mR constitutive model for practical analyses

Door Grond Horizontaal Belaste Palen: Analyse case study "Brienenoord Corridor Rotterdam"

In onderliggend rapport wordt onderzocht in welke mate de verschillende rekenmodellen, die in de dagelijkse praktijk worden toegepast om de mate van de omgevingsbeïnvloeding door een ophoging te voorspellen, het werkelijke grondgedrag dat tijdens en na de uitvoering van de BRICOR-ophoging is gemeten kunnen voorspellen. In het onderzoek zijn, in volgorde van complexiteit en de daarmee samenhangende hoeveelheid aan benodigde input, de volgende rekenmodellen betrokken: het MSettle isotachen model, de methode IJsseldijk-Loof, de methode van Bourges en Mieussens, de verenmodellen MPile, MHorpile en MSheet en 2D PLAXIS. In het laatstgenoemde model is het gedrag van de slappe klei- en veenlagen met een aantal verschillende constitutieve modellen beschreven: Soft Soil (SS), Soft Soil Creep (SSC) en Hardening Soil (HS). Met de bovengenoemde modellen is getracht een zo goed mogelijke voorspelling te geven van de waterspanningen, de verticale gronddeformaties, de horizontale gronddeformaties en de paalvervormingen tijdens de bouw-, consolidatieen kruipfase. Overigens kunnen de modellen niet worden gebruikt om alle grootheden te kunnen voorspellen. De vragen, die op basis van het vergelijken van de voorspellingen door de geselecteerde rekenmodellen met de metingen moeten worden beantwoord, zijn de volgende: - Wat is de voorspellende waarde van de geselecteerde rekenmodellen voor de waterspanningen, de gronddeformaties en de paalvervormingen tijdens de aanleg, na het consolidatieproces en gedurende het kruipproces? - Hoe gevoelig zijn de voorspellingen voor variaties in parameters? - Wat is het verschil tussen de voorspelde verticale gronddeformatie op maaiveldniveau met MSettle en met PLAXIS? Oftewel, wat is het effect van de zijdelingse gronddeformatie op de maaiveldzettingen? - Kunnen de horizontale gronddeformaties met voldoende nauwkeurig worden bepaald met behulp van gemeten en/of door MSettle voorspelde zettingen, al dan niet gebruik makend van fitfactoren? - Welke verklaringen zijn er voor de verschillen tussen de voorspellingen met de rekenmodellen en tussen de voorspellingen en metingen

Impact of the Eemdijk full-scale test programme (Impact du programme d'essais à grande échelle Eemdijk)

Levees in the Netherlands have traditionally been constructed from soil. Climate change and land subsidence require heightening and/or reinforcing these existing levees. Traditional reinforcements demand additional space, which in some cases conflicts with existing buildings. Applying sheet pile walls in levees allows for strengthening while minimizing needed footprint. However, a validated design approach that complies with relevant regulations lacked. To enable validation, a full-scale field test programme has been performed near the town of Eemdijk (The Netherlands). This has resulted in better insight in the soil-structure interaction of the structurally reinforced levee, on soft soil, loaded by high water and uplift conditions. This paper describes the rationale behind the test setup and operation of the test programme in relation to the current design codes and guidelines. First the set of knowledge questions to be resolved is considered. These questions gave direction to the type of failure tests, the required instrumentation and the impact of conclusions.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Hydraulic Structures and Flood Ris

Eemdijk full-scale field test programme: sheet pile pullover tests (TProgramme d’essai terrain à taille réelle Eemdijk: essais de déformation et de rupture de murs palplanches)

Dikes in the Netherlands have traditionally been constructed with soil. Climate change and sub-sidence requires heightening and or reinforcing of these existing ground dikes. Traditional reinforcements de-mand additional space, which in some cases conflicts with existing buildings. Applying sheet pile walls in dikes allows for strengthening while minimizing the increase in footprint. However, a validated design approach that complies with relevant regulations lacks. To enable the validation of a proposed design approach, a full-scale field test programme (Eemdijkproef) was performed near the town of Eemdijk, The Netherlands. It consisted of a step wise approach: 1) sheet pile pullover tests, 2) ground dike stability test, 3) sheet pile dike stability test. All tests were loaded until failure occurred. The full-scale pullover tests (POT) consisted of 4 sheet pile configura-tions. The length of the sheet piles varies between 13 and 16m and the width of the panel varies between 1.8 and 4.2m. Both Z- and U-profiles have been tested. This paper presents the test setup, monitoring, measurements and first findings. The test program provides better insight in the soil-structure interaction of an embedded sheet pile in soft soil. Ultimately this will lead to a validated design approach for sheet pile walls in dikes.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Hydraulic Structures and Flood Ris

Eemdijk full-scale field test programme: ground dike and sheet pile dike failure test (Programme d’essai terrain à taille réelle Eemdijk: essais de déformation et de rupture pour une digue standard en terre et une digue renforcée avec palplanchesitre)

Dikes in the Netherlands have traditionally been constructed with soil. Climate change and subsidence requires heightening and or reinforcing these existing dikes. Traditional reinforcements demand additional space, which in some cases conflicts with existing buildings. Applying sheet pile walls in dikes allows for strengthening while minimizing the increase in footprint. However, a validated design approach that complies with relevant regulations lacks. To enable the validation of a proposed design approach, a full-scale field test programme (Eemdijkproef) was performed near the town of Eemdijk, The Netherlands. It consisted of a step wise approach: 1) sheet pile pullover tests, 2) ground dike stability test, 3) sheet pile dike stability test. All tests were loaded until failure occurred. The two similar test dikes were constructed at full scale (5m high, 25m wide, 60m long). In one dike an 18m long sheet pile wall was installed. This paper presents the test setup, monitoring, measurements and first findings. The test program provides better insight in the soil-structure interaction of the reinforced dike, on soft soil, under high water and uplift conditions. Ultimately this will lead to a validated design approach for sheet pile walls in dikes.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Hydraulic Structures and Flood Ris

Eemdijk full-scale field test programme: ground dike and sheet pile dike failure test (Programme d’essai terrain à taille réelle Eemdijk: essais de déformation et de rupture pour une digue standard en terre et une digue renforcée avec palplanchesitre)

Dikes in the Netherlands have traditionally been constructed with soil. Climate change and subsidence requires heightening and or reinforcing these existing dikes. Traditional reinforcements demand additional space, which in some cases conflicts with existing buildings. Applying sheet pile walls in dikes allows for strengthening while minimizing the increase in footprint. However, a validated design approach that complies with relevant regulations lacks. To enable the validation of a proposed design approach, a full-scale field test programme (Eemdijkproef) was performed near the town of Eemdijk, The Netherlands. It consisted of a step wise approach: 1) sheet pile pullover tests, 2) ground dike stability test, 3) sheet pile dike stability test. All tests were loaded until failure occurred. The two similar test dikes were constructed at full scale (5m high, 25m wide, 60m long). In one dike an 18m long sheet pile wall was installed. This paper presents the test setup, monitoring, measurements and first findings. The test program provides better insight in the soil-structure interaction of the reinforced dike, on soft soil, under high water and uplift conditions. Ultimately this will lead to a validated design approach for sheet pile walls in dikes

Impact of the Eemdijk full-scale test programme (Impact du programme d'essais à grande échelle Eemdijk)

Levees in the Netherlands have traditionally been constructed from soil. Climate change and land subsidence require heightening and/or reinforcing these existing levees. Traditional reinforcements demand additional space, which in some cases conflicts with existing buildings. Applying sheet pile walls in levees allows for strengthening while minimizing needed footprint. However, a validated design approach that complies with relevant regulations lacked. To enable validation, a full-scale field test programme has been performed near the town of Eemdijk (The Netherlands). This has resulted in better insight in the soil-structure interaction of the structurally reinforced levee, on soft soil, loaded by high water and uplift conditions. This paper describes the rationale behind the test setup and operation of the test programme in relation to the current design codes and guidelines. First the set of knowledge questions to be resolved is considered. These questions gave direction to the type of failure tests, the required instrumentation and the impact of conclusions

Eemdijk full-scale field test programme: sheet pile pullover tests (TProgramme d’essai terrain à taille réelle Eemdijk: essais de déformation et de rupture de murs palplanches)

Dikes in the Netherlands have traditionally been constructed with soil. Climate change and sub-sidence requires heightening and or reinforcing of these existing ground dikes. Traditional reinforcements de-mand additional space, which in some cases conflicts with existing buildings. Applying sheet pile walls in dikes allows for strengthening while minimizing the increase in footprint. However, a validated design approach that complies with relevant regulations lacks. To enable the validation of a proposed design approach, a full-scale field test programme (Eemdijkproef) was performed near the town of Eemdijk, The Netherlands. It consisted of a step wise approach: 1) sheet pile pullover tests, 2) ground dike stability test, 3) sheet pile dike stability test. All tests were loaded until failure occurred. The full-scale pullover tests (POT) consisted of 4 sheet pile configura-tions. The length of the sheet piles varies between 13 and 16m and the width of the panel varies between 1.8 and 4.2m. Both Z- and U-profiles have been tested. This paper presents the test setup, monitoring, measurements and first findings. The test program provides better insight in the soil-structure interaction of an embedded sheet pile in soft soil. Ultimately this will lead to a validated design approach for sheet pile walls in dikes

Erwinia chrysanthemi veel aangetroffen

Om de grote problemen met Erwinia, vooral in de hyacint en Zantedeschia, het hoofd te bieden is PPO bezig met een omvangrijk onderzoek naar beheersmaatregelen tegen deze bacteriën. In samenwerking met Plant Resarch International en met medewerking van een aantal bedrijven is in het afgelopen jaar informatie verzameld over Erwinia's in bloembollen en andere teelten. Een eerste stap naar een adequate aanpa

Erwinia chrysanthemi veel aangetroffen

Om de grote problemen met Erwinia, vooral in de hyacint en Zantedeschia, het hoofd te bieden is PPO bezig met een omvangrijk onderzoek naar beheersmaatregelen tegen deze bacteriën. In samenwerking met Plant Resarch International en met medewerking van een aantal bedrijven is in het afgelopen jaar informatie verzameld over Erwinia's in bloembollen en andere teelten. Een eerste stap naar een adequate aanpa