Rd
R.E.P. de Nijs
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3 records found
1
Grouting the tail void
Analysis of the tail void grouting process at the North/South line
Master thesis
(2020)
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Michiel Vonk, Wout Broere, Kristina Reinders, Richard de Nijs, Frank Kaalberg
To fight increasing traffic in city centres, tunnelling can be used to move traffic under the surface of the busy city. However, to prevent damage to the surrounding buildings, the settlements induced by the tunnelling should be kept to a minimum. This thesis researches the influence of the TBM tail void and its grouting process on the settlements. To do so, the monitoring and TBM data from the North/South line in Amsterdam is used. The data of the settlements, grout pressures and grout volumes is searched for locations with sudden changes. For these locations, the development of the settlements as a function of the TBM movement is compared to find out if the changes in settlements are caused by the tail void. This turns out to be the case for half of the researched locations. Furthermore, the changes of the grout pressuresmeasured in the tail void, and the volume injected grout volume are compared for these locations. An increase in injected grout volume shows to decrease the settlements induced by the tail void, while the pressure does not show a correlation with the settlements. Because only one sensor was used for the pressuremeasurements, the grout pressures are then compared for all sensors in the tail void. Again, no correlation is found between the grout pressures and the settlements. A side step in the research shows the development of the grout pressures in the tail void. During the boring process the grout pressures fluctuate. During the boring and forward movement of the TBM the tail void is injected with grout and the grout pressures in the tail void increase. During the ring building phase, this grouting stops and the grout pressures start to dissipate. The amount of dissipation is influenced by the permeability of the surrounding soil. With the help of DIANA FEM software, the influence of the tail void on the total settlements is investigated. The calculations show that a different grouting behaviour caused a change of only 4mmin total settlements. Concluding, as long as the pressures in the tail void stay above the soil pressure the tail void can be filled with grout. The injected grout volume will fill the tail void, preventing the soil from moving into the tail void and with that minimising the settlements at the surface.
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To fight increasing traffic in city centres, tunnelling can be used to move traffic under the surface of the busy city. However, to prevent damage to the surrounding buildings, the settlements induced by the tunnelling should be kept to a minimum. This thesis researches the influence of the TBM tail void and its grouting process on the settlements. To do so, the monitoring and TBM data from the North/South line in Amsterdam is used. The data of the settlements, grout pressures and grout volumes is searched for locations with sudden changes. For these locations, the development of the settlements as a function of the TBM movement is compared to find out if the changes in settlements are caused by the tail void. This turns out to be the case for half of the researched locations. Furthermore, the changes of the grout pressuresmeasured in the tail void, and the volume injected grout volume are compared for these locations. An increase in injected grout volume shows to decrease the settlements induced by the tail void, while the pressure does not show a correlation with the settlements. Because only one sensor was used for the pressuremeasurements, the grout pressures are then compared for all sensors in the tail void. Again, no correlation is found between the grout pressures and the settlements. A side step in the research shows the development of the grout pressures in the tail void. During the boring process the grout pressures fluctuate. During the boring and forward movement of the TBM the tail void is injected with grout and the grout pressures in the tail void increase. During the ring building phase, this grouting stops and the grout pressures start to dissipate. The amount of dissipation is influenced by the permeability of the surrounding soil. With the help of DIANA FEM software, the influence of the tail void on the total settlements is investigated. The calculations show that a different grouting behaviour caused a change of only 4mmin total settlements. Concluding, as long as the pressures in the tail void stay above the soil pressure the tail void can be filled with grout. The injected grout volume will fill the tail void, preventing the soil from moving into the tail void and with that minimising the settlements at the surface.
This master thesis aims to do a detailed conceptual design of a tunnel to connect the road A15 and A12, which will cross the Pannerdens canal ( represented by red color in figure 1.1) and a deep comparisonwith the bridge plan solution which has already been adopted by the government, which was named ViA15 project.
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This master thesis aims to do a detailed conceptual design of a tunnel to connect the road A15 and A12, which will cross the Pannerdens canal ( represented by red color in figure 1.1) and a deep comparisonwith the bridge plan solution which has already been adopted by the government, which was named ViA15 project.
The Impact of micro-tunnelling on adjacent pile foundations
Numerical modelling of micro-tunnel excavation in PLAXIS
A series of finite element simulations via PLAXIS were carried out to investigate the effects of micro- tunnelling on nearby pile foundations. A numerical model concerning the large diameter tunnel boring machine was first established based on identical properties of the centrifuge experiment executed by Loganathan et al. (2000). Results from numerical simulation were validated by measured data from the centrifuge test. After the validation of the numerical modelling method, the model was adjusted to match the case of micro-tunnel and a new model regarding the micro-tunnelling procedure was generated based on geotechnical conditions of the North/South Metro Line Amsterdam. The Hardening Soil constitutive model was chosen for all soil layers. In the model, the condition of single bored pile with working load was activated in the greenfield condition before the simulation of micro- tunnel. Advancement procedure of the micro-tunnel was simulated, and pile responses were collected under the plane strain condition. Based on the study of the model, two load transfer mechanisms of piles during tunnel-pile interaction process were identified. Impact of tunnel advancement on adjacent piles was also interpreted. A set of parametric studies were implemented to study changes of pile settlement and bearing capacity with increasing volume loss. An influence zone around the micro- tunnel respecting the potential of pile critical movements was established. Although the lack of field data makes the validation of results hard, comparison with analytical prediction and measured data from the centrifuge test shows good agreements for soil movements and pile responses. The results of this research remain to be validated by field data but it can provide insights into the problem of the impact of micro-tunnelling on piles.
...
A series of finite element simulations via PLAXIS were carried out to investigate the effects of micro- tunnelling on nearby pile foundations. A numerical model concerning the large diameter tunnel boring machine was first established based on identical properties of the centrifuge experiment executed by Loganathan et al. (2000). Results from numerical simulation were validated by measured data from the centrifuge test. After the validation of the numerical modelling method, the model was adjusted to match the case of micro-tunnel and a new model regarding the micro-tunnelling procedure was generated based on geotechnical conditions of the North/South Metro Line Amsterdam. The Hardening Soil constitutive model was chosen for all soil layers. In the model, the condition of single bored pile with working load was activated in the greenfield condition before the simulation of micro- tunnel. Advancement procedure of the micro-tunnel was simulated, and pile responses were collected under the plane strain condition. Based on the study of the model, two load transfer mechanisms of piles during tunnel-pile interaction process were identified. Impact of tunnel advancement on adjacent piles was also interpreted. A set of parametric studies were implemented to study changes of pile settlement and bearing capacity with increasing volume loss. An influence zone around the micro- tunnel respecting the potential of pile critical movements was established. Although the lack of field data makes the validation of results hard, comparison with analytical prediction and measured data from the centrifuge test shows good agreements for soil movements and pile responses. The results of this research remain to be validated by field data but it can provide insights into the problem of the impact of micro-tunnelling on piles.