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.

Marine pipelines are widely used for transporting hydrocarbon material. However, they can be damaged by marine geo-hazards such as seabed liquefaction, as they may sink, float or be dragged by the moving soil. One of the triggering mechanism of seabed liquefaction is the increase of seabed inclination as a result of the souring process or human construction activities. Experiments are carried out to simulate seabed liquefaction and to study the drag forces on a shallowly buried gas pipe at a centrifugal acceleration field of 50g. A tilting mechanism is applied to trigger sample liquefaction. A fluidization system equipped at the bottom of the strongbox is designed to prepare fully saturated, loose and uniform samples. Viscous fluid made of Hydroxypropyl Methylcellulose powder is used as the pore fluid. A hollow model pipe is embedded in the sand layer shallowly with a specific embedment ratio. The pipe fixities are made to be adjustable for adjusting pipe locations horizontally and vertically. Strain gauges attached on fixities are used to monitor the loads exerted on the pipe. The effect of the presence of pipes on the sand layer instability is presented. Furthermore, the drag forces acting on the pipe at a specific embedment ratio is discussed.