Boštjan Pulko

Reinforced concrete shafts for the structural mitigation of large deep-seated landslides: an experience from the Macesnik and the Slano blato landslides (Slovenia)

During the last decade, several rainfall-induced deep-seated large landslides with volumes of the order of 1 million m3 were triggered in various locations in Slovenia (central Europe), each representing a serious threat to the nearby villages and traffic infrastructure and urging to be mitigated. The Macesnik landslide, triggered in 1989, and the Slano blato landslide, triggered in 2000, were the first two large landslides in Slovenia, where a combination of drainage and retaining works consisting of deep reinforced concrete (RC) shafts/wells was successfully used as a mitigation measure. This paper presents the field conditions and a brief history of the two landslides with emphasis on the design approach and method used for the stability analysis and the design of deep RC shafts/wells. In addition, the paper gives an insight into the problems associated with the execution of works and provides data about the behavior of the two landslides after drainage and retaining works were completed. The monitoring data show that the undertaken mitigation measures were efficient to improve the stability of both landslides and significantly reduce the risk.

Use of Automatic Target Recognition System for the Displacement Measurements in a Small Diameter Tunnel Ahead of the Face of the Motorway Tunnel During Excavation

During construction of the Šentvid tunnel a unique opportunity arose to measure the 3D displacements ahead of the motorway tunnel excavation face, since the exploratory tunnel was already constructed in the axis of the main tunnel. According to reviewed literature such measurements had not been performed yet and several problems regarding equipment and complete scheme of the experiment needed to be overcome. The paper gives a brief description of the Šentvid tunnel project, presents significant factors that affected the choice of the geodetic equipment and describes the scheme of the experiment. A special attention is focused on the problems relating to the operation of the instrument in demanding environmental conditions (water, dust).

Numerical Simulation of a Post-grouted Anchor and Validation with In-Situ Measurements

Prior to the pull-out test of a post-grouted ground anchor, numerical simulations were performed in order to predict the load-displacement behaviour of the structure. Advanced constitutive models were employed to simulate the pull-out test. The soil parameters were determined based on laboratory and in-situ investigations. The stress distribution along the soil was evaluated and the numerical model employed for the grout was capable of reproducing the crack pattern in the post-grouted body. The strains throughout the tendon were strongly influenced by the grout conditions. The measured and the predicted load-displacement curves agreed very well, suggesting that the assumptions for the soil and the grout were reasonable.