Repair of Landslide Umka-Duboka — Seismic Performance Assessment

The Umka-Duboko is a large active landslide in the depth of 10-26 m, created in marly clays, taking up the area of 1.8 sq.km. According to the fact that the new road facility corridor located at the right bank of Sava river, on the meandering apex, crosses the landslide in the length of 3 km the characteristic remediation design solution is given. In this paper is observed seismic performance of this project. The analysis of potential liquefaction in motorway embankment and seismic stability of slope retained by embankment and hydraulic structure were made. The necessity was despite the limited seismic hazard data to give an assessment of potential maximal displacement of the slope and its rate of occurrence. The results obtained with used methodology are very good reference for a general design of this project and seismic performance assessment of landslides of this type

Geotechnical Issues in Structural Stabilization of Historical Monument — Clock Tower

Being located in the central Balkan region, the territory of the Republic of Macedonia has a significant historical heritage. The clock tower in city of Prilep, central Macedonia, dates back to the 19th century. With its total height of almost 30 m, it is one of the most remarkable monuments. During its serviceability period, the clock tower has suffered some moderate inclination. The presented study has been focused on geotechnical issues as part of a structural consolidation project for this important historical structure. In the last decade, in the period between 1998 – 2009, an inclination of 39mm was observed on the top of the clock tower. The measurements and monitoring of the Clock Tower have proved a tendency for further inclination. The paper presents the geotechnical aspects of the consolidation project, which mainly consisted of an extensive site investigation involving bore-holing and geophysical measurements, characterization of the foundation structure, site response analysis of the representative geotechnical soil models and investigation of the soil-structure interaction effects through a 3d numerical analysis of the existing and strengthened models of the clock tower. The results have revealed important issues that should be taken into consideration in preservation of historical monuments

Shaking Table Tests on Effiency of New Type of Drains

One method to mitigate liquefaction-induced hazard is the use of a system of vertical drains to dissipate the excess pore water pressure generated by earthquake loading. Performance assessments for these systems require the estimation of vertical drain spacing such that a maximum threshold level of excess pore pressure ratio is not exceeded. The objective of this research is to study efficiency of installing vertical drains on generation and dissipation of pore water pressure. For this purpose series of shaking table tests were performed using a laminar box, in Geotechnical Laboratory on Tokyo University. The ground model consists of two layers of saturated sand with relative densities of 80% and 40%. Two different types of vertical drains were investigated: prefabricated micro drain with diameter 22 mm and gravel drain with diameter of 30 mm. Several shaking table tests were performed with different distribution pattern in order to achieved optimal spacing between vertical drains on dissipation of pore water pressure. The tests were carried out with harmonic loading at frequency of 10 Hz and varying the magnitude of input acceleration in wide range from 0.05 to 0.60 (g). The results from above shaking table tests provided a detail view of efficiency of new type of vertical drains as one of the frequently used remedial measures against liquefaction

Simplified method for generating slope seismic deformation hazard curve

A simplified method for generating slope deformation hazard curve that takes into account the variations of input parameters is presented in this paper. The main assumption in the new approach is that the occurrence of peak slope deformation is Poisson's process. The procedure is based on logic tree analysis, commercial software and routines programmed by the authors for generating sets of input files, and forming slope performance curve. The methodology was applied to a real landslide in order to demonstrate the advantages and limitations of the proposed approach. The results of the analysis showed the influence of the certain input factors on sliding displacement as well as the advantages of employing continuum mechanics approach