DOI: 10.5593/SGEM2015/B12/S2.002


B. Bozhinov, I. Bozhinova-Popova
Friday 7 August 2015 by Libadmin2015

References: 15th International Multidisciplinary Scientific GeoConference SGEM 2015, www.sgem.org, SGEM2015 Conference Proceedings, ISBN 978-619-7105-32-2 / ISSN 1314-2704, June 18-24, 2015, Book1 Vol. 2, 9-16 pp

The landslide section on the road between Balchik and Albena is in the area of Sviloza Factory. The landslide length (along the movement of the earth masses) is more than 350 m and its width is more than 400 m. The total area threatened by landslide phenomena is more than 300 decares. The landslide section threatens a district from the town of Balchik which is densely populated with country houses. The landslide depth in its upper part is from 24 to 28 m and in its lower part at the sea it is from 45 to 50 m. The slide has no shallow sections. The total volume of the landslide soil masses is approx. 3 – 3.5 million m3. The rock mass movement was recorded as early as 1994 and during the construction of the retaining and drainage structures in 1998 displacements of 37 mm occurred in its upper part at a rate of movement 0.02 mm/day, and 3402 mm in the lower part at a rate of movement 4.84 mm/day.
The retaining and drainage structure consists of two octagonal shafts filled with slurry walls, 80 cm thick and 26 m deep, driven at 1.5 m in the underlying marls below the sliding surface. Six rope anchors, each 35 m long, have been built in the upper end of the walls. The design load of the anchors is 750 kN. Horizontal boreholes with lengths of 40 m each have been drilled in the lower end of the shafts. The resistance capacity of each shaft is more than 15000 kN.
After building the main structure in the middle of the landslide section, additional load-carrying structures of anchor piles and slurry walls were constructed on the sides.
After executing the structures, the landslide processes stopped towards 2015. The dynamometers placed on the anchors were strained to 700 kN which after some time exhibited a force of 5700 kN.
The construction of such structures has proven their efficiency for deep and voluminous landslides.

Keywords: landslide, slurry walls, anchors, drainage boreholes, shafts