Geotechnical and Geodetic Surveys in Baku

Engineering geological conditions in Baku

Baku lies in the south-western part of the Absheron Peninsula and descends towards the Bay of Baku like an amphitheatre. The terrain rises in steps from low coastal marine terraces to an upper plateau in the north and west. The city is cut by ravines, steep slopes and closed depressions, and the coastal strip lies below global sea level.

The upper part of the sequence is dominated by Quaternary and Pliocene deposits: marine sands and sandy loams, loams, shell limestones and the thick clay strata beneath them. The thickness and strength of the limestone beds change over short distances: on one plot rock may be found at shallow depth, while on the neighbouring plot it is replaced by clays and sands. Data from an adjacent construction site therefore cannot be transferred to your plot with confidence — each project needs its own geological cross-section.

In the historic and industrial parts of the city the natural soils are often covered by made ground of varying thickness: construction debris, remains of old foundations, backfilled ravines and quarries. On former oilfields the ground may be contaminated with petroleum products, which affects both soil properties and how excavated material has to be disposed of.

Key construction risks in Baku

• Landslides. Landslide processes are recorded on steep slopes, especially where clay beds dip towards the slope and water accumulates; the slopes in the southern part of the city are most often discussed in this respect, especially the Bayil slope, where landslides have been recorded repeatedly since the 19th century. When building at the crest or toe of a slope, its stability must be assessed separately: excavating a foundation pit and adding load can reactivate old landslides.
• Made ground. Heterogeneous, uncompacted fill causes differential settlement of foundations. Its thickness and extent are established with boreholes and trial pits; as a rule, the foundation is taken through the fill to bear on natural soil, or the fill is replaced.
• Rising groundwater and waterlogging. In a number of districts, leaks from water supply and sewer networks, irrigation of green areas and disrupted natural drainage raise the groundwater level. Flooded basements and loss of strength in wetted clayey soils are the typical consequences.
• Saline soils and aggressive groundwater. Along the coast and around salt lakes, soils and groundwater are rich in water-soluble salts. This can make them aggressive to concrete and reinforcement and directly affects the choice of cement and waterproofing.
• Seismicity. Azerbaijan is a seismically active country, and Baku is no exception. The design seismic intensity is taken from the applicable standards and codes and refined for the ground conditions on site: saturated loose sands and made ground amplify seismic shaking.

Surveys typically required

The scope of work in Baku depends on the number of storeys, whether there is a basement or underground car park, and how close the site is to a slope or the shoreline. For multi-storey buildings the following are usually carried out:

• topographic survey and, in dense urban areas, an underground utility survey;
• borehole drilling and sampling to define the boundaries of fill, limestone and clay;
• cone penetration testing and dynamic probing to trace the density of sands and clays through the profile;
• near slopes, a geohazard assessment;
• groundwater level and regime and aggressiveness of groundwater and soils;
• seismic microzonation or a seismic survey to determine shear-wave velocity;
• testing of physical and mechanical properties, and strength tests for limestones.

Where a deep excavation is planned next to existing buildings, deformation and settlement monitoring of the neighbouring structures is also recommended.

How the work is organised

Work starts with a site visit to confirm borehole locations, rig access, underground utilities and adjacent buildings. In central Baku, narrow streets, courtyards and traffic restrictions often call for compact drilling rigs, and work is scheduled for hours when it causes the least disturbance to residents.

Undisturbed samples are packed to preserve their natural moisture and structure and delivered to the laboratory promptly; within the city this is usually possible on the same day. The price depends less on distance than on access difficulty, the number and depth of boreholes, the thickness of fill and the scope of additional testing. An exact price is calculated from the technical brief and site location plan — you can send a quote request.