Geotechnical Site Investigation in Sumgayit

Engineering geological conditions in Sumgayit

Sumgayit lies in the north-western part of the Absheron Peninsula on the Caspian shore. Most of the city occupies a low coastal plain sloping gently towards the sea; to the south and west the terrain rises gradually towards low hills. The Sumgayitchay valley runs to the north-west of the city. There are few steep slopes, so the main issues here relate not to topography but to soil composition and groundwater.

The coastal strip is dominated by Quaternary marine deposits: sands of various grain sizes, shelly sands and sandy loams with lenses of loam and clay. Further from the sea, older clays and shell limestone beds appear in the profile. Sand density varies with depth: loose sands occur near the surface and medium-dense sands deeper down.

The city grew as an industrial centre from the mid-20th century, so in and around the industrial zone the natural soils are covered by man-made deposits — construction and industrial waste, slag and remains of old foundations. The composition, thickness and chemical condition of these layers are not known in advance.

Key construction risks in Sumgayit

• Shallow groundwater. On the coastal plain the water table is shallow and fluctuates with the Caspian level, rainfall and leaks from urban networks. When basements and underground car parks are designed, dewatering of the excavation, waterproofing and drainage have to be resolved early.
• Aggressive groundwater. The influence of seawater and industrial contamination can make groundwater aggressive to concrete and steel. Without chemical analysis of water samples the foundation material and its protection cannot be selected correctly.
• Man-made and contaminated ground. Fill in the industrial zone may be both mechanically weak and chemically problematic. Additional sampling and chemical testing of the soil are recommended on such sites.
• Loose sands and seismic loading. Like the rest of the country, Sumgayit lies in a seismically active zone. Saturated loose sands can lose strength abruptly during an earthquake, so their density is checked by probing and site seismic conditions are assessed with the ground category in mind.
• Shoreline change. For structures right on the shoreline, wave erosion and fluctuations of the Caspian level have to be considered.

The water table matters for buildings without basements too: foundations and walls within the capillary rise zone stay permanently damp, and salts accumulating in the evaporation zone gradually destroy concrete and masonry. That is why waterproofing in Sumgayit is selected on the basis of the predicted maximum groundwater level and its chemistry, and the foundation concrete grade according to the aggressiveness indicators.

Surveys typically required

In Sumgayit the programme centres on groundwater and sand density. For residential and industrial buildings it usually includes:

• borehole drilling and sampling with measurement of encountered and stabilised groundwater levels;
• cone penetration testing (CPT) to assess sand density and pile capacity;
• aggressiveness of groundwater and soils and chemical analysis;
• for deep excavations, permeability tests to design the dewatering system;
• particle size distribution and other physical properties;
• shear-wave velocity from a seismic survey, including MASW;
• on industrial land, ground penetrating radar (GPR) and an underground utility survey to locate old services.

How the work is organised

The site visit confirms previous land use, existing wells and utilities, and a pad for the drilling rig. On an operating plant, work is coordinated with the site's access and safety rules, which affects the field schedule. If the plot borders active industrial facilities, additional soil samples for chemical analysis are included in the programme.

Undisturbed sampling is difficult in sandy profiles, so sand properties are determined mainly from probing and disturbed samples; undisturbed samples are taken from clay layers and delivered to the laboratory promptly. Sumgayit is close to Baku, so transport has little effect on the price. The cost is driven mainly by the number and depth of boreholes, the number of water samples and probing points, and site access. You can send the site location plan and technical brief via a quote request.