10 and 6 kV cable lines, Sokolniki Park (Moscow)
Three types of surveys for the construction of two transformer substations and 10 and 6 kV cable lines in Sokolniki Park — two 1.8 km routes with ten HDD crossings beneath park avenues, Sokolnichesky Val and the backfilled valley of the Putyaevsky Brook.
Objective
We completed geotechnical, environmental and hydrometeorological surveys for the construction of two transformer substations and cable lines: four 10 kV lines from the new TP-1 to tie-in points on existing cables, and two 6 kV lines from RTP-1750 to the new TP-2 in Sokolniki Park. The client is a design organisation working for an electricity grid company; the surveys were conducted in January–March 2025.
Both 1.8 km routes run through parkland and adjacent streets: installation is designed in open trenches and ten trenchless HDD crossings ranging from 57 to 296 m in length at depths of 2 to 13 m. The routes cross cultural heritage protection zones, and the northern section of the second route crosses the partially backfilled valley of the Putyaevsky Brook.
Twenty-six boreholes from 4 to 17 m deep were drilled using a URB-2A-2 rig by rotary core drilling with full core recovery and casing support, combined with cone penetration testing (CPT) at twelve locations. Sands were tested by triaxial compression; topsoil samples were collected along the route and a radiation survey was performed.
Scope of work and deliverables
GTGeotechnical surveys
Scope of work
- 26 boreholes 4–17 m deep — 316 linear metres of cased 127 mm rotary core drilling along two routes
- 12 cone penetration tests (CPT) along HDD crossing alignments
- sampling of 30 undisturbed cohesive soil cores, 54 disturbed sand samples, 24 soil samples and 6 groundwater samples for corrosivity testing
- laboratory testing: physical properties on 84 samples, triaxial compression of sands and sandy clays, direct shear
- groundwater level measurements in boreholes, reconnaissance survey of routes
Results
- Geotechnical conditions — complexity category II (medium); the first route lies on a gently undulating moraine plain with surface elevations of 147.7–152.9 m, and the second lies on an ancient alluvial terrace of the Yauza River at elevations of 144.0–147.7 m.
- Beneath made ground up to 2.5–4.1 m thick lie medium-dense fine sands (EGU-2, deformation modulus 21–25 MPa), underlain by soft sandy clays with water-saturated sand interlayers (EGU-3, 13–17 MPa) and dense silty sands (EGU-4, 29 MPa).
- Groundwater was encountered at a depth of 1.5–4.3 m along the first route and 1.7–3.1 m along the second; the routes are waterlogged, and construction-phase dewatering is recommended.
- Groundwater is moderately aggressive to concrete; soils are non-aggressive to concrete but highly aggressive to carbon steel — steel elements require protection.
- Standard frost penetration depth is 1.59 m for made ground and 1.31 m for fine sands.
- EGU-1 Made ground: unconsolidated dark brown plastic sandy loam with sand and up to 20% construction debris (tQIV)
- EGU-2 Fine light-grey sand, medium dense, low saturation to saturated, with interlayers of silty sand and sandy silty clay, fluvioglacial (fQIIms)
- EGU-3 Dark brown sandy clay, firm, with interbeds of saturated sand, with crushed rock and grus up to 10%, glacial till (gQIId)
- EGU-4 Silty greenish-yellow sand, dense, saturated, fluvioglacial (fQIIo-d)
- Groundwater level
Legend
- geotechnical borehole, number and depth, m
- cone penetration test (CPT) point
- geotechnical cross-section line
- route of proposed cable lines and HDD crossings
ESEnvironmental surveys
Scope of work
- 10 topsoil and subsoil samples along the route to a depth of 1 m: heavy metals, petroleum hydrocarbons, benzo(a)pyrene; 2 samples each for microbiological and parasitological indicators
- reconnaissance gamma survey of 0.45 ha, gamma dose rate measurement at 5 control points, 10 samples for radionuclides
- interpretation of satellite imagery, 0.9 km reconnaissance survey, enquiries to authorised bodies, schematic map of environmental conditions, and map of zones with special conditions for land use (ZOUIT)
Results
- The surface soil layer at 0–0.2 m along the route falls into the 'hazardous' contamination category (restricted use with a clean soil cover of at least 0.5 m), while deeper soils are 'permissible'; by microbiological and parasitological indicators, the soils are 'clean'.
- The radiation environment is normal: no anomalies, and soils belong to Class I by effective specific activity of radionuclides.
- The routes pass through the grounds and protection zones of cultural heritage sites, development regulation zones and a sanitary protection zone — these restrictions are accounted for in the report.
HMHydrometeorological surveys
Scope of work
- area climatic summary based on weather station data: design and standard temperatures, precipitation, wind, snow and ice loads
- certificate on hazardous hydrometeorological phenomena
- assessment of the hydrological regime of surface water bodies and the culverted/backfilled Putyaevsky Brook along the route
Results
- A climatic characterisation with design and normative meteorological parameters was prepared for design purposes.
- A report on hazardous hydrometeorological events in the survey area was compiled.
Result
The client received sets of technical reports for two routes to design substations, cable lines and HDD crossings. A positive state expert review conclusion was obtained.
This is just one of our projects: every year our specialists carry out surveys on 40–50 sites in Moscow, the Moscow Region, and across Russia.
Send your technical brief — we will price it the same day
If you do not have a technical brief, describe the project: site location, planned construction, and whether a design exists. We will reply with a scope of work and cost.