10 kV cable lines, Prospekt Vernadskogo (Moscow)
Three types of surveys for the diversion of six 10 kV cable lines with two trenchless HDD crossings at depths of up to 14 m beneath Prospekt Vernadskogo and Ulitsa Koshtoyantsa.
Objective
We completed geotechnical, environmental and hydrometeorological surveys for the reconstruction of six 10 kV cable lines between transformer and distribution substations on Vernadskogo Avenue — the lines are being rerouted to clear a site for development. The client is an electricity grid company; the works took place in February–April 2025 under two contracts.
The 162.6 m route runs through the densely built-up Troparyovo-Nikulino district: cables are laid in ducts via two trenchless horizontal directional drilling (HDD) crossings measuring 110–120 m in length at depths of up to 10.5 and 13.8 m, with the remainder laid by open cut in a trench. Boreholes and sounding points had to be positioned in congested conditions among live utilities and within the carriageway.
Three boreholes 15 and 17 m deep were drilled using a URB-2A-2 rig by core drilling with full core recovery and casing support, accompanied by cone penetration testing (CPT) at three adjacent points. Soil strength and deformability were determined in the laboratory using triaxial compression and direct shear tests.
Scope of work and deliverables
GTGeotechnical surveys
Scope of work
- 3 boreholes 15 and 17 m deep — 49 linear metres of cased 127 mm rotary core drilling
- 3 cone penetration tests (CPT) to the depth of the HDD crossings
- sampling of 31 undisturbed cohesive soil cores, 9 soil samples and 3 groundwater samples for corrosivity testing
- laboratory testing: physical properties on 31 samples, 18 triaxial compression tests and 12 direct shear tests
- hydrogeological observations in boreholes, horizontal and vertical survey control of exploratory points
Results
- Geotechnical conditions — complexity category II (medium); plot on a gently sloping fluvioglacial plain with elevations of 177.1–179.0 m.
- From the surface lies a thick layer of made ground (4.2–4.9 m) — consolidated clay loam with crushed stone, brick, and concrete inclusions (EGU-1, deformation modulus 19 MPa); below to 8.4–11.9 m is stiff fluvioglacial clay loam with sand interbeds (EGU-2, 17 MPa), underlain by moraine clay loam with crushed stone and gravel (EGU-3, 22 MPa), through which the HDD crossings will pass.
- The supramorainic aquifer was encountered at a depth of 6.3–8.7 m, with moraine loams acting as the aquiclude; the HDD crossing route runs below the groundwater table, so dewatering is recommended during construction.
- Soils are non-aggressive to concrete, but highly aggressive to carbon steel — protection of metal elements is required.
- Standard frost penetration depth is 1.59 m, with low frost susceptibility in the made ground; the site lies outside karst hazard zones according to Mosgorgeotrest maps.
- EGU-1 Made ground: consolidated brown stiff loam with crushed stone, brick and concrete fragments, and interbeds of silty sand (tQIV)
- EGU-2 Yellowish-brown sandy clay, stiff, with interbeds of saturated sand and plastic silty sand, with pebbles and gravel, fluvioglacial and glaciolacustrine (f,lgQIIms)
- EGU-3 Dark brown sandy clay, stiff, with interbeds of very stiff sandy clay and fine sand, with crushed rock and gravel up to 25%, glacial till (gQIdn)
- Groundwater level
Legend
- geotechnical borehole, number and depth, m
- cone penetration test (CPT) point, number
- geotechnical cross-section line, number
- route of proposed cable lines
ESEnvironmental surveys
Scope of work
- 6 topsoil and subsoil samples to a depth of 2 m: heavy metals, petroleum hydrocarbons, benzo(a)pyrene; 2 samples each for microbiological and parasitological indicators
- reconnaissance gamma survey of 0.1 ha, gamma dose rate measurement at 5 control points, 6 samples for radionuclide content
- interpretation of satellite imagery, 0.3 km reconnaissance survey, enquiries to regulatory authorities, schematic map of environmental conditions
Results
- Soils and ground down to 2 m fall into the 'permissible' contamination category and are 'clean' by microbiological and parasitological indicators; unrestricted use is permitted.
- The radiation environment is normal: no anomalies, and soils belong to Class I by effective specific activity of radionuclides.
- Background concentrations of pollutants in ambient air do not exceed the MPC.
HMHydrometeorological surveys
Scope of work
- plot climatic summary based on the nearest weather station: design and standard temperatures, precipitation, wind, snow and ice loads
- Roshydromet certificate on hazardous hydrometeorological phenomena in the area
- assessment of surface water impact on the cable 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 three technical reports for the design of cable line diversions and HDD crossings. A positive non-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.