An exclusive 14-storey apart- ment house with three-level underground parking space was constructed by the Italian firm “CODEST International S.R.L.” at 4, Kapranov Lane in Moscow under narrow conditions on a hill-side with steep-drop marks to 4 m over the buried preglacial erosive incut. 1-3.5 m – layer of sandy- clayey fill-up soil including con- struction waste; 4.5-5.7 m – layer of coarse and semi-coarse sands with gra- vel, of middle consistence; 6.5-10.6 m – layer of loamy soils with sand seams and gra- vel, semisolid, hard-plastic and soft-plastic; 1.7-3.4 m – layer of plastic sandy-clay; 1.9-2.7 m – layer of silt solid sands, with gravel here and the- re; 5.5-12 m – layer of coarse and semi-coarse sands with gra- vel, solid;

to 8.5.m – layer of eroded to blocks, crushed stone and powder Perkhurovsky karst limestones;

underlying stratum of marly clays with seams of limestone and marl, hard.

Prior to the beginning of construction the level of underground waters was detected at 1-3 m below the bed of the foundation slab in the base of which there are hard-plastic loams with seams of sand and gravel as well as plastic sandy-clays. In due course the underground waters rise up to the foundation plate top level is predicted.

Due to the absence of a waterproof layer over the stratum of eroded Perkhurovsky limestones and presence of underground waters pressure difference the construction site is considered to be potentially dangerous in the karst- suffusion aspect.

To escape the bentonite slurry losses after the planning soil cutting off on the construction site before the erection of diaphragm walls and deep foundations the preliminary cement-bentonite plugging of Perkhurovsky karst-limestone roof under their bases was executed. The plugging was made with hydraulic boring rig HBM15 for the depth of 2 m from the limestone roof or 2 m deeper of the drilling fluid first loss. In case if the grout consumption necessary for the plugging of holes with a 2 m step was exceeding 3 m³, additional plugging holes with a 1 m the general step were drilled between them. Grout injection was executed through the metal pipes of 114 mm diameter under the pressure of 2.5 bar, depending on the grout fall in the injection pipe different grout compositions were used. To reduce the losses the sodium silicate was added into cement-bentonite grout.

In-situ reinforced concrete bearing diaphragm walls of 60 cm thickness and up to 21.5 m depth with the total area of 1849 m² were used being both the excavation enclosure and at the same time bearing structures and watertight diaphragms.

Diaphragm walls were constructed by application of hydraulic grab equipment by technology developed by French company "SOLETANCHE BACHY", providing for sealing of joints between panels by "Waterstops" (Fragment of preliminary panel with "Waterstop" waterproofing gasket after removal of "Stopsol" stopend.). Trenches excavating was made under the protection of bentonite slurry by the up to 5.6 m long portions. The quality of joints between diaphragm walls was secured due to using of L-shaped corner portions. High quality of joints between panels (to exclude any mud joints) was ensured by removable stopends ("Stopsol") of preliminary trench portions, as well as by preliminary excavation of secondary and following portions until removed. In order to ensure mutual deformation of zero cycle structural elements in the diaphragm walls it was provided to leave longitudinal grooves in joints between foundation slab and floor-slabs. Grooves in diaphragm walls were formed by filling the required zones of reinforcing cages with polystyrene foam blocks, covered in PE film t=0.16 mm and fixed to working reinforcement by metal wire. The deep foundations, of 60 cm thick, are executed from the same working level with diaphragm walls from the foundation slab bottom to the Perkhurovsky limestone roof that cannot be developed by a grab either for the depth up to 20.5 m relative to the working level or for 12.6 m depth relative to the foundation slab bottom. Their erection was carried out parallel with the diaphragm walls construction. Four T-like deep foundations have overall dimensions 2.7x2.7 m, three T-like deep foundations – from 2.7x4.6 m to 2.7x6.24 m, one of the foundations is of a rectangular cross-section of 2.7x0.6 m.

To prevent a initiation of karst-suffusion processes in the base of exclusive apartment house a cementation of Perkhurovsky karst limestones stratum from the bases of diaphragm walls panels and deep foundations to the roof of lying bellow waterproof marly-clays was made after the completion of diaphragm walls and deep foundations erection through the metal pipes with 114 mm diameter had been laid during their construction.

Drilling workings was done applying the rig HBM15 and the cement grout injection under the pressure 2.5 bar with the pump PH125C. Initially the grout with water-to-cement ratio W/C = 0.8 of 400 l volume has being injected and then in case of pressure drop during 10 minutes – with W/C = 0.5-0.6 – to the full. Sodium silicate was added into grout to decrease its consumption. Thus, the watertight curtain in the diaphragm walls base around the building zero cycle was practically executed as well as cementing consolidation of eroded Perkhurovsky limestones, the caverns under the deep foundations and diaphragm walls were eliminated.

Ground excavation was carried out under the protection of one-level temporary metal support which included four knee braces made of 530 mm diameter pipes, one intermediate bunton made of 820 mm diameter pipe and the belt made of the coupled flange beams №40 Б1.

Small dimensions of enclosure and excavation pit depth have determined strongly pronounced spatial character of diaphragm walls operation that was confirmed by appropriate calculations.


To reduce the 14-storey building-tower zero cycle constructional elements settlement difference caused by irregularity of loading and complexity of geological conditions the deep foundations and diaphragm walls were jointed by the foundation slab of 60 cm thickness. The slab had the thickness up to 78 cm over the deep foundations.

The diaphragm walls were connected to the foundation slab by means of ~12 cm deep grooves and two tiers of bar glued anchor stays HILTY (HIT-HY 150) in diameter 25 A-III with a 400 mm step.

The foundation slab waterproofing was executed applying the bentonite mats Voltex, connection joints of the foundation slab with deep foundations and diaphragm walls are additionally condensed with the help of bentonite-rubber hydro-gasket “Red stop”.

As the diaphragm walls were constructed under the special technology of the company "SOLETANCHE BACHY" applying joint condensing between the panels with the waterproofing tapes of "Waterstop" type, the walls waterproofing was not envisaged. Insufficient local water penetration through the wall defects were removed by the caulk using the compositions with noncontracting or self-stressing cement and along the panel body – by the injection of polymeric pitch “CARBOSTOP W” (“CARBO Add X (Y)”) or “CARBOPUR WFA 16 – BEVEDAN” by the firm CarboTech Fosroc Gmbh. production.

The in-situ reinforced concrete floor-slabs with the thickness of 30 cm (under the pool – of 40 cm thick) are made plane and girderless and supported by the diaphragm walls with grooves of about 16 cm deep.

The structures of the zero cycle were designed using the 3D-calculation scheme with consideration of loading due to 14-storey aboveground part of building.

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