Range of adjustment, degree + l ＜30'
Method of lifting guide column Hydraulic
lift of guide column, m 0.6
Overall dimensions at working position, m
height 19. l
width 3.15
length 9.03
Specific pressure on soil, kPa 12
The NOVK-8/14 consists of the following: guide column; cap; hinged joint, suspension; mechanism tbr directing the stamper on to the tbundation pit axis; rear carriage; circular sling; rammer with carriage; gripping device; ail station; column lifting hydraulic cylinder.
The guide column is a box-like structure fabricated out of slotted l-beam and consists of the bottom and top parts connected by means of flanges. Three hinged brackets are provided on the column for releasing the rammer from 7, 9, and 14 m heights. At the bottom, the column is connected with the base by means of a ball pivot, and at the top is the cap with branch blocks.
The suspension is fitted in place of the jib cap of crane RDK-250. The guide column is mounted on the suspension by means of the hinged joint.
The directing mechanism is designed in the form of a telescopic pipe with hydraulic cylinders tbr longitudinal and transverse swinging of the guide column. At one end, it is hinge jointed with the moving part of the base machine and, at the other (which terminates in a yoke), with the guide column by means of runners. The column lifting hydraulic cylinder is fitted
on the yoke and is secured to it by means of the cylinder rod. The yoke is connected with the hinged joint with a circular sling. Therefore, when the hydraulic cylinder rod moves out, the circular sling is pulled up and the column moves upward relative to the runners of the yoke and the hinged joint.
The stamper is fabricated out of steel plates and is filled with concrete for making up the required weight. It is hinged jointed with the carriage. A damping device is fitted between the carriage and stamper. The carriage along with the stamp moves on rollers relative to the column and is retained in the column by means of renewable stops which can be replaced as
they wear out. Deviation of the stamp center from the would-be tbundation pit is not more than 3 cm and angle of turn of the axes is not more than 5 ＜ 14l.
The gripping device is meant tbr coupling the carriage with the stamper, lifting them upward by the winch of the base machine, and automatically releasing them after the required height is attained. The rear carriage is tbr selecting the cable tbr
changing the ratio of the block-and-tackle.
The hydraulic cylinders are operated from the additional oil station which includes a hydraulic tank, pump, and asynchronous motor. Hydraulic fluid distribution and safety equipments and HP hoses tbrm part of the hydraulic equipment. Approximate cost of fabrication of the equipment is 25' 103 rubles. Sate life of the mounted equipment till major
overhaul is 7000 motor h. Operation of the equipment with the use of erecting crane RDK-250 as the base machine is effective only in case of large volume of works at the same site since considerable labor is involved in moving the equipment from site to site. In this connection, the NOVK-6112 mounted on the type I~O-511B rope-and-pulley excavator is more expedient (Fig.
1).
Specifications of NOVK-6/12
Base machine Type I~O-51 IB excavator
Stamper weight, tons 6
Stamper height, m 3
Diameter of circle circumscribe by stamper, m
by the top part i.3
by the bottom part 0.6
Maximum height of release, m 12
Maximum energy of impact, kJ 705
Maximum withdrawing force, kN 368
Maximum pressure in hydraulic system, MPa 32
Method of adjusting vertical position of column Hydraulic
Range of adjustment 5: I ＜30'
Method of lifting guide column Hydraulic
Lift of guide column, m 0.6
Overall dimensions in working position, m
height 16.5
width 3.1
length 10.3
Specific pressure on soil, kPa 118
The mounted equipment of the NOVK-6/12 consists of following main units: guide and bearing columns; hinged joint; directing mechanism; column lifting mechanism; stamper with carriage; gripping device of hydraulic equipment.
Unlike NOVK-8/14, this equipment is equipped with an original hydraulic mechanism for extracting the stamper from the soil. This mechanism is built in at the bottom part of the column and consists of a series of slip hooks located on a push rod which is moved along the guide column by means of the hydraulic cylinder (Fig. 2). With advancement of the hydraulic
cylinder rod, the slip hooks are positioned horizontally and one of these gets engaged with a catch on the carriage and pulls the stamper out of the soil. Further, the stamper is lifted by the winch of the base machine.
The proposed stamper extraction mechanism facilitates the elimination of high loads acting on the guide column thereby reducing its metal content. Moreover, the ratio of the block-and-tackle is reduced to the value required for lifting the stamp.
The bearing column used instead of the boom of the base machine is fabricated out of 76 mm diameter metallic pipes and is meant for suspending the column and transferring to the base machine the loads occurring during operation of the equipment and maneuvering of the machine over the construction site.
The hydraulic equipment includes the hydraulic drive operated from the power take-off shaft of the base machine, control panel, and hydraulic fluid distribution hoses.
The approximate cost of the equipment is 27.103 rubles.
Since a rammer of not more than 6 tons is used in NOVK-6/12, this being not always adequate for laying foundations of industrial buildings, its design was modified and the NOVK-1 developed. This is mounted on type I~O-511B and I~-1252B excavators or type RDK-250, MKG-25BR, etc., erecting cranes. Use of the independent bearing column facilitates mounting of the NOVK- 1 on different base machines. For this, an intermediate beam with brackets is used. The brackets are for fixing one side of the beam to the moving part of the base machine and the other to the bearing column. Moreover, the base machine
is equipped with an independent hydraulic drive which in excavators is driven by the power take-off shaft of the diesel engine and, in diesel-electric cranes, by a generator.
These equipment are provided with changeable stampers of different contigurations. Pyramid-shape stampers are fabricated out of 16-36 mm thick steel plates and are meant tbr ramming down up to 4 m deep foundation pits. Cylindrical stampers are fabricated out of thick-walled metallic pipes with end pieces 1.2-2 times larger in diameter than the pipe. These
are meant for driving pileholes of up to 7 m depth and 0.8-m diameter.
These mounted equipment for ramming down foundation pits have been introduced in construction works undertaken by the State Construction Committee of the Kazakhstan SSR.
The NOVK-I was used in Temirtau Kargandinsk District in erecting nine-story 72-flat and five-story 87-flat houses
of the 121 series.
The construction site was composed of difficulty plastic water-saturated loamy and clayey soils of solid and semisolid consistency ~d = 1.66 g/cm3; E = 10 MPa). The foundation pits were rammed down to depths ranging tbrm 2.2 to 2.5 m. From 6 to 10 impacts from 9 m height were required for ramming with the use of a 6 ton stamper. To increase the load
carrying capacity, rubble in 0.25 m 3 portions was rammed in into the pit bottom.
The load-carrying capacity of foundations after ramming in rubble of 0.5-1.5 m 3 volume was 700-1200 kN.
Fig. 1. Mounted equipment for ramming down foundation pits.
.7
Fig. 2. Hydraulic mechanism for extracting stamper from
the soil: 1) guide column; 2) push rod; 3) slip hook; 4)
hydraulic cylinder; 5) catch; 6) carriage; 7) stamper.
A five-story 144-flat building was erected in Kustanae on toundations laid in rammed down pits. The construction site
of the dwelling house was composed of up to 1.8 m thick subsiding, type I, sandy loam soil (Pd = 1.6 g/cm3; E = 24 MPa).
Underlying this was clay of semisolid to softly plastic consistency.
The foundation pits were rammed down to 2 m depth using a 6 ton stamper released from 9-m height. Six to eight
impacts were required for each pit. Rubble in 0.25 m 3 portions was rammed in into the pit bottom to raise the load-carrying
capacity. From 2 to 6 stamper impacts were required for ramming in the rubble portions. After ramming in 0.5 and i m 3 in
volume rubble, the load-carrying capacity of the foundations was 860 and 1170 kN.
Pile foundations rammed into driven pileholes were introduced in Leninogorsk in the West Kazakhstan region. A
cylindrical punch-stamper of 4 ton mass and 6 m height having a 0.6-m-diameter tear-shaped endpiece was used for driving
the pileholes. The construction site was composed of 6-7 m thick subsiding, type 1, loamy clay (Pd = 1.45 g/cm3; E = 4 MPa)
below which lay nonsubsiding loamy clay. Underlying the latter to 12-15 m depth was gravelly and coarse gravel deposits. The
punch was released from 6 m height. A single pilehole required 15-25 impacts of the punch. After ramming in three portions
of rubble (total volume of 1 m3), the load-carrying capacity of the foundation was 1170 kN. Two five-story 69-flat block-
sections for small families, and a five-story 120-flat dwelling house, were erected on these pile toundations rammed into driven
pileholes.
Foundatir~rts laid in rammed down pits and driven pileholes in 1989 was 10' 103 m 3 in volume with total economic effect
of 300" 103 rubles.
Fabrication of the mounted equipment has been taken up in the experimental-mechanical plant of the SDO
"Soyuzspetsfundamentstroi ".
LITERATURE CITED
I.
V. I. Krutov, "Ways to further develop foundations in rammed down foundation pits," Tr. All-Union Scientific
Research Institute of Foundations, 1, 80-85 (1987).
"9
V. T. Antonyuk, "Improvement in technology of ramming down foundation pits of agricultural buildings," Author's
Abstract of Dissertation for Candidate of Technical Sciences, Kiev (1986).
3.
V. I. BykCw and N. K. Ivanov, "Further on techniques of ramming down foundation pit,K," Mekh. Stroit., N♂~. 3, 14-16
(1987).
4.
Handbook of Design and Laying of Foundations in Rammed Down Foundation Pits lin Russian], Stroiizdat, Moscow
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