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tioally in the tom. ot graphs*

Fig*3* Static sounding apparatua S-832

The meohanl8oi for sorewing piles is driyen by the truck engine.

THE TBCHNICAL OHARACTERIS TI03 OF

8-832:

Depth of penetration up to m - 13 MaadJam driying f orce kg -10000 Maxlmum point load    kg    - 7000

Marimum ratę of penetration    m/min    - 3

Besides these two apparatua with the cone of 10 om² area there i a the combined rig for static sounding and a radioacti-ve inyestigation, developed by the ins-titute 'Wsegingeo". The rig consista of two truck-mounted apparatua: one for pressing down measuring sounding tubea and another for the prooeasing of the data obtained by the measuring sounding tubea.

The mftTlinnm depth of sounding is 23 m, the driying force-11₁8 t. The rig inclu-dea two measuring sounding tubea 62 ma O.D. The point resistance and the skin friotion on the aleeye oan be meaaured by this apparatua and the bulk density and the moisture of soils - by the radio-aotiye methods.

3* TEST PROCEDURĘ

As a rulet penetration test&ar* uaed together with the engineering and geologi-oal inyestigations of soils*

Dynamie sounding i a madę by the appa-ratus UBP-15 without bo ring. The direct result of the test is the number of blows and the depth of penetration correspon-ding to thia number of blows. The depth of penetration is measured with the acou-racy +0.5 o®* Up to 1973 the number of blows to driye the oone 10 cm into the soil (Nio) haa been the main parameter of the dynamie sounding* The real number of blows had to be correoted depend-ing on the depth of penetration* When the depth of penetration yaried from

0    to 20 i, the oorrection ooefficient ehanged from I to 0*42* Since 1973» the resuita of the dynamie sounding are eva-luated by "conditional dynamie reais-tance", ezpressed in kg/cm² and determi-ned by the formula:

p _ aua__    (l)

where k - coeffioient acoounting for

the losa of energy c£ a blow with the depth and ranging from 0*63 to 0*49 when depth is changing from 0 to 20 m;

U - coeffioient for the equipment uaed, being equal to the weight of a hammer multiplied by the heŁght of its fali and diyided by the area of the cone. For the main hammer H is 112 kg/om²;

i - coeffioient taking into ac-count soil friotion on sounding tubę,being within 1 to 0*6;

n - number of blows)

h - penetration for a glyen number of blows in cm*

Diagrams of sounding are recosmended to combine with the engineering and geo-logical profile and to dra w: the depth of penetration - on the ordinate azls on a scalę of 1 omal m, conditional dynamie resistance (pa) in kg/cm2 - on the abscissa on a scalę 1 cm=20 kg/cm², correoted numbers of blows (Nio)- on a scalę 1 om = £ blows*

In static sounding point resistance (q) and the total resistance along the sounding tubę (or the sleeye) are measured every 20 cm of penetration or recor-ded automatically.

The sounding i8 carried out by simul-taneous puahing of sounding tubea and point and making readings or recording* For the determining of properties af soils and the bearing oapaoity of piles the ratę of penetration ahould not ex-oeed 0.3 m per min.

The graphs of sounding are recommanded to combine with the engineering and geo-logical profiles and to draw: the dopth of penetration - on the ordinate azis on a scalę 1 om - 1 mj the specifio point resistance (q) in kg/om²- on the abscissa on a scalę 1 cm-20 kg/om²; the total skin friotion on a tubę - ^ in t on a scalę 1 cm-0*5 t, or the specific frię-tion on a sleeye (f) in t/m^{2 011} a scalę

1    cm -1 t/m².

4. INTERPRETATIOR OF TEST RESULTS

The State of the science of soil mechanice has not yet proyided the theore-tical solution that might be uaed for determining the properties of soils by the data of sounding. Many próbiems of the theory of ultimate eąuilibrium are solyed by the soviet scientists (Sokolovksy-Berezantzey), including the azlsymmetri-cal problem of penetrating a sounding tu-