6585845015

Czechoslovakia 31

The need for special site inyestigationa in the East Sloyakian basin where thick depoaits of fine-grained water-eaturated sanda could not be examined by other teating methoda called forth a local introduction of penetration methoda. A relatiyely 8imple and light equipment for dynamie penetration te8ta waa con-atructed according to the deaign of the Koscow Research Institute for Founda-tiona and Underground Conatructions (NIIOPS). The diameter of the cone base waa 74 mm, cone angle 60 degrees, hammer weight 60 kp, ftee fali height 80 or 100 cm. The influence of wali friction i8 conaidered by using correcting empir-ical coefficienta when depth over 10 m ia achieyed.

In 1973 the National Corporation "Inieitfrako geologick^ a hydrogeolog! ck^ prtizkum, KoSice", which conducted tests in the Eaat Sloyakian area, haa imported an additional dynamie sounding eąuipment type BORROS. Besides the dynamie teating eąuipmenta the national Corporation in KoSice has uaed static penetration e-ąuipment system MAIHAK. This eąuipment with all nece88ary accesaories ia mount-ed on a two-wheel chassis and can be tranaferred by a four-wheel drive car. Additional counterweight against the penetration resiatance ia asaured by four aoil anchors. The penetration speed is in the rangę from O to 1.5 m/min; uaually the speed 0.25 m/min ia applied. Relatiyely good resulta were obtained during site inyestigationa on sand depoaits below water table and in the e-yaluation of bearing capacity ror pile foundations. A research work is under way in order to find correlation between the penetration resiatance and technical properties of soil depoaits in sorne low-land baaina in Sloyakia.

The Deaign Centre "Doprayoprojekt, Bra-tialava", has introduced dynamie sounding eąuipment type BORROS for the in-

spection of soil density in highway em-bankmenta and aome fili depoaits, for the determination of suitable foundation depth for bridge pierś and for the com-plement of site inyestigationa between regul8r boreholes. Research work ia under way to find out correlative rela-tions when uaing clasaical aoil mecha-nica teating procedurea.

In 1972 the Sloyakian Enterprise "Hydroconault" haa introduced the light sounding eąuipment BORROS with an auto-matic registration in order to inspect the sand density in the suction dredged dama.

The Technical Uniyersity, section Rail-way Transportation, in Żilina has used penetration methods sińce 1967 (M. Hol-zer) in order to determine the bearing capacity of the raiłway ballast base.

Referencea

BUKOVANSKf, M., 1958. Zprśva o prdzkumu poddolovańd trati u dołu EliSka v Chlum-ćanech - in czech (Report about aite in-yeatigation near EliSka minę in Chlumda-ny for a railway influenced by mining subaidance). Report Stayebnl geologie, Praha. No. 1749.

DROZD, K., 1964. Vliv promSnnd ylnkosti piaku na y^aledky dynamickć penetraćni zkouSky - in czech with english summary (The influence of yariable moisture con-tent in sand on the reaults of dynamie penetration test). Sboralk HIG. No. 1.

DROZD, K., 1965. The influence of yariable moisture content in sand on the reaults of dynamie penetration testa. Proc. 6th Int. Conf. Soil Mechanice Montreal, 3. 335 - 336*

DROZD, K., 1970. Discusaion to the dynamie penetration test - a standard that is not standardised. Geotechniąue. Vol. 20. No. 4.