Badania osadów bagiennych statyczną sondą wkręcaną typu Viktsond

Marian Perek

Abstract


Przedstawiono wynikł badań właściwości fizyczno-mechanicznych namułów i piasków pochodzenia bagiennego za pomocą statycznej sondy wkręcanej typu Viktsond, sondy obrotowej, lekkiej sondy stożkowej i metod laboratoryjnych. Drogą obliczeń statystycznych porównano wyniki poszczególnych sondowań, uzyskując dla niektórych zależności korelacyjne. Opisano również wyniki nowego sposobu sondowania sondą wkręcaną typu Viktsond przy zmniejszonym o 50% obciążeniu statycznym. Ze względu na specyfikę strukturalną namułów badania laboratoryjne właściwości fizyczno-mechanicznych tych gruntów dały wyniki nieporównywalne pomiędzy poszczególnymi parametrami.

ON THE STUDIES OF SWAMP DEPOSITS WITH THE USE OF STATIC SOUND OF THE VIKTSOND TYPE

Traditional research methods not always allow for appropriate evaluation of carrying capacity of soft foundation soils of alluvial and swampy origin. The paper presents the results of studies of silts and sands of swampy origin, carried out with the use of static sound of the Viktsond type and rotary and light conical sounds. The silts were also covered by laboratory studies but the scattering of the results obtained was too large for tracing any depondence between static loading of the Viktsond sound and physico-mechanical parameters such as naturai moisture, degree of plasticity, volume weight and modulus of original compressibility.

The interdependence between static loading of the Viktsond sound and maximum strength to shearing by rotary sound was established for silts (Fig. 5). The correlation coefficient obtained for this interdependence of equal 0.78.

The sound of the Viktsond type weighs about 200 kg so there are serious difficulties with transportation of its elements by means of man power, in boggy areas or on steeply inclined slopes. In connection with this the soundings of fine-grained sands were carried out with the use of 50 kg static loading and halfrotations i.e. with 50% reduction of static loading. This was accompanied by talking measurements according to the obligatory procedure, that is under 100 kg load and with halfrotations of the sound. A comparison of the results of soundings made according to obligatory and simplified procedures made possible to obtain correlative dependence (conrelation coefficient r = 0.93) which is important for the use of the results obtained with sound of reduced weight (Fig. 8). It appeared not possible to find correlative dependence between the number of strokes of light conical sound and the number of halfrotations made using static sound of the Viktsond type, with either normal or reduced weight, in estimating the degree of compaction of fine-grained sands because of too large scattering of the results obtained (Fig. 9).


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