METHOD OF MEASUREMENT OF IN SITU CHARACTERISTICS OF SOIL WITH ITS WETTING (VERSIONS) AND GEAR FOR ITS IMPLEMENTATION

摘要

FIELD: engineering geology. SUBSTANCE: method is meant for examination of mechanical properties of swelling soils. It consists in lowering of expanding probe into borehole made in soil, in creation of starting pressure Po on soil equal in value to natural one and in supply of liquid into soil for wetting. In compliance with first version liquid is supplied under pressure of several meters of column of this liquid. After soil wetting pressure on soil is increased by regulation of volume of probe V const till soil os saturated with liquid. Swelling pressure V=const is calculated by difference of final Pk and starting Po pressures. Then decreasing Pk to Po by regulation of volume of probe from starting Vo to final Vk one calculates volume of soil expansion by their difference with swelling δV. In agreement with second version after supply of liquid into soil one controls pressure P created with probe on to soil keeping P=Po=const by decreasing volume of probe from Vo to Vk till soil is saturated with liquid. Then δV_n=Vo-Vk is determined. After this δP_n is found by increasing Po to Pk controlling volume of probe from Vk to Vo. δP_n=Pk-Po. Water is used as wetting liquid. Gear for implementation of method has expanding probe with means for formation of radial pressure, supply of liquid into soil and measurement of V and P. Probe is manufactured of at least two parts having independent means for control and measurement of radial pressure. One of independently expanding parts of probe is coupled to means for supply of liquid into soil under pressure. Parts of probe can be superimposed one on other. Probe can also be fabricated of four expanding sectors joined in pairs in opposition to conduct measurements in one and same layer. EFFECT: improved reliability of method. 10 cl, 6 dwg