SU211849A1 - DEVICE FOR DETERMINATION OF STRENGTH - Google Patents

Description

The invention relates to instruments for determining the strength and deformability of soils under conditions of triaxial compression.

A device of the same purpose is known, comprising a housing with an elastic shell inside it with a test soil sample, a hydraulic actuator and measuring equipment.

However, it does not provide the possibility of testing the ground at three unequal main stresses.

In order to eliminate this drawback, the body of the proposed device is made up of channel-shaped blocks, forming cavity-facing parts of each other, separated by elastic shell elements into an isolated space in the form of a cube for the soil sample and compartments for compressing the soil sample of the working fluid from all sides. Choy in them from the hydraulic drive through the channels of the block.

The drawing shows schematically the proposed device.

The device includes a body made of blocks / having channels 2. The parts facing each other form a cavity, which is divided by elements of the elastic shell 3 into an isolated space 4 3 shaped like a cube for the soil sample and compartments 5

for compressing from all sides the soil sample of the working fluid.

The channels of the blocks are connected to metal tubes 6, which connect the opposite sections in pairs with calibrated tubes 7 made from barometric glass, which fix linear deformations of the test specimen. The device also contains taps 8, blocking the flow of fluid from the calibrated tubes into the compartments; compensation tanks 9, from which compressed air is supplied to the calibrated tubes; taps 10, regulating the air pressure in the tanks 9, and the spotters}}, blocking the supply of compressed

air into calibrated tubes, as well as measuring apparatus 12 for measuring pressures transmitted to the soil sample. The device works as follows. When testing sandy soils, the estimated volume of the space 4 for the sample of the test soil is established. The level of fluid in the calibrated tubes 7 f xirat. Close the taps 8, remove the upper compartment 5 and into the space 4

the studied soil is filled up in the necessary volume.

the shells 3 bend inside the compartments and do not prevent the soil being tested from being immersed in the sample cavity.

During the testing of the soil at three unequal voltages, the taps 10-11 are closed and in the compensation tanks 9 a design pressure of the appropriate degree is created. After that, the taps // are opened, and the compressed air enters the calibrated tubes 7.

Measuring apparatus 12 measures the pressure transmitted to the sample. Under the action of compressed air, the liquid through the metal tubes 6 and channels 2 enters the compartments 5. The amount of liquid liquid received is determined by the change in its level in the calibrated tubes 7. By measuring the change in the volume of the compartments, the magnitude of the linear deformations of the samples can be determined.

The device makes it possible to determine the strength and deformability of soils under conditions of three-axis stress, the sum of the principal stresses and the variable stress intensity, as well as the constant sum of the principal stresses and the variable direction of the octahedral stress vector in the axes of the main stresses.

Thus, the proposed device allows testing the ground at unequal main voltages.

In addition, the device allows for hydrostatic compression of samples, testing of samples at constant lateral pressure, and can also be used according to the operation scheme of the odometer and according to the open and closed experimental schemes when testing water-saturated soils.

Subject invention

A device for determining the strength and deformability of soils under three-axis compression conditions, including a case with an elastic shell placed inside it with a test soil sample, hydraulic actuator and measuring equipment, characterized in that in order to enable soil testing at three unequal main stresses , the device body is made up of channel-shaped blocks forming parts of a cavity facing each other, separated by elements of an elastic shell into an isolated cube-shaped space for samples ground and the compartments for compressing all sides sample soil working fluid supplied from the hydraulic drive them through the block channels.

Jz

2

0 „

ABOUT