SU99613A1 - Installation for determining the resistance to compression and shear of soil samples under conditions of a complex stress state - Google Patents

Description

The subject of the invention is an installation for determining the properties of soils with the Compression of compression and displacement under the conditions of a collapsed flat state, based on the use of a winding twist of the test sample of a cylindrical soil sample placed in a thin rubber shell between the inner and outer chambers, water, where the sample is exposed to external and internal hydraulic pressure by the compressor.

The known devices of this type for complex testing of soil samples and, in particular, for determining the modulus of their elasticity, have the disadvantage that they allow leakage of fluid from the outer chamber and do not eliminate distortion, its effect of friction in oil seals on the accuracy of the instrument readings.

In the proposed device, the indicated drawbacks are eliminated by the fact that the traction device for tightening the soil sample studied is equipped with a Double stuffing box with a separating chamber, in which the air is generated by means of a compressor equal to the pressure of the water in the outer working chamber. In addition, the axis of the traction device is equipped with a fork, 1 which, when the axis rotates, rests on the tides on the upper and tampus. close the investigated soil sample.

In the drawing, pzo-brazhena proposed installation.

The working cavity of the installation consists of an outer chamber / and an inner chamber 2. The wall of the cavity is made of plexiglass. Sample 3 of the soil under study has the shape of a hollow cylinder and is enclosed on the outside and inside in a thin rubber shell. The bottom stamp on which they sample is provided with ribs and fastened directly to the bottom of the working chamber. Through the bottom n lower shtamp to the soil sample, vacuum lines 4 are installed.

If necessary, according to the test conditions, the sample is saturated with water from the bottle 5. A vacuum is required to form sandy soil samples by means of a pump 6. Vacuum is measured with a vacuum meter 7. Water is filled into the inside of the working cavity with the help of line 8. Water is measured in This line is produced by means of a burette 9, and pressure is created by means of a compressor (not shown in the drawing), in series with which the BKviro4eH expansion tank 10, equipped with a 1 / W meter. Water is first poured into the inner chamber, and then the outer chamber. In this case, the inflatable chamber is filled with water by means of the burette J2, which also serves to measure volume changes in the outer chamber. Air from the chamber is released through the faucet.

The cover J4 of the inner chamber is mounted on the axis 5 and is equipped with a bearing 16. The cover can rotate following the upper die 17 mounted on the sample under study. The upper die is provided with a tide against which the plug 18 transmits the torque generated by the traction device (not shown in the drawing) connected by a cable 19 with the axis of the plug. In order to exclude from the instrument readings the force of friction of the fork axis in the gland 20, the fork is not connected directly to the upper die, but only abuts against the tides present on it.

Since water leakage from the outer chamber can lead to obviously erroneous readings of the burette, the plug axle oil seal is doubled with a separating chamber 21. In the chamber, through the air pipe 22 from the compressor, through the expansion tank 23 with a pressure gauge 24, a pneumatic pressure is created in the chamber outdoor camera. Thanks to such a device

device gland works with almost zero differential pressure. Some air leakage through the upper gland does not have a noticeable effect on the measurement results in the process of examining the soil sample.

The process of determining the resistance to compression and shear of the soil samples studied using the instrument consists in that an external pressure P is applied to a soil sample having the shape of a hollow cylinder by means of a compressor through an external chamber and an internal pressure P as well as through the internal chamber. dry time: specified by traction device.

P eedient of invention

Claims (2)

1. An installation for determining the resistance to compression and shear of soil samples under conditions of a complex stress state, based on the application of a method of tightening a hollow cylindrical soil sample enclosed in a rubber casing, placed between the water filled in and the outer chambers and subjected to testing the external and internal hydraulic pressure carried out by the compressor, as well as tightening by means of a cable pull device, characterized in that neither leakage of water from the outer working chamber, a driving device is provided with a double gland seal with the separation chamber, in which fed air pressure equal to the pressure in the outer gidravlichesko.mu working chamber. 2. The device according to claim 1, wherein it is designed so that, in order to eliminate the distorting effect of friction in the glands, the axis of the traction device is provided with a fork abutting during the rotation of the tides on the upper stamp closing the soil sample under study.