SU889789A2 - Compression unit for determining deformation properties of solf - Google Patents

Description

(54) COMPRESSIONAL INSTALLATION FOR DETERMINING DEFORMATIVE PROPERTIES OF SOIL

I

The invention relates to construction, in particular, to a technique for determining the deformative properties of a soil under dynamic loads.

According to the main author. St. No. 571544 a known compression unit for determining the deformative properties of a soil, comprising a working chamber with perforated filters and a punch, a hydropulsator, a displacement sensor, a chip made of two parts with a membrane placed between them and equipped with a shaft passing through the working chamber, at the end of which displacements 1.

However, the design of such an installation does not allow lateral static and dynamic loads to be applied to the sample to be tested and direct measurement of lateral pressure to be made.

The aim of the invention is to expand the field of research and improve the reliability of the plant.

The goal is achieved by the fact that the compression unit for determining the deformative properties of the soil, containing a working chamber with perforated filters and a die, a hydropulsator, a sensor

displaced and shtamp, consisting of two parts with a membrane placed between them and provided with a rod passing through the working chamber, at the end of which a displacement sensor is installed, provided with an elastic cylindrical shell with plates placed with a gap inside the working chamber and attached to its ends, and the plates are attached to the inner surface of the cylindrical shell along its forming with a gap between them than the cavity of the gap between the cylindrical shell and the working chamber is hydraulically connected to the hydropulsator.

The possibility of direct application to the test sample of soil lateral static and dynamic loads

15 is provided by feeding into the side chamber, formed by the ring and the compressive elastic cylindrical shell, of the working fluid under pressure, which can be directly measured and recorded by any pressure sensor. Since the compressive elastic cylindrical shell is attached to the ring at the ends, in these areas the shell loses elasticity and, therefore, the transfer of lateral load to the soil sample becomes impossible without distortion in magnitude. To eliminate this drawback and increase the reliability of the proposed installation, as well as to protect the compressive elastic cylindrical shell from mechanical damage during the experiments and in preparation for them, a protective flange is attached to the compressive shell, vertical plates that are separated from the inner side of the shell another gap required to compensate for the change in the diameter of the side chamber during compression.

FIG. 1 shows a schematic of the proposed installation, the general view; in fig. 2 - working chamber, section.

The compression installation includes (see Fig. I) a platform 1, a working chamber 2 with a ring 3 and attached to it along the ends, which is located on the inner side with a compressive elastic cylindrical sheath 4. The last two elements 3 and 4 form a side chamber 5. A compressive elastic the cylindrical shell 4 is attached to the plate 6, which are separated from each other by a gap (see Fig. 2) and form a cylindrical surface, limiting the test sample of the soil 6 from the side. The protective flange 7 and the perforated filter 8 are located above, the perforated filter 9 is below. The stamp 10 located on the perforated filter 8, under which the ground 11 is placed, is made of two parts, between which the membrane 13 is rigidly fixed with screws 1.2, and provided with a rod 14 , at the end of which there is a displacement sensor 15, screwed onto the sleeve 16. The membrane 13 is pressed against the working chamber of 2 gi; A vacuum chamber 17 communicated by pipelines 18 and 19 with a hydropulse chamber 20. The load in chamber 17 is monitored by a sensor 21 and a pressure gauge 22, and in a chamber 5 by a sensor 23 and a pressure gauge 24.

Compression unit works as follows.

Dynamic load is applied to the test specimen of the grant along the side surface. In this case, the switchgear must be put in

a position where the hydropulsive 20 and the lateral 5 of the chamber communicate with each other. In this position, the fluid pulsation in the side chamber 5 is converted into vibrations by the compressive cylindrical elastic jacket 4 and, through the plates 6, transmits uniformly the height of the load on the soil sample. The amplitude of the dynamic load is recorded by a pressure sensor 23. Sample deformations in the horizontal

the direction from the lateral load causes deformations in the vertical direction, which are recorded by the displacement transducer 15. The pressure acting on the end of the specimen is recorded according to this test circuit using a pressure transducer 21.

The compression unit allows the lateral pressure in the test sample of the soil to be applied and measured when a static and dynamic load is applied to it, which greatly expands the possibilities of the installation. The use of the proposed compression unit allows one to more reliably and accurately determine the dynamic properties of soils, and therefore more accurately predict the amplitude of oscillations of the foundations for machines with dynamic loads.

Claims (1)

Invention Formula Compression unit for determining the deformative properties of the soil according to ed. St. No. 571544, characterized in that, in order to expand the field of research and increase the reliability of its work, it is provided with an elastic cylindrical cover with plates placed with a gap inside the working chamber and attached at its ends, and the plates are attached to the inner surface of the cylindrical shell along it forms with a gap between them, and the gap cavity between the cylindrical shell and the working chamber is hydraulically connected to the hydropulsator. Sources of information taken into account in the examination 1. USSR author's certificate 5 No. 571544, cl. E 02 D 1/00, 1975 (prototype). C