SU1745840A1 - Device for loosening frozen earth prior to excavation - Google Patents

Abstract

Use: construction machinery. SUMMARY OF THE INVENTION: The device has an air-heating and sealing device communicating with the air duct through the gate valves, a protective grid for fencing the collecting body, nozzles placed on the body, angled to the longitudinal axis directed upwards. The sealing and air heaters can be made in the form of an inflatable wheel chamber and an electric muffle heater. 1 hp ff, 1 ill.

Description

The invention relates to construction equipment used in the construction of various departments for loosening and weakening the structure of frozen soils in harsh climatic conditions before they are excavated by earth moving machines in surface conditions and underwater hydromechanization equipment when developing various trenches, dredging slots, grooves, geological cuts, quarries of minerals, nonmetallic materials, etc.

A device rotating in a borehole with its broadening is known, consisting of two coaxial (one inside the other) cylinders with side and end hydraulic and pneumatic nozzles surrounding them, two pipelines supplying them with a stream of purified high-pressure water (under a pressure of 30-70 MPa ) and compressed air (under pressure 0.5-0.7 MPa). In the process of broadening the well to the desired diameter, the rotating device is lifted. In this case, the frozen ground around

the wells are loosened by water jets, mixed with water and expelled to the outside in the form of pulp released into the atmosphere with compressed air.

The drawbacks of this device are considerable power consumption and complexity of the design, which requires for the operation of the mechanisms of rotation, lifting, and supplying compressed air to the rotating nozzles of purified, highly permeable water. This reduces its reliability, complicates operation, and increases the cost of developing frozen ground.

Closest to the proposed device for expanding the well, including a rotation mechanism, gives coaxial pipes closed below, one inside the other, of which the outer one is the body carrying the discharge pipe from above and internally connected to the source of the working fluid and at several intervals with a nozzle head in the form of a hollow ring placed in the body cavity, the nozzles being oriented perpendicular to the lateral surface of the well, and

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.N SL

with

Q Q

the walls of the housing are made holes located on both sides of the nozzles. The device loosens the soil around the well, mixes it with the working medium, which, by the action of the residual head, forces the resulting mixture out of the well through the holes in the housing cavity with the discharge port.

The disadvantages of this device are complexity, low reliability of the design, high energy consumption associated with the necessity of its rotation, using a high-pressure working medium for feeding nozzle heads. This leads to low efficiency and high cost of loosening and removing frozen soil during well expansion.

The purpose of the invention is to increase the efficiency of loosening frozen soil by exposing heated well jets to the walls of the well, causing the formation of cavities, cracks and water-soil mixture removed by the ground pump in soils.

This goal is achieved by the fact that a device for expanding wells, including a cylindrical, end-closed housing, on the outer surface of which, at regular intervals along the height of the parameter, nozzles are located perpendicular to the longitudinal axis, an inner pipe placed coaxially with the housing inside it, an air duct, communicated with cavities of the body and nozzles, and a curved pipe for pulp removal, additionally equipped with an air heating and sealing device, a protective grille and a ground pump the cavity of which is communicated through the valve with the air duct and the inner tube, and the soil collecting organ is placed on the end of the inner tube located below the end of the body and enclosed by a protective grid placed concentrically protruding end of the inner tube. In this case, the nozzles of the upper rows are directed at an angle to the longitudinal axis, directed upwards, and the air-heating and sealing devices are placed at the upper end of the housing, communicated, like the sealing device, through the valve with the air duct.

The drawing shows a side view in section of the device for loosening frozen soil.

The device is made in the form of two coaxially placed pipes-pipes of the outer 1 and inner 2. The nozzle 1 is connected through valve 3 to the air line A of the compressor. At its upper end, two devices are mounted: a sealing 5 and an air-heating 6, for example, a rubber wheel chamber and an electric ring muffle heater. Before

a heater 7 connects a pipe 7 with a valve 8 and a pipe 9 with a valve 10, which connect the sealing device 5 and the working nozzle 11 of the pneumo-ejector 12 with the air pipe 4.

0 The lower end of the nozzle 1 is plugged and the end part of the nozzle 2 with an open end of 0.1-0.2 m in length, fenced with a protective grid 13, is passed through it. Outside on the nozzle 1, starting from the bottom, through the specified

5, the height gaps at the length of the perimeter are mounted at an angle to the longitudinal axis, directed upwards, interchangeable nozzles 14 with the same or different area and shape of the output from the versts, allowing

0 Change the air flow between the individual nozzles and their area of operation.

The upper end of the nozzle 2 is connected to the receiving nozzle of the receiving chamber of the injector 12. The pressure hose 15 unites the air injector 12 with a place for storing the soil.

The device works as follows.

At the site of the forthcoming excavation, depending on the width of the site of drilling a well, with an elevation above the design level of the bottom of the created structure by 0.2–0.3 m in one or several symmetric rows. Distance between rows and

5 wells in rows set the same. To loosen the structure of the frozen soil at the site of excavation, around each well a void hole with a length of at least half the distance between the rows and boreholes and cracks formed by the action of several hot radial jets emanating from the nozzles 14 of the nozzle 1 are created on the walls of the well and removing from its bottom through the end of the pipe 2

5 with a pneumatic ejector 12 into the dump of flowing melt water from the melted ice with a part of the scavenged fractions of the soil and cooled air. To do this, the device is alternately lowered into each well before touching

0 protective grid 13 of its bottom. The air pipe 4 connects the open end of the pipe 1 with the compressor, and the air-heating device b is connected by cable to the power source. Then

5, the air-heating device 6 and the compressor are activated, with compressed air from the air pipe 4 through open valves 3,8 and 10, after heating the air-heating device b into pipe 1, and the pipes 7 and 9,

feeding with cold compressed air sealing device 5, which overlaps the wellhead, and pneumatic ejector 12.

Heated air-heating device 6 compressed air is released from the pipe 1 through the nozzle 14 on the walls of the well. Under the action of heated air jets in the frozen ground around the well, inclined hollow-voids form in the form of diffusers elongated in the direction of their action, and cracks from tensile forces arising from the temperature difference at the boundaries of the jets.

Thus, the loosening and weakening of the structure of the frozen soil, sufficient for subsequent excavation, occurs. Formed from diluted ice water with part of the fine and coarse fractions washed off by it and cooled air flows to the bottom of the well, where fractions that exceed the inlet port of the nozzle 2 are retained by the protective grid 13 and the pneumatic ground mixture is sucked through pipe 2 by ejector 12 and guided along sleeve 15 to the place of ground folding

The loosening of the frozen soil structure around each well is continued until radial hollow cavities of at least half the distance between the wells and their rows and cracks are formed in it.

Under the surface conditions for complete dewatering of the hollow holes, the pumping of the pulp wells continues for some time after the cessation of the supply of hot compressed air. In cases where excavation takes place over a considerable period of time, the wells from the top are isolated, for example, by backfilling snow.

Claims (2)

1. Device for loosening frozen soil before excavation, including a cylindrical body closed from the end, on the outer surface of which, at regular intervals along the height perpendicular to the longitudinal axis, there are nozzles, an inner tube positioned coaxially with the housing inside it, an air duct connected to the cavities of the body and nozzles, and a curved sleeve removal of pulp, characterized in that, in order to increase the efficiency of loosening frozen soil, it is equipped with air heating and sealing devices, protective grille and the ground pump, the cavity of which is communicated through the valve with the air duct and the inner tube, and the soil collecting organ is placed on the end of the inner tube located below the body end and enclosed by a protective grille located concentrically protruding end of the inner tube, while the upper rows of nozzles are angled to the longitudinal the axes are directed upwards, and the air-heating and sealing devices are placed at the upper end of the casing pipe and communicated through the valve with the air duct. 2. A device according to claim 1, excluding that the sealing and air-heating devices are made in the form of an inflatable wheel chamber and an electric ring muffle heater.