RU1810705C - Method for laying underground pipelines in frozen grounds - Google Patents

Abstract

SUMMARY OF THE INVENTION: a trench is torn off and slits are cut along its sides. They lay the pipeline in a trench and fill it and the cracks with soil. Slots are cut within the length of the area of polygonal ice and the intersections with them are filled with a foam-forming composition. Slots are cut to a depth of 1.2-1.6 depths of the pipeline and a width equal to 0.1-0.2 of its diameter. In the zone of intersection of the pipeline with ice, screens are created at its base. The slots are cut obliquely until they intersect with the pipeline. Screens are created from panels of synthetic material. 3 C.p. f-ly, 3 ill.

Description

The invention relates to construction and may find application in the laying of pipelines.

The purpose of the invention is to increase the operational reliability of the pipeline when laying it along sections containing polypanal vein ice areas by protection against frost cracking.

In Fig., 1 shows a schematic plan of a section containing polygon-ice ices with a main pipeline laid through it, in Fig.2 - section AA in Fig.1, the first option; in Fig. 3 is the same, the second option.

The method of laying an underground pipeline in permafrost soils in areas of polygonal vein ice with lines 1 of their concentration consists in extracting a trench 2 and cutting slots 3 along its sides, laying in a trench from pipeline 4 and filling the trench and slots with soil 3.

Slots are cut within the length of the area of polygonal vein ice and in the zone of intersection with them, the slots 3 are filled with a foaming composition 6. The slots are cut to a depth of 1.2-1.6 depths of the pipeline and a width of 0.1-0.2 of them diameter. In the zone of intersection of the pipeline with polygonal vein ice, screens 7 are created at its base.

There may not be a trench 2 if the placement of the pipeline at the level mark is carried out by force indentation after thawing of permafrost by heating.

The slots are cut both vertically and inclinedly, and their removal from the pipeline body is assigned as the optimal least condition for the maximum damping of the possibility of frost cracking of the soil in the areas between each slot and the pipeline. In the case when the intersecting lines 1 polygon 00

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of vein ice have very narrow sections (as can be seen from their figure on the walls of the open trench), inclined slots pierce additionally until they cross each other in the line zones and thereby combine the formation of side screens with screens 7 at the base of the pipeline. In the case of a sufficiently large width of the cross sections of lines 1 of polygonal vein ice, the screens 7 at the base of the pipeline are formed by laying out panels of synthetic material on the surface of the bottom of the trench 2 before laying the pipeline on it (or press down under it if immersed).

The introduction of composition 6 into the slots is carried out at the final stage of work. At the same time, the soil extracted from the cracks is poured into the gap space between the sections of polygonal vein ice.

When frost cracking occurs along lines 1 of polygonal vein ice of cracks running from the initial source of the thermokarst process towards the pipeline, it reaches only a gap on the surface and a shallow depth and does not spread further, since the gap space serves as a limiter to the running of cracks, which as for the soil located below the gap, the crack in it runs under the pipeline and even rises to it, however, it does not reach the pipeline, since the lower screen 7 prevents this in particular the cloth. The soil sections on the sides of this panel (within the distance between the slits) are narrow and. if they are captured from below by a running crack, they are not capable of seriously affecting the pipeline due to the labyrinth of access to it from below.

The used foaming composition does not have elastic properties and therefore the crack does not transfer from one wall of the gap to another. Under the conditions that

the work of the foaming composition in the gap is similar to the work of air, the presence of the composition is necessary only to prevent water from entering the gap, i.e. environment

conducive to crack running after freezing.

At the same time, the soil backfill of cracks in the areas between the sections of polygonal ice provides normal

water exchange between soils located on different sides of each of the cracks 3.

Thus, due to the presence of cracks with a foaming composition in the areas of polygonal vein ice, the laid pipeline is protected from frost-cracking, as a result of which the operational reliability of the pipeline is increased.

Claims (4)

1. A method of laying an underground pipeline in permafrost soils in the area of polygonal vein ice, which consists in extracting a trench and a cut ke along its sides of the cracks, laying in a trench pipeline and backfilling of the trench and slots with soil, characterized in that the slots are cut within the length of the polygon-vein ice section and in the zone of intersection with them, the slots are filled with a foam-forming composition, while the slots are cut to a depth of 1.2-1.6 pipeline laying depths and width), 1-0.2 of its diameter, and screens are created at the base of the intersection of the pipeline with polygonal ice ice at its base. 2. The method according to claim 1, characterized in that the slots cut obliquely. 3. The method according to PP. 1 and 2, with the exception that the slots are cut obliquely until they intersect under the pipeline. 4. The method according to claims 1 and 2, characterized in that the screens are made from a panel of synthetic material.