RU36479U1 - WELL SYSTEM FOR THE DEVELOPMENT OF A Trench Of A PIPELINE IN FROZEN SOILS AND ITS WELL - Google Patents

Description

WELL SYSTEM FOR THE DEVELOPMENT OF A Trench Of A MAIN PIPELINE IN FROZEN SOILS AND ITS

The useful model relates to construction and can be used to extract trenches of trunk pipelines in frozen soils. It is known that at low temperatures most soils dramatically change their properties. This is due to the fact that many soils contain in different quantities water in a free or capillary state. Water turning into ice binds mineral particles of soil into a solid, and the more water freezes at low temperatures, the stronger the soil becomes. In this regard, the difficulty of developing frozen soils compared with thawed soils increases significantly. Freezing of the soil is observed in those areas where there is a stable negative air temperature in relatively long periods of the cold season. The freezing depth and hardness of frozen soil depend on the duration and magnitude of winter frosts, the nature of the soil, the level of groundwater, the presence of a vegetation layer, the thickness of the snow cover, the strength and duration of the wind and other conditions. To facilitate the development of frozen soils during the construction of trunk pipelines in winter, measures are taken to protect the soils from deep freezing. So the soil from dumps intended for backfilling trenches is loosened by mechanized methods and thaws are thawed. Loosening of frozen soil during the development of the trench by crushing is usually carried out at its thickness; it does not exceed 25 cm.With the thickness of the frozen layer up to 0.6-0.7 m, crushing of the soil is carried out by impact devices suspended from the boom cable of an excavator or crane. Soil cleaves as a result of several blows on one track.

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A well-known method of cutting a frozen layer of soil from the prior art

blocks with the help of bar machines are effective in urban conditions when digging pits and are not applicable for trench excavations, when soil fragments are used for backfilling trenches, since the current SNiP limits the largest permissible size of frozen clods and their content in the ground of filling the main pipeline.

A device for the deep method of heating the soil with a large thickness of the frozen soil layer is known. The soil is heated using heating devices in the form of needles installed in drilled in the frozen layer of the well. Needles can be steam, water circulating and electric. Water and steam needles require special boilers to produce hot water, steam generators.

With a freezing depth of 1.3-1.5 m and large developed volumes of soil in the field, an explosive method is used - the most economical and effective (see A. Shalnov, Construction of gas networks and structures Moscow, Stroyizdat, 1980, p. 142- 145).

Known methods of explosive loosening of frozen soil. One of them consists in drilling a well in a frozen mass of soil, laying a charge of explosive (BB) in it, creating a soil clogging over the explosive charge and blasting a charge (see AFONIN V.G. et al. Blasting operations in construction. Quick reference, Kiev, Budivelnik, 1971, p. 140).

When drilling a well for loosening frozen soil to the entire depth of the trench, ground water accumulates at the bottom of the well, as a result of which the explosive charge does not provide a high explosive effect, since water acts as a buffer. The process of creating a well in frozen ground is time consuming and energy intensive. The creation of soil clogging in a well requires the presence of mineral soil of a certain fraction, usually imported mineral soil.

2 sinking a well in frozen ground by thawing it with

a jet fuel device until the bonds between the soil particles are mixed and mixed, the explosive charge (BB) is placed in the well until the heavy soil fraction precipitates in the bottom of the well and the explosive charge detonates after the heavy fraction freezes in the bottom of the well (see SU 1745923 A1 07/07/1992). This device - the well does not provide a good study of the bottom of the trenches and its slopes.

It follows from the foregoing that there is the task of effectively forming wells in frozen ground that provide a given section of the trench in frozen ground, as well as excluding a certain fraction from the technological process of imported mineral soil through the use of soil in the well section.

The claimed utility model is aimed at solving this problem. In the implementation of the claimed device, the technical result achieved is the effective formation of wells in frozen soil, which ensure predetermined crushing of frozen soil when a trench of the main pipeline is torn off and the necessary study of the bottom of the trench and its slopes.

This problem is solved by the fact that the well system for developing the trench of the main pipeline in frozen soils contains wells drilled from the soil surface by thawing the frozen soil with jet fuel elements to break the bonds between the soil particles and mix them, explosive charges (explosives) placed in the wells and well plugging in the form of a frozen soil fraction that has precipitated from the pulp, in which, to improve the quality of soil crushing and improve the development of the bottom of the trench in each well not depending on its depth formed at least one local broadening bottom of which is located at the calculated distance from the trench bottom design level in each well calculated charge weight

3 BB is located under or in local broadening, while

made in the form of a frozen pulp in the cross section of the wells, and the latter are arranged in two rows, at least according to the stepwise scheme when developing trenches up to m wide, and not less than three rows, with a larger trench width. In addition, when developing trenches in strongly icy soils and the number of local broadening in the well 2 or more, the total charge length does not exceed 2/3 of the well depth, and its jamming over each top explosive charge was carried out using local or imported mineral soil. To solve this problem, a well for the development of a main pipeline trench in frozen soils contains a charge of explosive (explosive) in its cavity, its clogging in the form of a frozen fraction of the soil that has fallen from the frozen pulp soil obtained during thawing, while improving at least one local broadening, the lower of which is located at the estimated distance from the design level of the bottom of the trench, and an even mass of explosive charge is located under each local well broadening or in it; the stemming is made in the form of a frozen pulp in the well section. In addition, when a well is thawed in very icy soils and the number of local broadening in the well is 2 or more, the total charge length does not exceed 2/3 of the well depth, and its clogging over each top explosive charge is carried out using local or imported mineral soil.

The utility model is illustrated by graphic material, where in FIG. 1 (a, b) shows in plan a diagram of the installation of metal needles for drilling holes in frozen ground; figure 2 is a section of a well with an explosive charge installed in it; in FIG. 3-5 - various cross-sectional shapes of wells, taking into account local conditions of soil freezing in the area of pipeline construction.

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4 In accordance with the claimed utility model for destruction

frozen soil within the contour of the trench (1) in the soil massif (2) is drained; wells are created (3) by thawing the soil with metal steam needles (4). Depending on the degree of saturation of frozen soils, various modes of using steam needles immersed in thawed soil are possible. Immersed needles can work in sections mounted, for example, on an L-shaped boom mounted on a mobile drilling machine or on a bulldozer with the replacement of its blade with the indicated boom. For vertical needle mixing, it is possible to use a drilling machine drive, an individual drive, or a manual mechanical drive. Well drilling in frozen soils is drained through steam needles. With help; and such a needle receive a high-temperature high-pressure jet with a jet diameter of 25-30 mm. By adjusting the jet regimes in terms of temperature, pressure and duration of action (temperature 150-200 degrees C, pressure 10-15 atm., Duration 10-15 minutes) simultaneously with the destruction of frozen soil by thawing it, local broadening (5) of the well is created, for example , when the steam needle stops at a given depth, the soil is saturated with water and the soil is turned into pulp. Local broadening is made in the form of chambers, under which or in which, depending on the properties of frozen soils, explosive charges are placed (6), while local broadening allows soil fractions and, most importantly, heavy fractions to be separated from the host rocks (7). Simultaneously with the thawing of the soil, there is a violation of the bonds between the soil particles due to the pulp bubbling, chaotic weighing of soil particles in the pulp within the well is carried out. After removing the needle from the well, a heavy fraction (7) of the soil precipitates from the pulp. Before the end of this process, the explosive charge (6) is placed in the bottom hole (8), around which until the soil freezes,

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5

guaranteed formation of a clogging layer from large heavy fractions (7) of the soil. The experiments (see GOST 12536-79 Soils ...) confirmed layer-by-layer separation of solid particles deposited from the pulp into fractions: first a layer of large particles (heavy fraction) is formed, then a layer of small soil particles is formed from medium and higher. Explosive charges explode after freezing fractions in the cross section of the wells, especially the heavy fraction (7), while the blast wave to the frozen ground mass passes through a densely formed frozen hard layer of the heavy soil fraction. In the case of thawing of very icy or finely dispersed soil and the presence of two or more local broadening in the well (depending on the depth of the well) after immersion of the upper explosive charges, the well should be filled to 1 / 3-1 / 2 of its depth (according to calculations) with soil. Frozen pulp and water in the well also serve as stemming (9) for explosive charges placed in the well. Depending on local conditions and the time of year when drilling wells to a considerable depth, casing of the wellhead within the seasonal thawed soil layer is possible.

To improve the quality of crushing and a good study of the bottom of the trench, it is recommended to place more powerful explosive charges in the bottom of the well, with half of the estimated charge mass being located in the lower third of the well, and the total charge length should not exceed 2/3 of the well

These recommendations are in good agreement with the shape of the wells shown in Figures 4, 5. The cylindrical part (10) of the well is located below the level of the bottom of the trench (bore hole), the lower broadening (5) is at the estimated distance from the design level of the bottom of the trench, preferably at the design level bottom of the trench. Thus, the placement of the main part of the explosive charge is in good agreement with these recommendations. In addition, broadenings filled with frozen fine fractions of soil and water (5) contribute to a better use of energy 6

blast wave to destroy and crush the rocks of the frozen mass of soil, since it is known that the energy of the explosion propagates along the line of least resistance (LNS). When digging trenches in frozen soils, it is possible to use vertical and inclined borehole charges of various diameters, while steam needles are installed at a calculated distance from each other, depending on the required degree of crushing of frozen ground and obtaining the contour of the trench.

Since the mobility of the blasted rock layer varies from 3 to 7 m, the maximum diameter of the wells (without local broadening) reaches 100-200 mm. The diameter of the local broadening of the well is from two to three diameters of the well. To improve the quality of crushing when blasting layers of mosh; up to 6 m in thickness, combined schemes of breaking with well charges of various diameters should be used: from large 200-165 mm to small 100 mm or less. The number of rows of charges and the distance between them are taken depending on the given width of the trench, the properties of the exploded frozen rocks, and the power of the used construction machines. So when driving a trench up to 1.5 m wide, explosive charges in the wells are preferably arranged in two rows in a stepwise pattern (see figa). The distance between wells with a diameter of up to 100 mm along the axis of the trench is 0.8-1.6 m. Charges should be removed from the axis of the trench at a distance of 0.6-1.0 m. The size of the rebound varies within 0.3-0.5 m. When digging trenches of greater width, the charges are arranged in no less than three rows (see figLb). For a well with a diameter of 120 mm, the average distance between charges is 1.5-2 m, and the magnitude of the overhead is assumed to be 0.1 mosh; the explosive layer. In this case, the specific consumption of explosives can be taken as during the breaking of volcanic rocks and granites (0.6-0.75 kg / m). When loading waterlogged wells, a well-known water-containing explosive is used. It is possible to use a cutting scheme for short-blown blasting, in which the deceleration interval between adjacent rows is 50 and 100 ms. In terms of improvement

the quality of crushing of the frozen ground mass the most optimal is the use of a wedge blasting scheme, and to limit the width of the collapse of the rocks when the charges are arranged in more than three rows, a wedge scheme with a side cut can be recommended. As a means to initiate explosive charges, use, for example, a detonating cord, while the main network is detonating; its cord is located above the charges or to the side of them. At the same time in the group explode from 2 to 4 charges. In order to reduce the search over the width of the trench, it is desirable to use wells with a diameter of not more than 100 mm and position them no closer than 0.3-0.5 m from the design contour of the trench. To reduce the disturbance of the walls of the trench, the mass of borehole charges should be reduced by placing them on an approximate grid, while using well-known explosive materials for flooded rocks, eliminating failures when blasting along narrowed grids. When the ice content of the soil is more than 0.4 and the number of local broadening in the well is 2 or more, it may be necessary to fill the wells above the upper explosive charges, after being placed in the well, with local or imported mineral soil. Thus, the claimed group of inventions simplifies the process of drilling wells in frozen, equivalent to rocky soils, improves the quality of crushing of the soil used for backfilling the trench after laying the pipeline in it, and also increases the degree of useful use of explosive charge energy. 8

Claims (4)

1. A well system for developing a main pipeline trench in frozen soils, containing wells drilled from the soil surface by thawing frozen soil with jet fuel elements to break the bonds between the soil particles and mixing them, explosive charges (HE) placed in the wells and bore holes in the form a frozen fraction of soil that has precipitated from the pulp, characterized in that to improve the quality of crushing of the soil and to improve the development of the bottom of the trench in each well, depending on at least one local broadening is performed, the lower of which is located at an estimated distance from the design level of the bottom of the trench, in each well, the estimated mass of explosive charge is located under or in local broadening, while the clogging is made in the form of a frozen pulp in the section of the wells, and the latter are arranged in two rows, no less than in a stepwise pattern when developing trenches up to 1.5 m wide, and no less than three rows with a larger trench width. 2. The well system according to claim 1, characterized in that when developing trenches in very icy soils and the number of local broadening in the well 2 or more, the total charge length does not exceed 2/3 of the well depth, and its jamming over each top explosive charge is carried out using local or imported mineral soil. 3. A well for the development of a trench of a main pipeline in frozen soils, containing a charge of explosive (BB) placed in its cavity, its blockage in the form of a frozen fraction of soil that has fallen from the pulp obtained during thawing of frozen ground, characterized in that to improve the quality of soil crushing and working out the bottom of the trench in the well, depending on its depth, at least one local broadening has been performed, the lower of which is located at the estimated distance from the design level of the bottom of the trench, the estimated mass for BB venom located beneath each well or a local broadening therein and tamping is in the form of frozen pulp sectional wells. 4. The well according to claim 3, characterized in that when the well is thawed in very icy soils and the number of local broadening in the well is 2 or more, the total charge length does not exceed 2/3 of the well depth, and its jamming over each top explosive charge is carried out using local or imported mineral soil.