Varieties of benchmarks, their design. Reference point - what is it? What are reference points for in construction, geodesy, business or science? Benchmark geodetic

We are accustomed to the fact that a modern city is permeated by a variety of networks - communications, water supply, gas, transport, and so on. There is another network among them, not entirely invisible, but little known to the uninitiated. You may have noticed metal signs hammered or cemented into the walls of buildings. They're called geodetic benchmarks and together they make up the state leveling network (GNS).

One of the best descriptions geodesic benchmarks can be found in the technical encyclopedia of 1934.

Once, a couple of years ago, I tried to clarify some questions for myself, but it turned out that there are a dime a dozen materials on geodesy on the Internet, but it’s not so easy for an ordinary person to understand this mass of information, and especially in relation to our Chelyabinsk realities. And recently I had the opportunity to ask questions to experts. They were answered:

Sergei Reingoldovich Reizvich- Director of LLC NPF "Nedra".
Sergei Vasilievich Vorobyov- a former leading employee of the architecture of Chelyabinsk, responsible for the creation, maintenance and development of geodetic networks.
Vladimir Nikolaevich Ivanov- cadastral engineer.
Dmitry Yurievich Mylnikov- Head of the department of design automation PC GPI Chelyabinskgrazhdanproekt.
Evgeniy Anatolievich Maslov- Head of Department for the Protection of State Secrets and mobilization training branch of the Federal State Budgetary Institution "FKP Rosreestra" in the Chelyabinsk region.

What are rappers and what are they for?

D. Mylnikov: rappers And wall leveling marks are part of the leveling (altitude) network, which serves to measure the height relative to sea level when performing various engineering and construction works. On the territory of Russia, the sea height is measured relative to the zero of the Kronstadt footstock and is called the "Baltic system of heights". All benchmarks are made in such a way that they can be installed or hung from a special hole leveling rail, with which height measurements are made.

S.R. Reyzvich: At present, after leveling the state height network from Kaliningrad to Anadyr, the height marks are determined in the Baltic system of heights of 1977, which differs from the Baltic system by an average of 20 cm in the Chelyabinsk region.

D. Mylnikov: To determine the exact position on the ground, that is, coordinates, points of the state geodetic network (GGS) are used. The difference between GGS points and high-altitude benchmarks is that they have a clearly defined center, the coordinates of which are determined. Each item must be marked with its number, which is entered in the catalog. All other parameters of the item are determined by the catalog. In addition, the year of foundation, the name of the organization and other parameters that are not mandatory can be applied. At the same time, in practice, even the absence of a number on the benchmark is not critical, since all items are also marked on topographic maps and plans, as well as in the so-called "outlines" (schematic plans), according to which surveyors find them on the ground.

GGS points are the so-called "geodesic towers", which you probably saw outside the city. At the same time, the tower itself is needed only so that it can be seen from afar, and the point itself is located under it in the form of a special sign filled in concrete base. At the same time, the most accurate points of the 1st class and the astronomical-geodesic network have one more duplicate sign at depth, which will be used to restore the point in case of damage. The coordinates of these points are calculated with very high accuracy, for points of the astronomical-geodesic network - using special astronomical measurements relative to the position of the stars. GHS points are usually also points of the leveling (altitude) network, since for them, in addition to coordinates, the height above sea level is also determined.

S.R. Reyzvich: In turn, in urban conditions, the benchmarks of the leveling network are also very often used as GGS points - for such points, not only the height is determined, but also the coordinates in one or another geodetic coordinate system associated with the Earth's surface.

D. Mylnikov: In addition, there are so-called points local geodetic networks, which are also called support and boundary networks(OMS). They are created in settlements and are used in determining the boundaries of land plots and marking work during construction, that is, in determining the place exactly where you need to build a house or lay a road. Such points do not have geodetic towers. During the construction of large facilities or the development of large sites, temporary benchmarks and points are often created for the period of work, which makes it possible to speed up and simplify the entire process. Often these are temporary structures, for example, a metal pipe or rail hammered into the ground, the top of which serves as a mark, therefore, after construction is completed, they cease to exist.

E. Maslov: Support and boundary networks are also installed by surveyors, but they are used for local purposes, for settlements somewhere in the region - in Sosnovka, Argayash, etc. After the completion of the work, the surveyors, according to the act, transfer the compulsory medical insurance to the municipality, and then the municipality is responsible for their safety. Such tags are taken into account for individual directories.

S.R. Reyzvich: What else are rappers used for? To identify the impact of man-made processes during the construction of structures on quicksand, roads, bridges, subway lines, special observation stations are installed - in urban conditions they are also laid in the form of wall benchmarks.

The existing wall benchmarks are of great importance, since they were used to link and lay out the construction elements of the adjacent territory. If there are discrepancies in the position of the boundaries of buildings, structures, land plots, these wall benchmarks are the basis for conducting a forensic geodetic examination.

What are rappers?

S.R. Reyzvich: There are several varieties. Age-old rappers provide long-term preservation of the elevation mark, they are not found on the territory of the Chelyabinsk region. Fundamental benchmarks located along railway and are reinforced concrete pylons 30x30 cm, in which metal signs are laid. In the rest of the region, the high-altitude network is represented by ground And wall benchmarks.

D. Mylnikov: Ground benchmarks necessarily have a concrete base - an "anchor", into which a metal, usually cast iron, mark with marking is poured. Wall benchmarks installed in the foundations of the rear and structures, including in the supports of bridges.

V. Ivanov: You can read more about the types of benchmarks.

S.R. Reyzvich: Rules for the design of benchmarks -.

What other information can be obtained by looking at a particular benchmark?

D. Mylnikov: Usually, its number and the name of the manufacturer are cast on the benchmark, sometimes the year. An engraved height value is sometimes found on ground benchmarks. All other parameters, except for the number, are optional and not always accurate, since all the exact parameters of the leveling network points are recorded in a special catalog.

The number on the benchmark is often not the serial number of the item, but the unique number of the piece of iron itself, which is assigned to it during manufacture at the factory (like the body number of a car). Likewise, the year that is cast and not engraved is the year of manufacture of the sign, and not the year of its installation. That is, everything that was cast was applied at the factory at the time of manufacture, and cannot be associated with a specific place and time of installation of the sign. Everything that is engraved (cut out) is applied already at the moment or after the installation of the sign and refers to the parameters of a particular sign in a particular place.

But even the presence of a number on the benchmark is not mandatory. In the catalog of points of the geodetic and leveling networks, in addition to the number and parameters, there is always an "outline", that is, a diagram of the location of the benchmark or point on the ground. In addition, points are often applied on the duty topographic plan. locality. At the same time, in practice, usually, first, according to the topographic plan or outline, they find out where the benchmark is approximately located next to the work site, and then they are already looking for it on the ground. The probability that several benchmarks or points will be laid nearby is very low, so the absence of a number for it practical use not critical.

E. Maslov: The directory of references also indicates the address of the object. By the time of laying it, it is already known, since the benchmark is set after the building is built. That is, construction begins with surveyors, and ends with them.

Who is responsible for creating, recording and storing information about benchmarks?

D. Mylnikov: The catalog of points of state networks is stored in the state geodetic fund, for which this moment the state service of registration, cadastre and cartography is responsible.

E. Maslov: The catalog is labeled "For Official Use". Currently, all organizations performing cartographic and geodetic work are required to receive this data and use it in their work.

In what years did they begin to install benchmarks and when and why did they stop doing this?

D. Mylnikov: Benchmarks began to be actively installed in the 30s, when industrialization and the construction of large industrial enterprises and residential buildings. Although leveling and geodetic networks were created even before the revolution, for example, during the construction of the Trans-Siberian railway, which passed through Chelyabinsk. At the same time, in different time the marking and the amount of information on the benchmarks were different. In order to find out now what and where was indicated, you need to raise the archives, look at the reports on the progress of work on their installation.

New benchmarks and signs are still being installed, but mainly where new construction is underway. It makes no sense to install new benchmarks in the old quarters, since there are enough old ones, and the number of works for which they are needed is less in the old built-up area. In principle, the main purpose of the benchmarks and points of geodetic networks is precisely to fix the reference position for as much as possible long time. In practice, this means that as soon as one or another territory is basically built up, the installation of new benchmarks on it also stops. And until some large-scale reconstruction begins, when the old buildings are demolished, in the foundations of which the benchmarks are laid, no one will install new ones.

True, in recent years, due to the development of technologies for performing work using GPS and GLONASS, the need to install benchmarks and points of the geodetic network has sharply decreased. This does not mean that they are not needed at all, but now they can be installed much less often (with large distances from each other).

S.R. Reyzvich: As far as I know, the last benchmarks were installed during the construction of the subway. These are ordinary metal signs laid along Lenin Avenue to the Aeroflot agency. As a recent example, we can also cite our benchmarks on the building of the legislative assembly of the region, which were laid around 2002.

What measures are taken (were taken) to preserve the benchmarks, are they periodically inspected, restored?

D. Mylnikov: The state geodetic and leveling networks are protected by the state; administrative punishment. As for benchmarks, most of them belong to local networks, for which the municipality is responsible, which should monitor their safety. But due to the fact that recently there have been constant changes in the state authorities responsible for geodesy and cartography, which from a separate service have now become part of public service registration, cadastre and cartography, no one really does this really. That is, the problem of the safety of benchmarks and geodetic points exists.

As such, there is no special examination of the points at present. Usually it is replaced by constant use in the process of performing geodetic work. In the event that a specialist finds any problems with an item, he usually reports this to the accounting authority (if only because he has to take the parameters of another, neighboring item).

Local networks usually do not restore damaged or lost points, since it is easier and faster to lay a new point and determine its parameters. If there is a suspicion that the position of the benchmark or point is violated, then you still have to make new measurements at neighboring points. And if the sign itself is lost, then the new sign may have other sizes and a different registration number.

V.S. Vorobyov: At times Soviet power inspection of points was carried out, special money was even allocated for this. In 1992-1994, as far as I know, on the territory of Chelyabinsk, the cycles of observations of the settlement of buildings and structures in the metro construction zones were annually carried out by a small, but quite qualified enterprise, MUP Chelyabgeocenter. After the termination of its existence, the banner was picked up by Uralmine Surveying, which makes observations to this day, for which it is honor and praise - it is very difficult in our mercantile time to obtain funding for such work, which does not promise momentary benefits.

As for the responsibility for safety, I personally do not know of a single case where someone was really punished for the destruction of the state geosign. The main trouble is facing works on facades.

E. Maslov: In the city, the destruction of points is not so noticeable, because it is mainly iron and concrete, and even wooden towers still remain in the area. Some of them are tumbled down and destroyed. They are not monitored - this is also due to mismanagement, but also because there is no great need for them - GPS is increasingly being used.

Why is the concentration of benchmarks in the city center higher than on the outskirts?

D. Mylnikov: Where work was carried out more actively, there were more benchmarks and points installed. At the same time, the center is usually built up more densely, the line-of-sight distance between the points required for measurements is less, therefore, in order to simplify and speed up the work, they tried to install more benchmarks and points. In new areas, the building density is lower, the line-of-sight range is greater, so the benchmarks can be installed at a greater distance from each other. In addition, with the advent of new equipment, such as laser levels or geodetic GPS / GLONASS receivers, the installation density can be significantly lower.

E. Maslov: By the way, this picture is typical not only for Chelyabinsk. For example, in Moscow, 20 out of 22 points are located in the city center.

Are the anchor bookmark and the building connected in some way? Is there any way to determine the date of construction from the benchmark?

S.R. Reyzvich: No. Indirectly, the benchmark can talk about nearby construction or the presence dangerous objects(metro, thermal power plant, etc.).

D. Mylnikov: There is no clear connection between the benchmark and the building. Firstly, the benchmark can be installed in the building much later than its construction. Secondly, since the year of manufacture of the sign itself is indicated on the sign, it could have been cast before the building was built.

As for the shape of the rapper, then a separate study needs to be carried out. For a surveyor, it is not so much the form that is important, but the safety of the sign and the convenience of its use. On the other hand, in the days of the USSR, signs of benchmarks were produced centrally, so the shape of the benchmark will rather speak about the history of the production of signs. When, at what plant, etc. At the same time, the benchmarks were installed at different times, that is, both old and new ones can stand on the same territory. A new benchmark could be installed to replace the lost one, etc.

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Reference points in geodesy

Benchmark (from French repere - sign, starting point) - a sign that fixes a point on the earth's surface, the height of which relative to the original level surface is determined by leveling.

IN Russian Federation the heights of the benchmarks are calculated relative to the zero of the Kronstadt footstock.

The benchmarks of the state leveling network serve as starting (reference) points for determining the heights of intermediate points of the earth's surface when topographic surveys And different kindsurvey work , and are also used for scientific purposes when studying the difference in sea levels.

Benches according to their importance are divided into:

1) age-old

2) fundamental

3) privates.

Centuries-old benchmarks are distributed throughout the country, according to a special scheme, in places established by the instruction, mainly for scientific purposes. The depth of the bookmark is determined by the occurrence rocks.

The fundamental benchmarks, which are reinforced concrete pylons, are laid in the ground every 50–80 km on all leveling lines of the 1st class, as well as on the most important lines of the 2nd class and near the most important offshore water meters.

Ordinary benchmarks, laid after 5--7 km on leveling lines of all classes, are divided into ground, installed in the ground, rock (fixed in rocks) and wall, laid in the walls of capital structures.

In hard-to-reach areas, the distance between benchmarks can be increased to 6-7 km, and in seismically active areas it should be reduced to 3-3.5 km.

Wall anchors are fixed in the built-up area wherever possible. Fastening is carried out in the bearing parts of stone or concrete structures at a height of less than 0.3 m using leveling marks.

Rock benchmarks: ordinary - in design and installation are absolutely similar to the centers of the geodetic network, fundamental - are found as an exception.

Ground benchmarks: ordinary - in design and installation are absolutely similar to the GGS centers, fundamental - are a massive reinforced concrete monolith made immediately at the laying site right in the pit.

Since the fundamental benchmark can only be used for leveling I and II classes, a satellite benchmark is installed nearby, which is an ordinary benchmark, to which the mark from the fundamental benchmark is transmitted with class II accuracy and which is used instead of the fundamental one as a reference for leveling classes III and IV.

In Russia on Far East the Baltic system of heights is used. In the late 1980s, the mark of the Kronstadt footstock was transferred to the coast of the Far Eastern seas, the expected error was approximately 1 meter.

Types and designs of benchmarks, their manufacture and laying

The diverse physical and geographical conditions of the country determine different types benchmarks that correspond to certain areas.

A detailed description of the design of benchmarks, methods of their manufacture and laying is described in the "Rules for laying centers and benchmarks at points of geodetic and leveling networks", M., "Kartgeocenter" - "Geodesizdat".

Rock and wall benchmarks are included in the leveling lines of all classes one day after their laying, ground benchmarks on the leveling lines of III and IV classes - no earlier than 15 days after backfilling the pit.

In the permafrost distribution zone, ground benchmarks laid by drilling and thawing of soil are included in leveling not earlier than two months after their laying, and by excavation - in the season preceding leveling.

On leveling lines of classes I and II, ground benchmarks, as a rule, are laid a year before leveling.

To reduce or eliminate corrosion metal parts benchmarks should be used, if possible, galvanized or enameled pipes. In their absence, an anti-corrosion coating is applied to metal pipes. An anti-corrosion coating is also applied to the surface of concrete benchmarks if they are laid in a particularly aggressive soil environment. To reduce the effect of frost heaving, the outer surfaces of the benchmarks laid in the ground must be covered with anti-heaving agents. Benchmarks are protected in accordance with the requirements federal law"On Geodesy and Cartography" and "Regulations on Protected Zones and Protection of Geodetic Points on the Territory of the Russian Federation", approved by Decree of the Government of the Russian Federation N 1170 of October 7, 1996

Benchmarks are subject to inspection on the ground within the time limits stipulated normative documents Roskartografiya for the survey and restoration of points of geodetic and leveling networks. stable, incompressible rocks.

Centuries-old benchmarks can be rocky and unpaved. The types of age-old benchmarks depend on the depth of the rock. The safety of the age-old benchmark is ensured by the quality of the bookmark, the quality factor of the materials from which it is made, as well as the location and external design.

If the rock is at a depth of up to 120 cm, then a group of four rock benchmarks of the 173k type (Fig. 1, a) is laid, located at a distance of 25-50 m from each other. The heights of adjacent benchmarks must differ from each other by at least 15 cm.

The benchmark consists of a grade (stainless steel or bronze) and a concrete well with a lid. The dimensions of the well depend on the depth of the rock. When the rock comes out to the day surface, the external dimensions of the well are 50x50 cm. If the depth of the rock is 50 cm or more, this is a well with a diameter of 100 cm.

When the rock lies at a depth of 120 to 500 cm, a century-old benchmark of type 174k is laid (Fig. 1, b), which consists of a pylon (granite or high-quality concrete) with a parallelepiped shape and a cross section of 35x35 cm, a concrete slab (anchor) with dimensions of 100x100x40 cm and a well with a diameter of more than 100 cm.

IN upper part the pylon at a distance of 20 cm is cemented by two grades (horizontal and vertical).

The upper end of the pylon is located at a depth of 100 cm from the ground. A concrete slab is made at the place of installation of the benchmark and the third brand is cemented into it.

Before backfilling the pit with soil and installing the well, the excesses between all grades are measured with an accuracy of 1 mm.

The benchmark in the well is covered with gravel, and at a distance of 100-150 m from it, a fundamental benchmark with a satellite is installed.

A century-old tubular benchmark of type 175k (Fig. 2) is laid at the occurrence of incompressible rocks at a depth of more than 500 cm.

The benchmark is laid in a well with a diameter of ~25 cm.

It consists of a metal pipe with a diameter of 8-15 cm with a wall thickness of at least 1 cm, buried in incompressible rocks by 120 cm.

The reference pipe ends with a steel tip at least 250 cm long with three anchor disks.

The reference pipe with the help of concrete poured into the well is fastened to incompressible rocks.

The reference pipe is located in a protective pipe with a diameter of 16-23 cm with a wall thickness of at least 1 cm. In the lower part, the reference and protective pipes are separated by an oil seal and bitumen, in the upper part - by a rubber diaphragm and bitumen. At the upper end of the reference tube, at a distance of 20 cm from each other, two marks of a slightly oxidizing material (horizontal and vertical) are strengthened. The upper end of the benchmark is located at a depth of 100 cm from the surface of the earth. A fundamental benchmark with a satellite is laid next to the century-old benchmark at a distance of 100-150 m.

Fundamental benchmarks

Fundamental benchmarks, depending on the laying conditions, are divided into ground benchmarks (reinforced concrete, asbestos-cement, tubular metal) and rock ones.

Fundamental benchmark type 161 op. a sign (Fig. 3) for the area of \u200b\u200bseasonal freezing of soils is made in a pit. A reinforced concrete pylon measuring 30x30 cm is integral with a concrete slab (anchor). Grades made of low-oxidizing material (bronze, stainless steel) or cast-iron grades with hemispherical liners made of low-oxidizing material are cemented into the upper faces of the pylon and slab.

It is allowed to replace the reinforced concrete pylon with an asbestos-cement pipe with an outer diameter of at least 25 cm. A metal frame is installed inside the pipe and filled with concrete.

To increase the connection of the base of the asbestos-cement pipe with the anchor at a distance of 15-20 cm from the base, two mutually perpendicular rods with a diameter of 1.0-1.5 cm and a length of 60 cm are inserted before the pipe is filled with concrete. The upper face of the concrete slab is placed 60 cm below the boundary of the largest soil freezing, and the upper part of the pylon - 100 cm below the ground.

Above the benchmark, at a depth of 30 cm from the surface of the earth, an identification mark is laid. concrete slab 30x30x10 cm in size. The benchmark is made in a pit, the depth of which corresponds to the depth of the upper edge of the slab. For a concrete slab (anchor), they dig a recess in the soil of natural density. To do this, a tetrahedral recess is made at the bottom of the pit, the side walls of which are expanded downwards (Fig. 3).

The dimensions of the slab with vertical side faces are 115x115x40 cm. sign and 114 op. the sign is shown in Fig.4. If the rock comes to the earth's surface or lies at a depth of up to 130 cm, then two grades with a height difference of more than 100 mm are cemented into it at a distance of more than 500 cm from each other. In the event that stamps cannot be pawned on different height, then only one brand is laid, next to which a concrete slab is installed on a cement mortar with a second brand. When the rock lies at a depth of more than 130 cm, then a reinforced concrete pylon with a slab (anchor) is cast on it. The dimensions of the slab are 80x80x30 cm. Marks made of low-oxidizing material are placed in the upper faces of the pylon and the slab. The pylon is cast in such a height that its upper face is located 100 cm below the surface of the earth.

Fundamental rock benchmarks in the area of permafrost soils are laid of the same types as in the area of seasonal freezing, but the length of the reinforced concrete pylon should be such that its upper plane is at ground level. If the rock lies at a depth of up to 50 cm from the surface of the earth, then a mark is laid in the rock. The mark is closed with collapsible rock slabs, without soil admixture. In hard-to-reach areas, the pylon can be replaced with an asbestos-cement pipe with an outer diameter of at least 25 cm. The pipe is filled with concrete and securely fastened with metal frame with reinforced anchor anchor.

For the manufacture of a benchmark in the area of permafrost, quick-setting cement and additives that accelerate the setting of concrete are used. If at the time of laying the benchmark the surface of the rock has negative temperature, then before casting the anchor, the concrete and the rock are heated.

The excess between the main and additional grades of the fundamental benchmark is determined with an accuracy of 1 mm. The fundamental ground benchmarks for the northern zone of the permafrost region with a thawing depth of up to 150 cm are similar to ordinary soil benchmarks, but the base of the benchmark is located 400 cm below the thawing boundary. The fundamental benchmarks at a thawing depth of 150 cm or more are the same as in the area of seasonal freezing of soils, but their pylons are made so long that its upper part is at ground level. The base of the benchmark is located 1 m below the boundary of the greatest thawing of the soil, but not less than 250 cm from the surface of the earth. The reinforced concrete pylon of the benchmark can be replaced by an asbestos-cement pipe with an outer diameter of at least 25 cm. Using a metal frame, the pipe is fastened to the anchor of the benchmark and filled with concrete.

If permafrost soils are not found during the work, then the depth of laying the benchmark is increased by 50 cm, and the upper end of the pylon with the mark is placed (due to this increase) 50 cm below the ground surface. It is not allowed to lay fundamental metal tubular benchmarks in the pit and use metal anchors instead of concrete ones in all regions of the country.

Ground and wall benchmarks

permafrost benchmark identification soil

Ground benchmarks types 160 op. sign and 162 op. the sign (Fig. 5, 6) in the area of seasonal freezing of soils, as a rule, is laid in drilled wells with a diameter of 50 cm. Ground benchmark consists of a reinforced concrete pylon in the form of a parallelepiped with a cross section of 16x16 cm and a concrete slab (anchor) with a diameter of 48 cm, manufactured in advance. It is allowed to use plates square section size 50x50 cm.

A mark should be cemented into the upper face of the pylon (Fig. 7). In the middle of the concrete slab, a recess is made 20x20x15 cm in size, into which a reinforced concrete pylon is installed. The pylon can be replaced by an asbestos-cement pipe with an outer diameter of at least 16 cm, filled with concrete with reinforcement. A brand is inserted into the upper face of the pipe.

When using an asbestos-cement pipe, to increase the connection of its base with the anchor, two mutually perpendicular rods 1.0-1.2 cm thick and 25 cm long are inserted at a distance of 7-10 cm from the pipe base.

When installing the pipe in the anchor hole, the ends of the rods are placed in the corners of the recess. In the southern zone of the region of seasonal freezing of the soil, concrete slabs (anchors) 20 cm high are used, in the northern zone - 35 cm. The border between these zones runs along the Valuyki-Rossosh-Kamyshin-Pallasovka line.

It is allowed to lay benchmarks in wells with a diameter of 35 cm, but in this case the height of the concrete anchor in the southern zone should be 50 cm, in the northern zone - 80 cm.

The upper edge of the concrete slab (anchor) of the leveling benchmark I, II, III and IV classes should be 30 cm below the depth of the greatest freezing of the soil, regardless of the diameter of the well. All bench marks must be 50 cm below the ground. It is allowed to manufacture an anchor by pouring liquid concrete into the well.

The depth of the well is the same as when laying the benchmarks made in advance. Concrete is poured into wells with a diameter of 50 cm, respectively, by 20 or 30 cm, and into wells with a diameter of 35 cm - 30 or 70 cm. A pylon or asbestos-cement pipe is inserted into the concrete solution. The length of the pylon or pipe must be such that the mark falls at a distance of 50 cm from the ground.

It is possible to fill the wells with soil without waiting for the anchor concrete to set, provided that a layer of sand (loose soil) with a thickness of at least 10 cm is backfilled onto the liquid concrete.

It is allowed to replace reinforced concrete pylons with metal pipes with a diameter of 6 cm with a wall thickness of at least 0.3 cm or with a rail section (Fig. 6).

In this case, a concrete slab (anchor) and a pipe (rail) are fastened together at the place of manufacture of the benchmark. The metal pipe should have four pins protruding from it by 10 cm.

When laying benchmarks at the bottom of a well or pit, a layer of cement mortar with a thickness of at least 3 cm is poured under the base of the slab.

Reinforced concrete benchmarks laid in aggressive soils are made of dense concrete.

In areas of moving sand, benchmarks of type 15 are used (Fig. 8), which are screwed into the ground to a depth of at least 400 cm. The benchmark consists of a galvanized pipe, the upper end of which with a mark is placed 80 cm above the ground. A protective plate is attached to the pipe. Digging ditches in this case is prohibited.

In wetlands, the leveling lines are fixed with soil tubular benchmarks using pipes with a diameter of 6 cm with a wall thickness of at least 0.3 cm. A screw anchor with a diameter of at least 15 cm or a drilling spiral tip (auger, coil) with a diameter of at least 10 cm and a length of at least 50 cm.

The pipe is screwed to such a depth that the screw anchor enters the underlying water-saturated layer of dense rock by at least 150 cm, but in all cases the depth of the benchmark should not be less than the depth of the greatest freezing of the soil plus 100 cm. In the presence of mechanisms of shock-vibration action on in wetlands, it is possible to lay benchmarks consisting of several drill rods or pipes screwed together with a diameter of 4-6 cm with a wall thickness of at least 0.3 cm.

A metal cone is welded to the lower end of such a benchmark. The rods (pipe) are driven into the ground to such a depth that the cone enters the rock underlying the water-saturated layer by at least 300 cm. The upper end of the rod (pipe), to which the mark is welded, is located 30 cm below the ground surface.

The moment of entry of a screw anchor (spiral tip or cone) into a dense underlying water-saturated rock layer is determined by a sharp slowdown in the rate of sinking of the benchmark into the ground. They build around the benchmark wooden frame 200x200 cm in size and 50 cm high, filled with peat or mineral soil. A metal identification pole 100 cm long with a security plate is installed in the log house.

In the northern and middle zone of the permafrost area, tubular metal benchmarks of type 150 are laid in drilled or thawed wells (Fig. 9). Metal pipes are used as a benchmark. The pipe diameter is 6 cm, the wall thickness of the pipe is not less than 0.3 cm.

A brand is welded to the upper end of the pipe, and a multi-disk anchor is welded to the lower end, consisting of a metal disk and eight half-disks 0.5-0.6 cm thick and 15 cm in diameter.

For better screwing (pressing) of the pipe into the ground, the metal disk has blades.

The pipe is not filled with concrete.

On the outer surface pipes are applied with an anti-corrosion coating and an anti-porous one, and only an anti-corrosion one on the inside.

With a soil thawing depth of up to 125 cm, the base of the benchmark is located 200 cm below the thawing boundary.

If the thaw depth is 125 cm or more, then the base of the benchmark should be 300 cm below the thaw boundary.

If there are stony inclusions in the soil that make it difficult to drill and thaw wells, tubular benchmarks of type 165 op. the sign (Fig. 10) is laid in the pits.

Instead of a multi-disk, a concrete anchor is made with a diameter of 48 cm and a height of 20 cm.

The base of the concrete anchor is placed 100 cm below the boundary of the greatest thawing of the soil.

For all benchmarks in the area of permafrost soils, the upper end of the pipe with a welded mark is placed at the level of the ground surface.

In the southern zone of the permafrost region, the boundary runs along the Vorkuta-New Port-Khantayka-Suntar-Olekminsk-Aldan-Ayan line, only tubular benchmarks with concrete anchors are laid. If permafrost soils are not found during the work, then the depth of laying the benchmark is increased by 50 cm and the upper end of the pipe with the mark is placed (due to this increase) 50 cm below the ground surface.

It is forbidden to use metal anchors instead of concrete anchors in the southern zone of the permafrost region.

In a rock located on the surface or lying at a depth of up to 70 cm, a soil benchmark of type 9 op. sign (Fig. 11), which consists of a mark on the cement mortar. A reinforced concrete or tubular identification pole with a security plate is installed 100 cm from the benchmark. Identification pole is fixed in the rock cement mortar applied anti-corrosion coating and painted. Around the identification pillar and above the benchmark, if it is on the earth's surface, they lay out a tour of stones 50 cm high and up to 1 m in diameter. If the rock lies at a certain depth, then the stamp is covered with rock, and then the tour is laid out.

If the rock lies at a depth of more than 70 cm, then a benchmark of type 176 op. sign (Fig. 11). A reinforced concrete pylon with a slab (anchor) is installed on the rock. The pylon is cast in such a height that its upper face is 50 cm below the ground. In the area of permafrost soils, it is allowed to lay a tubular benchmark with a concrete anchor instead of a reinforced concrete rock benchmark.

If there is a sheer cliff near the benchmark at a distance of up to 50 m, then on it oil paint bright colors draw a triangle with sides of 100 cm, inside which indicate the number of the benchmark and the initial letters of the organization that performed the work.

In the walls of artificial structures, buildings and vertical surface rocks lay wall benchmarks of type 143 (Fig. 12, 13).

When making a wall benchmark and stamps (Fig. 7, 12, 13), the initial letters of the name of the organization that performed the leveling and the number of the benchmark are cast on the signs.

The wall benchmark shown in Fig. 12 is laid on the leveling lines of classes I and II, and the one shown in Fig. 13 is laid on the leveling lines of classes III and IV.

External design of benchmarks. The external design of the age-old benchmark consists of a reinforced concrete well with a protective cover and a lock; a mound made of stones; indicator monolith and a fence of four rail segments ( reinforced concrete pillars section 20x20 cm) with anchors laid to a depth of 140 cm and protruding 110 cm above the ground (Fig. 14).

It is allowed to use other external design, which ensures the reliable preservation of the age-old benchmark.

The design of the fundamental benchmark in the area of seasonal freezing of the soil consists of a rectangular ditch (Fig. 15) and a reinforced concrete identification pole (Fig. 16) with a guard plate (Fig. 17) with a thickness of at least 0.8 mm. The plate should be turned towards the benchmark. A mound 30 cm high with a diameter of 150 cm is made above the benchmark. The part of the identification pillar protruding above the ground is painted with oil paint of bright colors. The cross section of the ditch along the lower base is 20 cm, along the upper base - 120 cm, depth - 70 cm. The name of the organization and the reference number are signed on the identification pole with black paint (for example, Roskartografiya, 1274). A mound of stones 150x150 cm 70 cm high is laid out above the rocky fundamental benchmark.

The base of the identification pole is cemented with the rock or in the rock.

In the area of permafrost soils, the external design of the fundamental benchmarks is the same as that of the ground benchmarks, but in forested areas they put a tubular metal identification pole (Fig. 9 and 10), and within a radius of 100-150 m from the benchmark on trees at a height of 150-250 cm make ten marks with bright paint, which should look towards the benchmark. The external design of the ground benchmark (Fig. 18) is a ditch and an identification pole in the form of a reinforced concrete pylon with a slab (anchor) installed 80 cm from the benchmark. In forested areas it is allowed to install wooden identification poles.

The size of the lower base of the ditch is 20 cm, the upper one is 120 cm, the depth is 50 cm, the length is 1280 cm. A barrow 30 cm high with a diameter of 100 cm is poured over the benchmark. transverse section 16x16 cm. Plate diameter 48 cm, thickness 15 cm (Fig. 16).

The connection of the pylon with the plate is the same as that of the benchmark. The base of the slab is placed 80 cm below the ground. When using an anchor with a diameter of 34 cm, its height is increased to 25 cm, and the laying depth is up to 90 cm. A security plate is securely attached to the identification pole (when casting the pylon) (Fig. 17). The inscription on the plate is cast, stamped or applied by punching.

When installing the identification pole, the guard plate must be turned towards the benchmark.

The part of the identification pole protruding above the surface of the earth is painted with oil paint of bright colors (red, orange, yellow). Black paint on the pole indicates the number of the benchmark and the name of the organization that laid it. The identification pole may be tubular. Welded to the top of the pipe metal plate, to which a security plate is bolted. The pipe over the anti-corrosion coating is painted within the protruding part with bright-colored oil paint.

On the reverse side of the plate, the number of the benchmark and the initial letters of the organization that laid it are inscribed with black paint. A plug is welded to the upper end of the pipe.

The lower end of the pipe must have a concrete (metal) anchor with a diameter of 48 cm and a thickness of 15 (0.5) cm, buried in the ground by 100 cm. When using an anchor with a diameter of 34 cm, its height is increased to 25 cm, and the laying depth is up to 90 cm. The top of the tubular identification pole should be 100 cm above the ground.

In the forested areas of the permafrost region, as well as in the swampy areas of the region of seasonal freezing of soils, a log house is constructed above the ground benchmark from logs 200x200 cm in size, 50 cm high (Fig. 19).

The log house is filled with soil and moss, which are taken no closer than 15 m from the benchmark. In a log house above the benchmark set wooden pole 70 cm long, and next to it is a metal identification pole, within a radius of 100-150 m from the benchmark on trees at a height of 150-250 cm, ten marks are made with bright paint.

In the tundra, a mound 200x200 cm in size and 50 cm high is built of earth and moss above the benchmark. The mound is covered with a layer of turf. Above the benchmark, a wooden pole 70 cm long is installed, and next to it is an identification pole. Land, moss and turf are taken no closer than 15 m from the benchmark.

In the area of permafrost, depending on how the benchmark is laid, by drilling (thawing) or in a pit, an identification metal pole is installed at a distance of 100 or 70 cm from the benchmark (Fig. 9, 10). The lower end of the pipe must have an anchor, which is buried in permafrost soil by at least 50 cm. The upper part identification mark placed 100 cm above the ground and painted with oil paint in bright colors. Various mechanisms can be used for digging pits, drilling wells, driving piles and screwing pipes (Appendix 8). Documentation compiled upon completion of work on laying benchmarks:

a report with explanatory note; log bookmarks of benchmarks;

· a list of benchmarks and a diagram of their location (on the map of the largest scale);

· acts of delivery of benchmarks under supervision for safety;

photographs of buildings and rocks in which wall benchmarks are laid;

· maps at a scale of 1:25000 and larger, aerial photographs showing the locations of the laid and surveyed benchmarks, outlines. The scale of the outline is chosen in such a way that the nearest landmarks indicated in the description of the location of the benchmark fit on it. The outlines are compiled visually, according to maps, aerial photographs in the usual conditional topographic signs, horizontal lines are drawn on them conditionally, only to show the nature of the relief.

A separate document contains determination schemes and observation materials for the instrumental determination of the coordinates of fundamental, secular and ordinary benchmarks and a list of benchmark coordinates along the leveling lines.

The coordinates of secular and fundamental benchmarks determined by instrumental methods are given with an error of no more than 1.0 m, ordinary benchmarks and marks with an error of no more than 10 m.

Literature

1. Z.?.S?rsembekova, “?Aza? university» 2013

2. M.B.N?rpeisova, Astana 2009

3. Poklad G.G. Geodesy M: Nedra, 1988.

4. Neumyvakin Yu.K. etc. Geodesy. Topographic surveys M.: Nedra, 1991.

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Geodetic sign - a ground structure at a geodetic point, which serves to place a sighting device (sighting cylinder) and install a geodetic instrument (instrument). Sometimes it has a platform for the work of a specialist, and also indicates a geodetic point on the ground. The geodetic mark (surface structure) and the center of the geodetic point (underground structure) together constitute the geodetic point.

The geodetic sign is constructed only at the points of the trigonometric (planned) geodetic network (trigonometric point). Due to differences in detection technologies, at the points of the leveling (altitude) and gravimetric networks, the sign is not constructed and is not used.

An identification mark is installed near the center of the point at a certain distance - a metal or reinforced concrete pole with a security plate with the inscription: "Geodetic point, protected by the state." To ensure long-term preservation and fixation on the ground, the point has an external design, determined by the "Instruction on the construction of the state geodetic network", "Guidelines for the construction of geodetic signs" and other departmental documents. Depending on the type of terrain, this can be: a shaft of stones, a wooden frame, a trench with ditches, a mound, etc.

A geodetic sign can be wooden, stone, reinforced concrete or metal. In some cases, the sign may be constructed temporarily (collapsible, or transportable).

A geodetic sign can be in the form of a simple signal, a complex signal, a pyramid, a tour or a tripod, depending on the height to which it is necessary to raise the sighting target or device, and based on local conditions. In flat areas, signals and pyramids are most common, in mountainous areas - tripods and tours.

Benchmark (from French repère - mark, sign, starting point) in geodesy - a sign that fixes a certain point on the earth's surface with a known absolute height. This height is determined by leveling with respect to the original level surface. A metal disc with a diameter of 5 centimeters (stamp) with a number and an indication of the department is fixed on the benchmarks. In the Russian Federation, it is customary to calculate the heights of benchmarks relative to the zero mark of the Kronstadt footstock.

The fundamental benchmarks are reinforced concrete pylons. Such benchmarks are laid in the ground at a distance of 50 - 80 kilometers from each other on all leveling lines of the 1st class, the most important lines of the 2nd class and next to the main offshore water measuring installations. Another type of benchmarks are ordinary ones: they are laid after 5 - 7 kilometers on leveling lines of any class. Ordinary benchmarks, in turn, can be ground, which are installed in the ground, wall, which are laid in the walls of capital structures, and rock, which are laid in rocky soil. Finally, there are secular benchmarks, which are laid at the intersection points of the leveling lines of the 1st class.

Fundamental and ground benchmarks form the state leveling network on the territory of the country and are used in the study of the difference in sea levels, various survey works and as reference points for determining the heights of intermediate points on the earth's surface during topographic surveys.

In Russia, the Baltic system of heights is used in the Far East. At the end of the 1980s, the mark of the Kronstadt footstock on the coast of the Far Eastern seas was transferred, the expected error was approximately 1 meter.

Leveling mark - a point in the leveling network, which serves to fix a point, the height of which above sea level is determined by leveling. The stamp is a cast metal disk with a diameter of 8 to 10 centimeters, built into the wall of a permanent (usually stone) building or bridge. In the center of the disk there is a hole with a diameter of about 2 mm, which determines the position of the mark. Its number is cast on the stamp, as well as the name of the organization that carried out the leveling work.

Unlike a benchmark, a brand can be deformable.

In the Russian Federation, the height of the leveling mark (the hole in its center) is determined relative to the zero of the Kronstadt footstock, and is given in the relevant catalogs.

Deformation mark - a mark fixed on a part of the structure of a structure (foundation, column, wall), in order to measure the settlement, heel or shift of the foundation.

permafrost benchmark identification soil

Ground benchmarks types 160 op. sign and 162 op. a sign (Fig. 5, 6) in the area of seasonal freezing of soils, as a rule, is laid in drilled wells with a diameter of 50 cm. in advance. It is allowed to use square-section plates measuring 50x50 cm.

It is allowed to lay benchmarks in wells with a diameter of 35 cm, but in this case the height of the concrete anchor in the southern zone should be 50 cm, in the northern zone - 80 cm.

It is allowed to replace reinforced concrete pylons with metal pipes with a diameter of 6 cm with a wall thickness of at least 0.3 cm or with a rail section (Fig. 6).

In this case, a concrete slab (anchor) and a pipe (rail) are fastened together at the place of manufacture of the benchmark. The metal pipe should have four pins protruding from it by 10 cm.

When laying benchmarks at the bottom of a well or pit, a layer of cement mortar with a thickness of at least 3 cm is poured under the base of the slab.

Reinforced concrete benchmarks laid in aggressive soils are made of dense concrete.

The moment of entry of a screw anchor (spiral tip or cone) into a dense underlying water-saturated rock layer is determined by a sharp slowdown in the rate of sinking of the benchmark into the ground. A wooden frame 200x200 cm in size and 50 cm high is built around the benchmark, filled with peat or mineral soil. A metal identification pole 100 cm long with a security plate is installed in the log house.

A brand is welded to the upper end of the pipe, and a multi-disk anchor is welded to the lower end, consisting of a metal disk and eight half-disks 0.5-0.6 cm thick and 15 cm in diameter.

For better screwing (pressing) of the pipe into the ground, the metal disk has blades.

The pipe is not filled with concrete.

On the outer surface of the pipe, an anti-corrosion and anti-rock coating is applied, and on the inner surface only an anti-corrosion one.

With a soil thawing depth of up to 125 cm, the base of the benchmark is located 200 cm below the thawing boundary.

If the thaw depth is 125 cm or more, then the base of the benchmark should be 300 cm below the thaw boundary.

If there are stony inclusions in the soil that make it difficult to drill and thaw wells, tubular benchmarks of type 165 op. the sign (Fig. 10) is laid in the pits.

Instead of a multi-disk, a concrete anchor is made with a diameter of 48 cm and a height of 20 cm.

The base of the concrete anchor is placed 100 cm below the boundary of the greatest thawing of the soil.

For all benchmarks in the area of permafrost soils, the upper end of the pipe with a welded mark is placed at the level of the ground surface.

It is forbidden to use metal anchors instead of concrete anchors in the southern zone of the permafrost region.

In a rock located on the surface or lying at a depth of up to 70 cm, a soil benchmark of type 9 op. sign (Fig. 11), which consists of a mark on the cement mortar. A reinforced concrete or tubular identification pole with a security plate is installed 100 cm from the benchmark. The identification pole is fixed in the rock with cement mortar, an anti-corrosion coating is applied and painted. Around the identification pillar and above the benchmark, if it is on the earth's surface, they lay out a tour of stones 50 cm high and up to 1 m in diameter. If the rock lies at a certain depth, then the stamp is covered with rock, and then the tour is laid out.

If there is a sheer rock near the benchmark at a distance of up to 50 m, then a triangle with sides of 100 cm is drawn on it with oil paint of bright colors, inside which the benchmark number and the initial letters of the organization that performed the work are indicated.

Wall benchmarks of type 143 are laid in the walls of artificial structures, buildings and the vertical surface of the rock (Fig. 12, 13).

When making a wall benchmark and stamps (Fig. 7, 12, 13), the initial letters of the name of the organization that performed the leveling and the number of the benchmark are cast on the signs.

The wall benchmark shown in Fig. 12 is laid on the leveling lines of classes I and II, and the one shown in Fig. 13 is laid on the leveling lines of classes III and IV.

External design of benchmarks. The external design of the age-old benchmark consists of a reinforced concrete well with a protective cover and a lock; a mound made of stones; an index monolith and a fence of four sections of rail (reinforced concrete pillars with a section of 20x20 cm) with anchors laid to a depth of 140 cm and protruding 110 cm above the ground (Fig. 14).

It is allowed to use another external design that ensures the reliable preservation of the age-old benchmark.

The base of the identification pole is cemented with the rock or in the rock.

The size of the lower base of the ditch is 20 cm, the upper one is 120 cm, the depth is 50 cm, the length is 1280 cm. A mound 30 cm high with a diameter of 100 cm is poured over the benchmark. section 16x16 cm. Plate diameter 48 cm, thickness 15 cm (Fig. 16).

When installing the identification pole, the guard plate must be turned towards the benchmark.

The part of the identification pole protruding above the surface of the earth is painted with oil paint of bright colors (red, orange, yellow). Black paint on the pole indicates the number of the benchmark and the name of the organization that laid it. The identification pole may be tubular. A metal plate is welded to the upper part of the pipe, to which a security plate is bolted. The pipe over the anti-corrosion coating is painted within the protruding part with bright-colored oil paint.

On the reverse side of the plate, the number of the benchmark and the initial letters of the organization that laid it are inscribed with black paint. A plug is welded to the upper end of the pipe.

The log house is filled with soil and moss, which are taken no closer than 15 m from the benchmark. A wooden pole 70 cm long is installed in a log house above the benchmark, and next to it is a metal identification pole, within a radius of 100-150 m from the benchmark, ten marks are made with bright paint on trees at a height of 150-250 cm.

In the area of permafrost, depending on how the benchmark is laid, by drilling (thawing) or in a pit, an identification metal pole is installed at a distance of 100 or 70 cm from the benchmark (Fig. 9, 10). The lower end of the pipe must have an anchor, which is buried in permafrost soil by at least 50 cm. The upper part of the identification mark is placed 100 cm above the ground and painted with oil paint of bright colors. Various mechanisms can be used for digging pits, drilling wells, driving piles and screwing pipes (Appendix 8). Documentation compiled upon completion of work on laying benchmarks:

a report with an explanatory note; log bookmarks of benchmarks;
· a list of benchmarks and a diagram of their location (on the map of the largest scale);
· acts of delivery of benchmarks under supervision for safety;
photographs of buildings and rocks in which wall benchmarks are laid;
· maps at a scale of 1:25000 and larger, aerial photographs showing the locations of the laid and surveyed benchmarks, outlines. The scale of the outline is chosen in such a way that the nearest landmarks indicated in the description of the location of the benchmark fit on it. The outlines are compiled by eye, according to maps, aerial photographs in conventional conditional topographic signs, contour lines are drawn on them conditionally, only to show the nature of the relief.

Fixing the route in height

Lecture 14

14.1. Fixing the route in height

14.2. Leveling tasks

14.3. Work with the level at the station

14.4. Leveling ravines

14.5. Cross-section leveling

14.6. Leveling across the river

14.7. Track leveling control

14.8. Questions for self-control

Along the entire route broken on the ground, but outside the work area, points are fixed, called benchmarks. They can be temporary or permanent. Temporary benchmarks- these are pillars buried below the freezing depth. A cross is attached at the bottom. Such a benchmark is called temporary ground. As a temporary benchmark, you can use tree stumps with a diameter of 0.5 m or more. Temporary benchmarks are placed along the route every 2–3 km, and after 20–30 km they arrange permanent benchmarks. It is especially necessary to arrange them at the beginning and at the end of the route, at stations, near future bridges and tunnels. Permanent benchmarks can be wall or ground.

Benchmark (from French repere - sign, starting point) - a sign that fixes a point on the earth's surface, the height of which relative to the original level surface is determined by leveling.

In the Russian Federation, the heights of the benchmarks are calculated relative to the zero of the Kronstadt footstock. The benchmarks of the state leveling network serve as initial (reference) points for determining the heights of intermediate points on the earth's surface during topographic surveys and various kinds of survey work, and are also used for scientific purposes when studying the difference in sea levels.

Benches according to their importance are divided into:
1) secular 2) fundamental 3) ordinary

Centuries-old benchmarks are distributed throughout the country, according to a special scheme, in places established by the instructions, mainly for scientific purposes. The depth of the bookmark is determined by the occurrence of rocks.

The fundamental benchmarks, which are reinforced concrete pylons, are laid into the ground every 50-80 km on all leveling lines of the 1st class, as well as on the most important lines of the 2nd class and near the most important offshore water measuring installations.

Ordinary benchmarks, laid after 5-7 km on leveling lines of all classes, are divided into ground, installed in the ground, rock (fixed in rocks) and wall, laid in the walls of capital structures. In hard-to-reach areas, the distance between benchmarks can be increased to 6-7 km, and in seismically active areas it should be reduced to 3-3.5 km.

Wall anchors are fixed in the built-up area wherever possible. Fastening is carried out in the bearing parts of stone or concrete structures at a height of less than 0.3 m using leveling marks.

1. GROUND REPER
Ground benchmarks must be placed mainly within dry areas composed of draining sandy and coarse-grained soils. It is not allowed to lay benchmarks on landslide slopes and sites with the presence of solifluction phenomena or underground ice,
When constructing permanent ground benchmarks in areas with heaving soils of the active layer (clayey, silty sands, etc.), it is necessary to pay attention to ensuring the stability of the benchmarks. Special attention. To reduce the impact of heaving soil, the upper part of the benchmark within the active freezing - thawing layer is made of a reduced section or the top of the benchmark is placed below the soil surface. The lower part of the benchmark, placed in permafrost or thawed soil, is made with dimensions that ensure the stability of the benchmark from buckling (Fig. 1).

Rice. 1. Scheme of the device of a soil benchmark for use in areas with merging permafrost:
1 - perforated pipe of the benchmark; 2 - wooden cork; 3 - peat or moss; 4 - local soil; 5 - surface of permafrost soil after installation of the benchmark

When using tree stumps as benchmarks, it must be taken into account that they are subject to alternating seasonal movements as a result of the impact of heaving soils.
The ground benchmark, intended for laying in areas with shallow permafrost soil (see Fig. 1), is metal pipe with an outer diameter of approx. 60 mm and with a wall thickness of at least 3 mm

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