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What do you need shafts. Shafts - what is it? Pit device

First of all, the customer must understand that without extracting the pits and inspecting the foundation structures, the surveyors can draw conclusions about the state of the foundations of the building only by indirect signs. Holes are needed in order to:

establish the type of foundation, its shape in plan, dimensions, depth, previously made reinforcements, as well as grillages (when examining pile foundations in each pit, their diameter, pitch and average number per 1 m of foundation are measured) and artificial foundations;
examine the foundation material with the definition of the class of concrete, grade of stone and mortar, and sometimes to open the reinforcement of the foundation;
take samples of soil and foundation material for laboratory testing;
establish the presence of waterproofing and determine its condition.

According to SP 11-105-97 "Engineering and geological surveys for construction. Part I. General rules for the production of work", a pit is a mine working with a maximum depth of up to 20 meters. However, we will set aside the official definitions, since the survey is a more narrowly focused type of activity and has its own characteristics. In the survey, the depth of pits of 20 m can only be found on unique structures and the customer should not take the picture of terrible destruction to heart. The average depth of a pit in an average building for an average customer, based on our practice, is about 2 meters if the pits are torn off from the unheated side of the building, and even less if the pit is torn off from the basement.
In the survey of buildings, the pit is a vertical excavation in the ground with a depth of 0.5 meters below the base of the surveyed foundation, which is torn off next to the wall or column of the building. The dimensions of the pit in the plan are determined by the size of the base of the foundation, its shape, as well as the properties of the soil (when the soil is shedding, it is usually easier and more profitable for workers to dig a larger pit than to strengthen its walls with boards). Most often, the depth of the pit is not more than 2 meters, the dimensions in terms of 1.5x1.5 meters from the outside of the building, and the depth is up to 0.8 meters, the size in terms of 1x1 m from the basement of the building.
Strip foundations are opened directly along the sheer edge of the wall. Pillar foundations should be opened by one of the following three methods given in the Manual for the inspection of building structures of buildings of OJSC "TsNIIPromzdaniy" (see figure):

The number of pits depends on the availability of documentation, the space-planning and structural design of the building, on the condition of the building (presence of sedimentary deformations), and on the purpose of the survey. For example, according to MRR 2.2.07-98 "Methodology for examining buildings and structures during their reconstruction and redevelopment", control pits for examining the structure, dimensions and material of foundations arrange 2-3 pits per building, the pits are torn off from the outside or inside, depending from the convenience of opening them. In reality, it is usually necessary to lay much more pits, and when they are separated, sometimes one or two pits turn out to be useless due to an obstacle encountered in the form of an old foundation, communications not indicated anywhere, a large boulder or piece of concrete. Surprisingly often, in a small, but repeatedly reconstructed building, it is necessary to lay much more pits than in a huge workshop with the same type of structures - this fact is sometimes difficult to substantiate to the customer, but without comprehensive data on the design of the foundations, the analysis of the work of building structures will be flawed initially. When there is a design, and even more so as-built documentation for a building, the number of pits can be reduced, provided that the control pits show full compliance with the actual design of the foundations to the project and in the absence of sedimentary deformations in the building - alas, sometimes it happens that the only one of several control pits reveals complete the discrepancy between the foundations and the project and even the previous survey of the building (there are hacks among the builders and among the surveyors), and then you have to upset the customer with additional work with the appropriate estimates. It is also important for excerpts of pits to have a technical assignment for a survey from designers or coordination of pitting sites with them - after all, designers initially understand which structures will be loaded as a result of the project, and also know which places they need to check when designing an extension. When assigning the number of pits and their locations, the examiners take into account the following factors:

the structural scheme of the building, the number of different types of differently loaded load-bearing structures, the possibility of opening several foundations with one pit - ideally, it is necessary to have information about the foundations of all different different structural elements;
the state of the building structures, blind areas, the presence of sedimentary deformations - it is advisable to lay a pit near sedimentary cracks in order to see the state of the foundation in a critical place;
availability of design, executive or survey documentation;
availability of technical specifications from designers;
the presence of a technical assignment from the customer (the customer may have his own ideas about the reconstruction of the building, well, he can simply know where in the building, in his opinion, there are significant sedimentary cracks);
the possibility of extracting pits from the outside of the building without the consent of the supervisory authorities - approvals will take more time than survey work (either long or expensive), therefore, alas, where possible, pits are most often torn off without permits, that is, illegally (also therefore, the pits are easier to tear off from the inside of buildings);
availability of documentation, information on underground communications from the operating service, the customer, the presence of inputs to the building of communications after a preliminary inspection - the layout of the pits must be agreed with the operating service or with the customer;
weather conditions, the presence of drainpipes, slopes - it is difficult to tear off the pits and examine the foundations in conditions of constant flooding, and it is dangerous to flood the basement (well, in winter it will be much more expensive to hammer frozen ground for the customer);
basement operating conditions, floor construction and basement finishing, blind area construction - to compare the complexity of restoring structures and performing earthworks and works on opening hard coatings;
minimizing the volume of earthworks - this factor is one of the least significant.

As you can see, to develop a scheme for drilling an object, an analysis of many factors is required. Moreover, after analysis, it sometimes turns out that it is completely or partially impossible to excavate the foundation for a particular structure without significant costs and inconvenience for the customer (for example, the internal walls of warehouses or factories with fragile or sterile products in the basement or on the first floor). It is also obvious that the development of a survey program and a commercial offer based on it without a site visit (and this is required by 99% of customers already at the first telephone conversation) is nothing more than a convention, which means that there is a high probability of additional work or lack of information obtained during the survey. Based on our practice, we can say that at least 4-5 pits come off in the average surveyed building, most of them from the basement, most of the pits are laid in the corners at the junctions of walls and columns. With rare exceptions, the pits are torn off by hand, because if there is any of the most remarkable documentation for the location of communications inside and outside the building, according to Murphy's law, an element of communications is necessarily detected during the passage - and therefore, for excerpts of the pits, certain qualifications and experience are also required from the pit worker.

What negative factors entails a passage of pits for the customer - you should know about these inconveniences in advance:

noise when opening the blind area, the concrete floors of the basement, the first floor with the help of a chipper, cutting the reinforcement with the help of a grinder - this does not allow working outside at night if the object is located near residential buildings;
dust of small fractions when opening hard coatings (blind areas, floors, finishes), dust when extracting a pit;
humidity when extracting a pit from inside the building, the need to ventilate the basement;
the probability of flooding the basement with precipitation when opening the pits outside the building - this does not mean that it will definitely flood (in our practice this has not happened yet), but the probability of flooding with improper covering of the pit and water drainage, as well as with excess precipitation or strong wind increases;
damage to the blind area when extracting the pits from the outside - for a length of about 1.5-2 meters and for the entire width of the blind area is dismantled (a rare exception is bypassing a well-reinforced narrow blind area and extracting the pit under it);
damage to the floors of the basement or the first floor of the building and the wall decoration adjacent directly to the pit;
damage to the waterproofing layer of foundations or floors of the building;
the impossibility of operating the premises in the place of excerpts of pits until they are completely sealed;
the need to restore finishing coatings, blind areas.

In our practice, as a rule, we tear off the pits with the help of our workers, since sometimes (despite the experience of the workers) the direct guidance of an engineer is required so that the pit is passed to the base of the foundation (an engineer is already working below) and that excess soil is not removed from under soles, which threatens with deformations of the foundation, as well as to prevent damage to the foundation structure. The presence of an engineer during the flooding of the pit is especially important for a quick inspection, since the subsequent open pumping of water from the pit is not always permissible and is fraught with additional sediments of the foundation if dusty soil particles are washed out from under the sole (if any). After driving the pit, the engineer takes measurements, if necessary, makes openings of the waterproofing and structural layers, removes samples of materials. Backfilling of pits is usually also carried out by our own forces, with soil compaction by manual rammers or watering. After backfilling the pit, it is recommended to let the backfill soil settle down and compact (if outside, wait until the ground thaws and the soil is washed with precipitation), and then proceed to seal and restore the blind area or floor structures. Restoration of the blind area or floor is usually carried out by the customer - if this is done by the survey organization, then, as a rule, a subcontractor appears to carry out these construction works, and the customer simply overpays. If the customer has workers, he may well organize the excavation and backfilling of the pits on his own - this will reduce the cost of survey work.

We recommend that the customer treat with understanding and patience the need to excerpt the pits, since this is an important type of work on the inspection of the building. The more detailed the building is examined, the less likely it is that problems will arise during its reconstruction or operation. And sealing the basement floor or restoring the blind area is not a big problem. The inconvenience associated with extracting the pits usually lasts no more than 1-1.5 weeks.

Dmitry Kuznetsov,

Exploration workings are carried out to determine the geological structure and hydrogeological conditions of the site intended for construction, establish the type and condition of rocks, take rock samples and groundwater samples.

The main exploration workings include clearings, ditches, adits, pits and boreholes.

Clearings, ditches and adits are classified as horizontal workings. With a slightly inclined and horizontal occurrence of layers, pits and boreholes are laid.

Clearings are workings used to remove a layer of loose deluvium or eluvium from inclined surfaces of natural outcrops.

Ditches are narrow (up to 0.8 m) and shallow (up to 2 m) workings, performed manually or with the help of equipment in order to expose bedrock.

Adits are underground horizontal workings laid on slopes and revealing rock strata in the depths of the massif. The walls of the adit, as a rule, are fastened.

Shafts - well-shaped vertical workings of a rectangular (or square) section. A round pit is called a "pipe". Penetration of pipes is easier to mechanize, but it is easier and more accurate to determine the position of the formation in space using rectangular pits.

The pits help to study in detail the geological structure of the site, to take samples of any size while maintaining their structure and natural moisture. The disadvantage is the high cost and laboriousness of excavation of pits, especially in water-saturated soils. It should be noted that recently there have been special digging machines that allow you to pass round pits, for example, the KShK-30 machine, which allows you to make workings with a diameter of up to 1.3 m and a depth of up to 30 m.

The size of the pits in the plan depends on their intended depth. The diameter of the pipes usually does not exceed 1 m.

The pits are drilled by deepening the face and ejecting soil to the surface, first with a shovel, then with the help of simple lifting mechanisms. As the walls of the pits deepen, it is necessary to strengthen them, otherwise they may collapse.

The nature and method of fastening depends on the stability of the rocks. If the pipes tend to pass through stable rocks and fastening is usually not required for them, then for rectangular pits in loose soils, driven fastening is used, in weak soils in the absence of water (or weak inflow) - spacer and in water-saturated soils or deep pits - log fastening.

As the pit passes, documentation is continuously kept - data on the rocks being opened, the conditions of their occurrence, the appearance of groundwater are recorded in the pit log; take samples. On all four walls and the bottom, they make a sketch and draw up a scan of the pit. This makes it possible to more accurately determine the thickness of the layers and the elements of their occurrence.

At the end of the reconnaissance work, the pits are carefully filled up, the soil is compacted, and the surface of the earth is leveled.

Boreholes are round vertical or inclined workings of small diameter, performed by a special drilling tool. In boreholes, a mouth, walls and a bottom are distinguished.

Drilling is one of the most important types of exploration work; it is mainly used to study horizontal or gently dipping seams. With the help of drilling, they find out the composition, properties, condition of soils, and the conditions for their occurrence. All this work is based on the study of rock samples that are continuously extracted from the well as it deepens during the drilling process. Depending on the drilling method and rock composition, the samples may be of undisturbed or disturbed structure. The samples obtained by drilling are called core.

The advantages of drilling include: the speed of well completion, the possibility of reaching great depths, the high mechanization of work, the mobility of drilling rigs. Drilling has its drawbacks: the small diameter of the wells does not allow for inspection of the walls, the size of the samples is limited by the diameter of the well, and it is impossible to determine the elements of the occurrence of layers from one well.

In engineering and geological research, the following types of well drilling are used: manual percussion-rotary, rotary core, vibration, auger. In all cases, drilling is carried out with a drill bit (drill), which, when connected to drill pipes (rods), creates a drill string. The impact or rotation of this projectile, or both, is carried out by drilling rigs driven by various engines (mechanical drilling), or by hand drilling. The latter method is used in low-strength rocks and for shallow drilling.

The type of drill bit depends on the strength and characteristics of the rock. So, for example, chisels and crowns are used for rock penetration. The rock is crushed with a chisel, it is extracted to the surface in the form of crushed stone. With the help of crowns with hard alloy teeth caulked in them, an annular gap is produced in the bottom of the wells, and the sample takes the form of a cylinder. In softer rocks, the same work is performed by a hollow toothed cylinder 1-3 m long, inside which the rock remains in the form of a core or column. Hence the name of this type of drilling - rotary core drilling. In clay rocks, tips of a special design are used - soil carriers, with a diameter of at least 100-125 mm. This makes it possible to obtain soil samples with an undisturbed structure in the form of monoliths.

In recent years, the vibratory drilling method has been used, i.e. drilling using a vibrator to immerse the drill string into the bottomhole rock. With the help of a vibro-drill, you can pass bulk soils, soft clay marls and many other sedimentary rocks, but it should be remembered that clay soils change their physical state. When vibrodrilling, it is impossible to fix the level of groundwater.

Screw drilling. Augers are special rods on the surface of which a steel spiral is wound. The augers are connected into a drill string, forming a continuous screw conveyor for extracting soil from the well.

The destruction of the face and the rise of soil to the surface occur simultaneously. This type of drilling allows you to pass wells with a diameter of 150 to 1500 mm.

Auger drilling is applicable only in some loose rocks, such as loess loams. This method has a high penetration rate, but has a number of disadvantages: it is difficult to determine the boundaries of various layers, to establish the level of groundwater, the samples have a broken structure.

Drilling wells in weak and water-saturated rocks is difficult due to collapse and slumping of the walls. For their fastening, steel casing pipes are used, which are lowered into the wells, after which they continue drilling with a tip of an already smaller diameter.

Drilling documentation is carried out by keeping a brown log, where all data on drilling and sampling are entered. A well drill string is compiled on a scale from 1:100 to 1:500.

After completion of drilling operations, the wellhead is covered with compacted soil.

At the construction site, the uninitiated can hear many new terms. One of these terms is - pit. Let's see what it is?

What is a shurf?

A pit is an ordinary pit for inspecting the foundation and (or) soil base, as well as for taking soil samples during geological surveys. Actually, the work of digging holes is called - pitting.

Now let's answer common questions about drilling.

What are the dimensions of the pit in the plan are usually?

The size in terms of the pit should be such that it is convenient for the specialist to carry out all the necessary work in the pit. In the pit, it should be convenient to squat down, bend over for sampling, etc. If the existing foundations are shallow (laying the foundation below the ground up to 50 ... dig deeper, it is rational to expand the pit to a size in terms of 1x1 m.

What should be the depth of the hole?

The depth of the pit is taken from the following considerations:

If the pit is made directly near the existing foundation, then it is made to the base of the foundation (where the foundation rests on the soil base). Sometimes, to measure the width of the sole of the existing foundation, the pit is made deeper - below the sole of the foundation by 10 ... 20 cm ( Attention! It is possible to deepen the pit below the base of the foundation if the foundation is in a satisfactory condition and is a sufficiently cohesive, monolithic structure).
If the pit is made before the start of new construction, then it is carried out to the design depth of the future foundation.

It should be noted that if the pit is made deep in loosely cohesive soils (for example, sandy soils), then either slopes should be performed or the soil should be fixed with wooden shields.

Where should the hole be made?

In any case, before pitting, you should consult on this topic with a specialist, that is, with the one for whom these pits are performed. But in general, you can consider the following rules:

if there is a basement in the building, the pits should be made in the basement (outside, the pits will be very deep);
in the absence of basements, pits can be performed both outside and inside the building;
if possible, pits should be placed at the intersection of two main walls (in this case, when using one pit, it is possible to inspect the foundations immediately under two walls);
during new construction, they try to carry out the pits in close proximity to the building spot.

How many holes to make?

The number of pits is determined by a civil engineer who performs a survey of building structures or a geologist who conducts engineering and geological surveys.

I hope you now understand the concept pit and began to better understand the builders.

If you need advice on this, you can contact me at .

You were advised by an expert

Ismagilov Andrey Olegovich

Pit

Derrick cellar, pit

A vertical or inclined mine working of small depth (up to 25 m), passable from the earth's surface for exploration of minerals, ventilation, drainage, transportation of materials, lowering and raising people, and for other purposes. When drilling oil and gas wells, the pit is used to lower the kelly during the build-up of drill pipes and during periods when it is not being produced. Under the pit, they drill with a turbodrill or a rotor.

Brief electronic reference book on the main oil and gas terms with a system of cross-references. - M.: Russian State University of Oil and Gas. I. M. Gubkina. M.A. Mokhov, L.V. Igrevsky, E.S. Novik. 2004 .

Synonyms:

See what "Surf" is in other dictionaries:

pit- hole, and ... Russian spelling dictionary

pit- shaft / ... Morphemic spelling dictionary

SHURF- (German Schurf). Deepening for finding or researching already found mineral masses. Dictionary of foreign words included in the Russian language. Chudinov A.N., 1910. Schurf German. Schurf. Deepening in the ground for exploration of ore. Explanation of 25000… … Dictionary of foreign words of the Russian language

pit- a; m. [it. Schurf] Spec. A vertical or inclined mine working for mineral exploration, ventilation, blasting, etc., passing directly from the surface of the earth and having a shallow depth. Break through, lay sh. Exploration, ... ... encyclopedic Dictionary

Pit- vertical mining of a square or rectangular section, carried out from the surface of the Earth in the search and exploration of minerals, as well as in geol. survey, engineering geol. and hydrogeol. research, etc. The depth of Sh. can be ... ... Geological Encyclopedia

SHURF- SHURF, pit, husband. (German: Schurf) (horn). Vertical mining for exploration of mineral deposits. Explanatory Dictionary of Ushakov. D.N. Ushakov. 1935 1940 ... Explanatory Dictionary of Ushakov

SHURF- SHURF, a and a, pl. s, ov and s, ov, husband. (specialist.). Shallow vertical or inclined mine working for mineral exploration, for blasting. Explanatory dictionary of Ozhegov. S.I. Ozhegov, N.Yu. Shvedova. 1949 1992 ... Explanatory dictionary of Ozhegov

SHURF- husband. shirf, mountain reconnaissance pipe, pit, digging: a well of torture, for reconnaissance of deposits and finding ores and others. fossils. Hit the pit, beat the pits, and shu (and) rf, do exploratory excavations; sya, suffering. Drilling and drilling, action according to Ch. vshchik ... Dahl's Explanatory Dictionary

Pit- (German Schurf) vertical (rarely inclined) mining of shallow depth (up to 40 m), passable from the earth's surface for exploration of minerals, ventilation, drainage, transportation of materials, descent and ascent of people and ... Wikipedia

SHURF- (German Schurf), vertical or inclined mine working of small section and depth (up to 25 m). Serves for the search and exploration of minerals, blasting and other ... Modern Encyclopedia

SHURF- (German: Schurf) a vertical or inclined mine working, which has access to the surface, a small section and a depth (usually up to 25 m). Serves for exploration of minerals, blasting, etc ... Big Encyclopedic Dictionary

Books

Echo Chronicles 3. Elusive Khabba Han, Fry Max. In the tavern "Coffee Grounds", which stands on the border between the newborn reality and our dreams, Sir Pit Lonley-Lockley appears. There is only one guest, and there are much more surprises than it could be ...

Parameters and methods of driving pits. By depth, exploration pits are divided into shallow - up to 5 m, medium depth - from 5 to 10 m, deep - more than 10 m. In some cases, the depth of the pits reaches 40 m (cuts are usually made from deep pits). The depth of the pits is determined not only by geological conditions, but also by the stage of exploration - shallow pits pass during prospecting; deep pits are most typical for detailed exploration.
More than half of the pits during exploration work are up to 10 m deep. With an increase in the depth of the passable pits, the process of sinking becomes more complicated, the costs of funds, time and energy for lifting, ventilation, drainage and even fastening increase. In connection with the possible increase in the strength of rocks at great depths, the breaking operation is also complicated. Therefore, when driving deep pits, it is necessary to pay special attention to the issues of improving technology and mechanization of work.
Pit holes pass rectangular or round cross-sectional shape; the choice of the shape of the cross section of the pit is made taking into account the physical and mechanical properties of the rocks, the method of penetration and the design of the lining.
The most common are pits with a rectangular cross-sectional shape; recommended typical sections of rectangular exploration pits are shown in fig. 134. In pits with a cross-sectional area in the penetration of 2 m2 or more, two departments are usually arranged - lifting and stair. The cross-sectional area of the pit in the penetration is chosen mainly depending on the projected working depth; for pits of greater depth, a larger cross-sectional area in the penetration is taken. In general cases, between these values, the following relationship can be traced (within the depth change from 5 to 20 m):

where Sp is the area of the cross section of the pit in the penetration, m2;
Hpr - design depth of the pit, m.
The cross-sectional areas of the pits, from which the cuts pass, are taken somewhat large, providing a sufficiently productive lift.
The round shape of the cross section of the pits is chosen in the following cases: when driving in fairly stable rocks of shallow pits without markings (sometimes called "pipes"); when driving pits in loose loose rocks using frame-lowering lining; when driving pits by drilling.

With a round shape, the cross-sectional area of \u200b\u200bthe pit is used (due to the absence of corners) more fully, and the construction of the support, the main elements of which are made of materials stronger than wood (for example, metal), is compact. Therefore, with a round shape, the cross-sectional dimensions of the pit can be taken smaller than with a rectangular shape.
Round pits often pass with a diameter of 0.7-1.35 m, respectively, with which their cross-sectional area in the penetration is from 0.4 to 1.5 m2.
With a round section, the pit can have not only a cylindrical, but also a “stepped” shape - the working is traversed by ledges of different diameters. The diameter of each successive ledge is less than the diameter of the previous (upper) one. The stepped shape of the pits is necessary for the installation of a special type of lining - "frame-window". The relationship between the cross-sectional area in the penetration of a cylindrical pit Sn and its depth Hpr can be expressed by the following formula:

When driving round stepped pits, the relationship between the average, maximum and minimum cross-sectional area of the working is expressed by the formula

The dependence of Scp on Hpr can approximately be expressed by the formula

Among the methods of driving exploration pits, it seems appropriate to single out the following: with manual breaking of rocks, with thawing and freezing of rocks, with the use of drilling and blasting and the method of drilling. Such a division of pit sinking methods makes it possible to characterize them not only in relation to the means of performing the main production operation (destruction of rocks), but also determines, to a certain extent, the significance and technology of other basic operations of the tunneling cycle. So, for example, the driving of pits with manual breaking, carried out in loose or loose-cohesive rocks, requires special attention to the fastening operation, while ventilation of the workings loses its importance to a certain extent. Sinking is relatively often carried out with a low degree of mechanization.
A very specific method of driving pits with thawing of frozen or freezing of thawed watered rocks, including operations to change the thermal regime of rocks in order to change their mining properties.
The method of driving pits with drilling and blasting, used in rocks of various strengths, is characterized by a multi-operational driving cycle and usually a higher degree of mechanization. And, finally, the drilling method, which is currently gaining popularity when driving exploratory pits in weak rocks, is characterized by complex mechanization of tunneling operations and the peculiarity of working out fixing.
Penetration of pits with manual breaking of rocks. Manual breaking is typical for driving pits in soft and loose rocks; this operation is simple and usually not very time consuming. Breaking is carried out mainly with shovels and sometimes picks; in some cases, the rock is first loosened with picks, crowbars, or even jackhammers. The complexity and laboriousness of other operations of the tunneling cycle depend not only on the properties of the rocks, but to a large extent also on the depth of the pits being passed.
Pit-holes with manual breaking go to various depths, however, the largest volume of tunneling work falls on shallow pits.
When driving pits up to 2.5 m deep, the operations of loading and lifting the rock are excluded from the tunneling cycle - in this case, the rock is thrown out of the working to the surface.
Fastening of small pits, passable in soft rocks, is often not performed; ventilation is carried out by natural diffusion.
When driving pits to great depths, the driving cycle includes the operations of raising the rock and fixing the working, the latter having a particularly significant impact on the technology of driving in loose (loose) rocks.
Drilling pits in soft rocks. The preparatory work includes the clearing of boulders and the vegetation layer of the working platform, the dimensions of which are determined taking into account the placement of stacks of rock produced from the excavation near the mouth of the pit and the convenience of working on the surface. Then the mouth of the pit is marked and the rock is removed along its contour to a depth of 0.5-1 m. A tunneling frame is installed above the mouth of the pit, the dimensions of which in the clear are equal to the transverse dimensions of the pit. The ends of the frame elements should protrude beyond the mouth of the pit by at least 0.5 m.
When driving a pit to a depth of 2 m, a manual wrench is mounted on the tunneling frame. Raising rock from a single-tank pit, a tub of small capacity (up to 0.04 m3); a ladder (usually suspended) is used to lower and raise people. Lifting installations with a mechanical drive are used in rare cases. When compiling geological documentation and testing directly in the pit, the rock brought to the surface is placed in a compact dump near the mouth of the pit.
In cases where samples are taken from the rock issued from the pit, this rock must be poured into separate piles, sometimes called “driving”. The laying out of "driving" as the pit deepens is carried out sequentially around the perimeter of the working platform.
The pit is usually fixed after driving to a depth of 3-4 m. This part of the working is most often fixed with a continuous crown lining. The upper rims of the support protrude 1 m above the mouth of the pit and are equipped with pits (Fig. 135).
At greater depths, with sufficient stability of the rocks in the pit, instead of a solid one, a crown support is installed on racks or, more rarely, suspended. A safety shelf is arranged above the working face. When water enters the pit, it is removed, as a rule, with buckets.
Ventilation of pits, as noted above, is carried out mainly due to diffusion. With a significant depth of the pits, wind pressure is used for ventilation, mounting inclined shields or sockets above the mouth of the pit.
The tunneling link usually consists of three people - a sinker and two turners. With a cross-sectional area of a pit more than 2 m2, two sinkers can work simultaneously in the face. In the practice of geological exploration, the penetration of pits in soft rocks per shift is from 1 to 2 m; the average monthly penetration ranges from 20-40 m.
During the liquidation, the pits fall asleep, the lining in some cases is completely or partially removed, but more often they are left in the development.

Sinking of pits in loose loose rocks. A significant difference in the technology of driving pits in non-cohesive loose rocks that do not allow more or less significant vertical outcrops lies in the features of performing the operation of fixing the excavation and lining structures.
A characteristic feature of sinking operations is the use of frame-descent lining. The method of driving pits with frame-lowering support (Fig. 136) is most widely used in the exploration of gravel and boulder-pebble deposits.
The design of the support allows passing round pits with ledges 2-4 m high; each ledge is fixed in the process of its penetration. Prior to the start of drilling, the pit is set by its depth Hpr, based on which, taking into account the selected parameters of the ledges, the diameter of the upper ledge (the mouth of the pit) is determined by the formula

where dу is the diameter of the lower ledge, usually taken equal to 0.8-1.1 m;
a" - the difference in the diameters of adjacent ledges, determined depending on the design features of the lining (0.2-0.3 m);
ny \u003d Hpr / hu - the number of ledges in the designed pit (hy - the height of the ledge, taken equal to 2-4 m).
Giving the pit a stepped shape leads to a rather significant increase in its volume compared to a cylindrical pit.
In table. 42 shows a comparison of the volumes of cylindrical and stepped pits; the calculations were made at dy=1 m (the diameter of the cylindrical pit is taken equal to dy); hу = 3 m and a" = 0.2 m.
After marking the contour of the mouth of the pit on the working platform, a tunneling frame is installed and a wooden or metal pile driver is mounted, equipped with a crank and a winch for lowering and raising the frames (Fig. 137).

The diameter of the mouth of the pit should exceed the outer diameter of the first support frame by 10-20 cm. The rock separated from the face with shovels is thrown to the surface; the excavation is continued to the maximum depth, which ensures the stability of the walls of the pit. Then, with the help of a winch, a frame is lowered into the pit, along the outer perimeter of which boards (formwork) are installed. Pit penetration to the depth of the first ledge is carried out with simultaneous settling of the frame and formwork. After driving the first ledge, the space between the walls of the pit and the formwork is packed; the frame is attached to the tunneling frame with the help of screeds.
The operations of sinking the second and next ledges of the pit are carried out in the same sequence: the contour of the ledge is outlined, the rock is partially excavated along the height of the ledge, a frame is installed in the recess and a formwork is laid around it, the ledge is deepened, upsetting the frame with a sledgehammer.
The use of a frame-lowering support reduces the labor intensity of fastening and the cost of excavation, and also ensures a higher safety of work.

When driving pits with a frame-lowering support in the North-Western Geological Administration, significant savings in the consumption of materials and an increase in the rate of drilling of pits were achieved compared to driving CO pits under the same conditions with a solid ring support. The average monthly rate of penetration of pits with a frame-lowering strength is 25-35 m.
Sinking of pits with thawing or freezing of rocks. When driving pits in the frozen strata of sedimentary rocks, the breaking operation becomes laborious due to the significant strength of the rocks in the frozen state. Natural or artificial thawing of frozen rocks makes it possible to reduce the labor intensity of blasting, reducing this operation to manual loading of soft rocks into a bucket. Natural thawing of the rock, carried out under the influence of solar radiation, is a long process and can be of practical importance only when driving in the summer a significant number of small pits located in a dense grid. Artificial thawing is carried out by "burning", boot and steam.
Defrosting by fire is used when driving prospecting or exploration pits in forest areas. The pits, as a rule, pass in winter, since in the warm season the workings are flooded with groundwater. The thawing of the rock is achieved by breeding a bonfire (burn) directly at the bottom of the pit. One burn consumes from 0.2 to 0.35 m3 of firewood. The depth of thawing, depending on the quality of the fuel and the properties of the rocks, is from 0.2 to 0.4 m. The average consumption of firewood is 0.4-0.5 m3 per 1 m3 of rocks. When fuel is burned, the walls of the pit also thaw, losing their stability. As a result, an increase in the cross section of the working is inevitable, as well as additional work on cleaning the rock that has fallen out of the walls and fixing the pit. With a significant ice content of the rocks, water accumulates in the bottomhole, as a result of which part of the fuel does not burn. With the deepening of the pit, insufficiently efficient air circulation reduces the intensity of fuel combustion. Rock removal can be carried out after thorough ventilation of the pit, defrosting of thawed walls and fixing of workings.
Rubble thawing is as follows: rounded stones (stone, cross-sectional size 8-10 cm) are heated on the surface in fires laid out near the mouth of the pit to a temperature of 200-300 °C. The total volume of buta, depending on the section of the pit, is from 0.5 to 1 m3. A recess is made in the center of the bottom of the pit, hot stones are thrown or stacked into it and covered with a layer of moss to reduce heat losses. After thawing, which lasts several hours, moss and rubble are removed from the mine and the thawed layer of rock with a thickness of 0.15-0.3 m is loaded into a tub. The consumption of firewood used for heating buta is from 0.2 m3 or more per 1 m3 of rocks. With rubble thawing, there is no need for artificial ventilation of the pit, the walls of the working remain stable and may not be fixed.
Steam thawing is characterized by higher efficiency and can be recommended for a large amount of borehole work, however, it is rarely used in field exploration practice. To organize steam defrosting, the following equipment is required: a steam boiler, a steam pipeline with a switchgear, rubber hoses and hollow drills (Fig. 138). The operation of steam thawing consists in the fact that hollow drills are driven into the bottom of the pit to a depth of 0.15-0.2 m and steam is supplied to them. As the rock thaws, the drills are driven into the face with a hammer to a depth of 0.6 to 1.2 m, and when steam is supplied, the rock is thawed for 2-4 hours.

The thawing of frozen rocks by steam proceeds very intensively, however, the contours of the pit are fuzzy. It is advisable to excavate the rock after 2-3 hours after turning off the steam, since at this time thawing continues due to the heat of the rock heated near the drills. The pit with this method of penetration can not be fixed.
In sediments with a high filtration capacity, water inflow significantly complicates, and sometimes makes it impossible to drill holes at all. One of the ways to simplify mining in these conditions is the freezing of rocks (driving pits is carried out in winter at a negative temperature). When the bottom of the pit approaches water-bearing rocks and, in particular, quicksands, the drilling is stopped for some time, which is necessary for the freezing of the rock layer, after which the drilling is carried out to a depth less than the thickness of the frozen layer, etc.
When driving pits in frozen rocks, interspersed with layers of thawed watered rocks, a combined sinking is used: a pit is passed through frozen rocks with thawing, through thawed rocks - with freezing (Fig. 139), and the excavation of frozen water-bearing rocks is also carried out with thawing (rubble). The use in this case of explosive breaking, which is relatively often used in frozen rocks, is associated with the risk of flooding the working after the explosion and is not recommended.

Freezing and thawing of rocks in the face is carried out at a relatively small depth of the layer removed per cycle. The duration of these operations depends on the climatic conditions and the defrosting method used. Productive work is achieved with the multilateral method in the case when the tunneling team simultaneously passes several pits located at a short distance from one another. An approximate work organization schedule is shown in fig. 140.
Sinking of pits with drilling and blasting. Characteristics of tunneling works. Drilling and blasting is used when conducting pits in rocky and frozen rocks. This rock breaking method is used when driving relatively shallow pits at all stages of field exploration, when pits traversed in soft and loose rocks, individual interlayers of rocks of IV and higher categories of strength, when pits are deepened into bedrock (“finishing” pits). However, this method is most typical for driving pits to a great depth in fairly strong rocks.

Shallow blastholes are still often carried out without mechanization - manual drilling of holes, the use of wind power or hand fans for ventilation, lifting the rock with hand cranks. This is largely due to the small volumes and dispersal of drilling operations, the lack of effective transport links or, in a particular case, electricity.
The sinking of deep pits, as a rule, is a mechanized production process; the degree of mechanization predetermines the deadlines, material and labor costs of drilling operations.
Means of mechanization of tunneling operations. Holes are drilled with light manual pneumatic perforators (supplied with compressed air from mobile compressors installed at the mouth of the pits) or hand-held electric drills. In some cases, motor-operated hammers can be used (provided that the exhaust pipe is connected to the suction fan pipeline and the pit is strengthened to ventilate). The mechanization of the loading of broken rock remains practically unresolved to date. The use of clamshell loaders of the type used in the sinking of mine shafts is difficult due to the small cross sections of the pits. Created by the Special Design Bureau of the Ministry of Geology of Russia, the small-sized grab loader GShK-1 with a grab capacity of 0.01 m3 and designed for pits with a cross-sectional area of more than 2 m3 has not found application due to low productivity. It seems appropriate to recommend the use of rope grabs of a slightly larger capacity not for loading the rock into a bucket, but for removing it from the face and lifting it to the surface. In exploration parties, the AG-1 drilling unit with a hydraulic grab-lifter is being tested.
Bucket lifting of the rock is carried out using small cranes, some of the designs of which have been described previously. After blasting, the workings are ventilated with small centrifugal fans, and drainage is carried out with electric pumps and motor pumps.
In geological exploration parties that carry out mining operations in significant volumes, along with the use of individual machines and mechanisms, complex units are used.
The ShPA-2 unit consists of a diesel engine, a compressor, a drive lifting and manual auxiliary winch, a fan and an electric generator. The set of equipment includes an electric saw and electrical equipment: a frequency converter, a control panel, an alarm system, starting devices, and lighting. All equipment is placed on a car trailer.
Similar drilling units are manufactured in the West Kazakhstan complex expedition (the unit consists of a Pioneer crane, an electric generator, a compressor, a fan, a remote control and an alarm). On the basis of a skidder, the Yakutsk Geological Administration has developed a self-propelled drilling unit equipped with a lifting and turning mechanism with a pneumatic grab and a compressor. The complex of tunneling mechanisms KMSh-VITR consists of an electric portable station with a gasoline engine, a boring crane KSH-100, a pump, a centrifugal fan and a manual electric drill. The complex is convenient for transportation in off-road conditions, it can be easily disassembled into separate units weighing less than 80 kg.
Technology and organization of penetration. The cycle of tunneling operations begins with the drilling of holes. When driving shallow pits with a small cross-sectional area, the holes are drilled (and hollowed out in frozen rocks) by hand. Their depth is usually small (0.2-0.4 m when chiselling holes with crowbars and less than 1 m when drilling with chisel drills).
The small depth of the holes, their increased diameter during chiselling (up to 10-12 cm) and the insignificant cross-sectional area of the mine working (up to 1.25 m2) make it possible to limit oneself to drilling sets of 2-5 holes (Fig. 141).
In pits of large cross-section during perforating or electric rotary drilling of holes, their depth reaches 1.2-1.4 m, and the location and number are taken in accordance with the selected type of cut and the area of the face.

In pits with a cross-sectional area of less than 2 m2, holes are drilled by one person; with a larger area, two drillers can work simultaneously. Charges and explodes the holes of the explosive or sinker, who has the right to conduct blasting. Explosion of holes is electric, it is carried out from the earth's surface with the help of an explosive machine. With a significant number of boreholes, approximately 30 minutes are allotted for the operation of charging and blasting (2-3 minutes are spent on charging one borehole).
With two- and three-shift work, it is advisable to time the ventilation of the pit to coincide with the break between shifts; during one-shift operation, the gaseous products of the explosion are usually removed from the mine due to diffusion or wind pressure during non-working hours of the day.
Before starting to clean up the rock, the face after ventilation is brought to a safe state - they inspect and fix the support damaged during the explosion; rob the loose walls of the pit; pump out, if necessary, the water accumulated during the ventilation.
The breed is loaded manually or by mechanical loaders. With a sufficient cross-sectional area of the pit to lift the rock, it is advisable to use two buckets - while loading the bucket uncoupled from the lifting rope, the other, previously filled with rock, is lifted to the surface, unloaded and lowered into the pit. Rock harvesting takes up most of the tunneling cycle time.
In hard rocks, which are usually characterized by increased stability, the pit is fastened with a significant lag from the bottom, and the fastening process is often not included in the cycle of tunneling operations.
The installation of the lining and the reinforcement of the pit is usually carried out in shifts specially allocated for this, after several tunneling cycles have been completed.
An approximate work organization schedule is shown in fig. 142.
The average monthly penetration of pits reaches 30-40 m.

The tunneling link usually consists of three or four people: one or two work in the mine, two work on the surface. Sometimes the tunneling team works using the multilateral method simultaneously on the sinking of several pits. This ensures better organization of work and reduces downtime associated with blasting and ventilation.
General information about the explosive method of driving pits. The sinking of pits in relatively easily deformable rocks, which is reduced to the formation of a mine working due to irreversible deformations of rocks (clays, loams, sandy loams, loess) during the explosion of a charge, is called explosive driving. In wet clays, this driving method is particularly effective.
The drilling technology is very peculiar and boils down to the following: a well is drilled to the design depth of the pit; the well is backfilled with placer BB; detonators, electric detonators and a detonating cord can be used as initiators. After blasting, the resulting development is subject to thorough ventilation. The need for fastening the pit in many cases disappears, since the rocks, as a result of the explosion, are deformed, compacted and become quite stable.
In pits formed by explosives, with a relatively regular round cross-sectional shape, the diameter of the working along its height does not remain constant, the formation of an ejection funnel in the upper part of the pit is also characteristic. Between the volume of the charge (Azar) and the volume of the cavity (Avyr), formed in the rock after the explosion, there is an almost direct relationship Avyr=kAzar. The value of the coefficient of proportionality k depends on the properties of rocks and explosives.
In the practice of driving pits in clays, loam and loess, when using ammonites, the coefficient k is taken in the range from 150 to 300. For the convenience of calculations, moving from volumes to diameters of workings and charges and taking the value of k in the recommended values, we will have

The data obtained by calculation are approximate, they should be refined during experimental explosions. The blasting method is characterized by low time and material costs, high labor productivity, it is applicable in cases where the pits are used as transport workings, and geological information is obtained when driving cuts from these pits.
The technology of drilling holes in clays and weathered clay tuffs, adopted in Pervomaiskaya and Merkushevskaya GRPs of the Primorsky Geological Administration, is of interest. Shafts up to 15 m deep with a cross-sectional area of 1-1.25 m2 are drilled and blasted, a feature of which is the use of boiler charges. A central hole is drilled in the face, shot through it, and a charge weighing 3-5 kg is placed in the resulting chamber. During the explosion of the boiler charge, the rock is partially pressed into the walls of the working and partially (at a small depth of the pit) is ejected to the surface. Only 25 to 50% of the blasted rock is subject to cleaning from the pit.
Penetration of pits by drilling. Characteristics and conditions for the use of drilling pits. During the last decade, the drilling method of driving pits began to be introduced into the practice of mining exploration.
The drilling method of driving pits is characterized by a number of significant advantages that distinguish it from other methods. The penetration of pits by drilling provides a significant improvement in working conditions and safety of work, the achievement of the highest technical and economic indicators, the exclusion of hard work and the comprehensive mechanization of the construction of exploration workings.
The improvement of working conditions and safety of work is a consequence of the fact that in the process of drilling a pit, the worker is not in the working face, but on the surface; the operation of fastening the pit is less laborious and faster; there are proposals for the mechanization of the selection of bulk samples from the bottom of the pit, in which the need for a person to stay in the development generally disappears.
High technical and economic indicators of pit penetration by drilling include a sharp increase in penetration rate, and a reduction in labor and material costs.
Let us illustrate this with practical data from one of the expeditions of the Ministry of Geology of Russia, which introduced the drilling of small pits on a large scale (Table 43).

At present, only with the drilling method, one can speak of a truly comprehensive mechanization of pit driving. Operations of breaking rock in the face, issuing it from the development and placing it on the surface in dumps are mechanized; the problem of mechanization of the construction of lining in the pit, which has the correct shape of a cylinder, is not unsolvable (there is already a project for the design of a portable support layer mounted on a drill string); in addition, in some cases, the fastening of the pit may not be carried out. The scope of the drilling method is still limited to weak rocks (I-IV categories of drillability).
The institutes TsNIGRI and MGRI (Moscow Geological Prospecting Institute) have developed and are testing the designs of drilling rigs for drilling exploratory pits in medium-hard rocks.
The used transportable drilling rigs provide drilling of pits up to 30 m deep and more.
The drilling method of sinking is especially effective with significant volumes and concentration of drilling operations.
Applied equipment. Pit holes are drilled mainly in a rotary way with units mounted on the basis of a car, tractor or trailer. Some of these rigs are suitable only for drilling pits, others are universal, they can drill pits and shallow exploration wells. As a drilling tool, mainly auger and less often bucket cylindrical drills of various designs are used. Shaft drills are designed to destroy the rock face and periodically lift the destroyed rock to the earth's surface. The rock is destroyed by the cutting edges of the auger flanges or the bottom of the cylindrical drill; the destroyed rock is accumulated on the shelves of the auger or in a cylindrical body and, together with the drill, rises from the working.

Installations for drilling shallow pits are usually cars with simple attachments mounted on them (Fig. 143).
Pit holes of medium depth or deep drill with installations mounted on the chassis of vehicles (Fig. 144), on trailers with independent drives or on trailers in combination with truck cranes. The drilling rig UBSR-25 is mounted on the basis of a skidder. The characteristics of drilling rigs used for drilling pits are given in Table. 44.

Technology of penetration and fastening of pits. After clearing and leveling the horizontal platform on the surface and bringing the drilling rig into working condition, they start drilling pits. The production process of driving a pit consists of lowering the drill to the bottom, drilling (usually to a depth of 200-400 mm), lifting the drill filled with rock, and unloading it on the surface. The duration of tripping operations increases sharply with the increase in the depth of the pit, if it is necessary to build up and dismantle the string of drill rods with each run. In some installations, this drawback is eliminated due to the design of a bucket-type dredger sliding along the drill rods, which is raised and lowered on cables without disassembling and building up the rod string.
At present, sliding auger drills and combined rock drills of the MGRI design have been developed and are being tested, which make it possible to increase the trip deepening by two to three times, as well as to perform tripping operations without disassembling the drill string.
Bucket augers are unloaded either manually or with the help of rotary blades that form the body of the drill and are rotated during unloading by a special hydraulic drive (bucket drill LBU-50 installation). Auger drills are usually unloaded by rotating them at an increased speed (unloading due to developing centrifugal force). When unloading the pit drill, the mouth of the pit is covered with holes.

The fastening of the pits passed by drilling is simplified due to the relatively regular cylindrical shape of the workings, while creating favorable conditions for the use of reusable, prefabricated, sometimes called "inventory" lining. As the main fastening material, wood is losing its importance and is being replaced by metal or plastics.
It is possible to use a round frame lowering support, however, a significant difference in the diameter of the steps of the pit requires the use of a set of pit drills of different diameters. When replacing wooden puffs with fiberglass plates, the difference in the diameters of the steps of the pit decreases and, at the same time, it is possible to use one pit drill equipped with an expander.
The use of spacer split rings made of angle or channel steel with wooden or fiberglass puffs can provide fastening of a cylindrical pit.
With the UBSR-25 rig, the pits are drilled with casing metal pipes, which serve as a reliable support.
In the practice of drilling pits in the Ural complex expedition, the workings are fixed with metal rings, consisting of two half-cylinders, bolted together.
Good results were obtained during production tests of ring support made of polyethylene and vinyl plastic rings with longitudinal cuts, reinforced at the ends with angle steel. The assembly of the rings into a column and its installation in the working was carried out after the completion of the drilling of the pit using a drill string equipped with a support frame at the end. The support made of fiberglass cylinders with a cut along the generatrix has a significant elasticity and. therefore, it can be considered "universal" - allowing the use of standard rings for pits of various diameters (from 600 to 1150 mm). Rings enter one another to a depth of 150 mm; the rigidity of the support is provided by special locks.
When the pit is eliminated, the considered structures provide the extraction of the support for reuse.

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