Every treasure hunter who searches for treasures in old houses knows perfectly well that it is difficult to open the layers of earth using traditional methods.
Also, builders and repairers of foundations understand that in conditions of dense urban development it is quite difficult to make a high-quality repair of the foundation, because it is not known what the depth of the foundation, its type and size, even the thickness is sometimes difficult to calculate. Therefore, when it is necessary to make a survey of foundations, it is recommended to use the technology of pitting.
What is the essence of this technology
When the building has visible signs of damage associated with the destruction of the foundation, then it is necessary to determine the degree of damage to the structure and the possibility of its repair. In such cases, it is strictly forbidden to use well drilling, because the destruction can continue. In such cases, they dig a hole in several places.
A pit is a deep round hole that is dug to the maximum possible depth along the outer or inner surface of the foundation. When a foundation survey is carried out for the purpose of repair or restoration, there may be about a dozen such pits, and sometimes even more.
The pits are located symmetrically with respect to the surface, in most cases they are equipped on the outside of the building, because it is difficult to dig inside.
When to Inspect Foundations and Foundations
- With a planned increase in the number of storeys of the building;
- Changing the purpose of the building, technical re-equipment of the production building;
- Capital or planned repair of the foundation associated with the appearance of visible signs of deformation of the supporting structure;
- With the appearance of significant cracks, deformations and subsidence of the basement floor, as well as the facade of the house;
- In the event of subsidence, not related to seasonal fluctuations in the soil;
- When designing and starting the construction of other buildings nearby;
- If you need to carry out restoration and restoration work in architectural monuments, sculptures with pedestals and other similar structures.
In some cases, to examine the foundations and obtain the finished result, it will be enough to study the technical documentation for the building. But for old buildings, such projects simply cannot be found, because they do not exist, and construction archives were not maintained then.
But, when the building gives systematic subsidence, the situation worsens, and it is also necessary to carry out the restoration of the existing building, then the foundation is inspected in full. And drilling here will be the best method.
Causes of deformation and destruction of building foundations:
- Rainwater that has penetrated deep into the foundation through cracks, pores, or a damaged drainage system;
- Aggressive groundwater contaminated with chemicals that got deep into the base from damaged sewers;
- Ground water raised above the permissible level;
- When mistakes were made in the design of the foundation, poor-quality building materials and products were used that were not designed for design loads;
- Natural aging of building materials, in particular sandstone, limestone and rubble;
- Through the occurrence of third-party vibration from new industrial and administrative buildings, which affects the foundation from the outside;
- Displacement of soil layers, other reasons.
The pitting method makes it possible to clearly establish the composition of the base, its depth and the composition of the mineral components. When pitting, soil and foundation samples are taken at various depths, a visual inspection of the structure is carried out, and samples of building compositions are taken. Often it is necessary to completely open the foundation in order to examine the condition of the reinforcing layers.
How to properly arrange pits
Considering that a pit is a hole dug vertically or at a slight angle, which completely opens the surface of the foundation, then you need to dig it correctly.
Places for installing recesses are selected individually in each specific case, places with clearly localized damage to the base are considered priority. Also, the pits can look like a long trench, if you need to examine adjacent sections of the tape base.
When choosing a digging site, you do not need to start only from the convenience of work. Inspection of foundations should be carried out in full, regardless of the complexity of the work being carried out, because the reconstruction and repair of foundations is always carried out in densely populated areas with dense buildings.
Therefore, before starting work, you need to warn others, and all such work is temporary and after a few days the pits are again covered with soil.
Examination of bases and foundations is of a forced and critical nature in places of clearly visible critical damage. Also drilling is carried out:
Areas where building damage is considered critical also require special attention. In such cases, pits are installed not only in the emergency zone, but also in neighboring areas in order to detect reliable zones and balance the building by load transfer.
As a rule, during the reconstruction of a house, a foundation survey is done along the entire perimeter of the building, but with a possible superstructure, only in a specific area.
How many holes need to be made?
- The amount depends on the degree of damage to the foundation. If it is a strip or monolithic foundation, then the pits are made every 1 meter or even closer. Also, 2-3 control samplings are always performed in independent places, in order to then make a comparative analysis of the composition of the foundation and the soil around it.
- If you only need to conduct an examination, then make 2-3 pits for every 10 meters of base length.
- When eliminating the entry of groundwater, pits are dug already in advance dried areas of the basement or basement. And if the basement is deepened, then one hole in the middle of each wall is enough.
- In cases of detecting fluctuations in the level of the base or a significant drawdown, the pits are installed double-sided in order to find the cause of the drawdown.
All pits are always dug to a depth below the sole of the base for at least another half a meter.
The results of drilling can be as follows:
- there is data on the depth of the underground part;
- the overall dimensions of the base are obtained;
- the laboratory received information about the state of the foundation and the degree of its strength;
- the presence of defects and destruction;
- class of concrete, brand of stone;
- there is data on the state of waterproofing;
- base geometry can be checked;
- also, an increase in loads on a specific section of the foundation will always be detected.
How to open foundations by drilling
Given that one of the walls of the pit, which is used to examine the foundations, will be the outer surface of the foundation, then there are three main options for opening them:
- double-sided - then the pit is dug out on both sides symmetrically and connected from below the sole. It is used if there are significant deformation subsidences or if there is a possibility of the influence of excess loads from superstructures.
- corner - a hole is also dug on both sides, but it does not connect and has a slight slope. The depth in such cases may not be to the very bottom of the sole. It is satisfied with the same dimensions of the reinforced concrete base and the absence of the influence of sedimentary processes. When examining the foundations of industrial facilities, the uniformity of loads from the installed equipment and the lack of the possibility of dismantling are also taken into account.
- perimetric - complete exposure of all surfaces of the foundation on three sides, and the fourth may not be exposed. This method is used in critical situations where a complete inspection of the base or ground is required. But the opening of the foundation, in this case, is allowed to be carried out not immediately around the entire perimeter, but only in sections that are no more than one and a half meters long, otherwise the building under investigation may collapse.
Sometimes a situation arises when more pits are used for a small private house than when examining a huge industrial enterprise.
The reason for this lies in the following: the specific conditions for the analysis and sampling, as well as preliminary measurements, largely affect the survey.
As a rule, all this is done by professionals, so the human factor is minimized. It happens that during the initial sampling there are already significant discrepancies between the design and the technical documentation. Therefore, additional drilling is required.
If you are looking for coins with a metal detector, then sooner or later you will hear the word "shovel".
What is it - to drill, and when is it necessary?
Digging in the application to the search for coins with a metal detector means local removal of soil and checking each layer.The width of the pit can be different, from the width of a shovel to several meters. Length is the same. As a rule, the minimum pit is 1m by 1m. But most often 3m by 3m.
The depth of the pit from the spade bayonet (30cm) to 70cm (or 1m).
Usually they drill to dense soil. Those. they pass through the cultural layer, reach the clay, and then they can stop.
When does the need arise?
The need for shurfeniya arises in several cases. But all of them are united by one thing - there is no way to find valuable finds at this place. This may be due to the presence of metal debris, or due to a lack of search depth (with a metal detector).Those. working as a metal detector, you constantly get a lot of black signals, or you have already found coins on top, but then you do not have enough depth.
What do you do then? ... You start to remove the soil in layers and check it for interesting targets. Usually one layer is the half of the bayonet or the spade bayonet.
Also, check the bottom of the hole.
When the need arises to poke
The need to dig when searching for coins can arise for various reasons. Here are a few of them:- You are interested in this place. You just feel that there is something there. You have an irresistible desire to remove the top of the soil
- You have found some coins. There is a suspicion of a plowed treasure
- You found stuck coins. This happens if there is a stolen treasure deeper
- You see a failure (former cellar). There is an idea to open it and check the walls, the floor of the cellar.
- You see the old foundation of the house. There is a possibility that there will be finds around it.
How to grind properly?
Before starting shurfeniya need to localize the place. Those. to outline the most likely location of the coins (plowed treasure).
Next, you need to clean it up. Remove everything that interferes: large debris, bushes, tall grass, etc.
You need to determine where you will put the first layer of soil. Usually this place is located near where you are going to dig. Those. You think that there will be no finds in this place and therefore you will put soil there.
Further options are possible depending on the depth of the pit.
- If the depth of the pit is near the bayonet of the shovel, then you put each subsequent row on the previous one (the place has already been dug and checked). Then at the end of the drilling you will not have any pit, everything will be filled up.
- If the hole is deep. Then you simply lay out the soil next to it (checking it), and at the end you simply fill in the hole formed as a result of the drilling.
Why is it worth poking around?
Often, deeper layers of soil simply do not penetrate the metal detector. Due to the fact that there is a lot of metal debris, due to the fact that the soil itself is highly mineralized.The top of the treasure may appear on the surface, and its core will be much lower.
In addition, the finds may simply be covered with iron debris.
Well, if you are digging a basement, then the metal detector, in principle, cannot penetrate to such a depth.
Which metal detector to choose for scanning
Any metal detector is suitable for scanning, from beginner to professional level. The depth of the search is not important here. Even too big will only get in the way. (Because you are checking the excavated soil, the layer thickness of which is small)But a large coil (large diameter) is simply contraindicated.
The coil should be small or medium in size.
GENERAL REQUIREMENTS
Prior to the reconstruction of pipelines, measures are taken to prepare construction production in a volume that ensures the implementation of all work as soon as possible, including general organizational and technical preparation, preparation of engineering networks for reconstruction and equipment for installation work.
Reconstruction of each object is allowed only on the basis of an approved project and decisions on the organization of construction and work technology. All stages of the work should be carried out under the control of the organization that is entrusted with the author's and technical supervision of the reconstruction work, and organizations operating adjacent communications.
Prior to the start of earthworks, access roads must be provided (installation of additional road signs, etc.), as well as fire and explosion safety measures must be taken throughout the entire period of work.
The organization performing construction and installation work, including excavation, must have a plan of engineering networks indicating the sections that cannot be restored and the places where these sections are connected to the pipeline under reconstruction, as well as drawings for torn pits or trenches indicating the exact dimensions and passing nearby with them underground engineering structures and communications with their binding to permanent landmarks.
Prior to the commencement of work, the installation organization must obtain a permit, which is issued by the local administration.
The route of the reconstructed pipeline is determined by the operating organization with notification of organizations operating neighboring underground utilities. On the route in kind, the contours of the trench planned for opening are marked.
Prior to the opening of road surfaces and the development of pits, trenches and pits, the following measures must be taken: to protect the entire perimeter of the work site with inventory boards or a metal mesh indicating the organization conducting the work and the telephone numbers of the responsible work supervisor; when performing work on the roadway, put up warning signs illuminated at night, at a distance of 5 m from the direction of traffic; with the onset of darkness, install a signal red light on the front side of the fence at a height of 1.5 m, and illuminate the work site with spotlights or portable lamps.
The width of the fence sections is assigned depending on local conditions. The length of the fences is established by the project for the production of works. The opening of road surfaces and the development of trenches should be carried out in accordance with the project for the production of works.
If there are electric cables, communication cables and other underground utilities in the places of digging a pit or trench, excavation is carried out with prior notification and in the presence of representatives of the organizations operating them, in compliance with measures that exclude the possibility of damage. Cables within the limits of transfer after opening the trench should be enclosed in protective cases made of plastic or wooden trays, boxes or pipes, suspended, if necessary, from the beam.
If any underground utilities or structures not specified in the project documentation are found, work should be stopped, the author of the project and representatives of organizations operating adjacent communications should be called to the place of work to determine the ownership of these structures and take measures to preserve or eliminate them and make changes to executive documentation.
Before turning off the coolant, water or gas in the reconstructed pipeline, consumers supplied from the disconnected section of the network are provided with the help of a bypass.
PREPARATORY AND AUXILIARY WORKS
The preparatory and auxiliary works associated with the development of pits and trenches include: laying out the routes of existing pipelines, ensuring their stability, drainage and lowering the groundwater level, opening road surfaces (if necessary).
For the reconstruction of pipelines associated with the digging of trenches and pits in cities and towns, permission is issued by the administrative inspection. Such a permit is called a warrant, and it is received by a specialist in a construction and installation organization, a work foreman or a site manager who has the right to carry out work, who sign the warrant and bear full responsibility for the construction on the allotted site. The responsible specialist, in whose name the warrant is issued, must comply with the "Rules for the production of work on the laying and reconstruction of underground structures" in his work.
Prior to the start of excavation work, the head of the construction and installation organization is obliged, no later than a day before the start of work, to call representatives of the organizations specified in the order to the route, establish together with them the exact location of underground structures and conduct an appropriate briefing with workers involved in construction before the start of work. At the intersection of reconstructed engineering networks with existing underground utilities, the places where these structures are at risk of collapse are marked with appropriate signs. If soil development is envisaged in the immediate vicinity of the foundations of existing buildings, structures and communications, it is necessary to provide measures against the settlement of these structures.
To determine the location and opening of an underground structure, a pit-opening is made with a width of 0.7 m, a length of 1-2 m and a depth indicated in the notification scheme. The search is carried out in the presence of the person responsible for the construction and a representative of the operating organization.
Underground communications should be opened up to the design marks of the pipeline. The pit is fixed with standard shields, and the discovered underground utilities and cables are enclosed in wooden boxes made of boards 3-5 cm thick and, using wire twists, are suspended from a wooden or metal bed laid across the trench. The ends of the bed lead beyond the edges of the trench by at least 50 cm. If there are existing underground utilities or other structures that are not indicated in the project, excavation work is stopped until their ownership is clarified. Suspension of communications and equipment is shown in Fig.1.
Fig.1. Suspension of communications crossing the trench:
A - one or more cables; b - cable duct; in - pipelines; 1 - laid pipeline; 2 - a box of boards or shields; 3 - twisted pendants; 4 - log or timber; 5 - cable; B * - asbestos-cement pipes of cable ducts; 7 - linings; 8 - crossbars; 9 - I-beam; 10 - round steel suspension; 11 - pipeline crossing the trench
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* The numbering corresponds to the original. - Database manufacturer's note.
Note. The dimensions of the sections are enlarged for ease of reading.
Control drilling ensures the safety of existing communications and allows maximum use of machinery and equipment near underground utilities. Communications are opened with the help of shovels, without the use of percussion instruments and only under the supervision of the operating organization. Opening sites are fenced off with signs indicating the purpose of the opened communications, and illuminated at night. In winter conditions, measures are taken to protect opened communications from freezing.
Before the start of the main earthworks, the fertile soil layer must be removed in accordance with the PPR and laid in dumps in order to use it later for the reclamation of disturbed lands, as well as for the improvement of sites. The fertile soil layer should be removed, as a rule, in a thawed state. The removal of the fertile soil layer in winter conditions is allowed only if there is a basis in the POS and agreed with the land user. When removing, storing and storing the fertile soil layer, measures must be taken to prevent its deterioration, mixing with underlying rocks, contamination by liquids or materials.
Reclamation of land plots must be carried out during construction work or not later than within a year after the completion of construction work, during the period when the soil is in an unfrozen state. All types of excavations before the start of the main excavation work must be protected from surface water runoff using permanent or temporary devices.
DRAINAGE, DRAINAGE AND LOWERING OF THE GROUNDWATER LEVEL
For temporary drainage, specially constructed protective enveloping and ditches should be used. All drainage devices, as well as ducts and gutters, during the construction period, must be kept by the construction organization in good and clean condition in order to avoid water entering the trench.
SHURF - a shallow well constructed near the rotor and designed to lower the kelly during the build-up of drill pipes during periods when they are not drilling.
They drill under the hole with a turbodrill or a rotor. To drill a subpit with a turbodrill, a bit, a turbodrill and a kelly are preliminarily assembled above the wellhead.
On the line connecting the center of the well with the right support of the tower (from the side of the bridges) at a distance of 1.5 ... 2.0 m from the axis of the well, a hole for the pit pipe is cut down. A roller and a hemp rope with a diameter of 28.5 mm and a length of 12 ... 15 m are temporarily tied to the same tower support at a level of 1.5 ... 2.0 m from the floor of the drilling rig. Drilling under the pit is carried out in the following order. A turbodrill with a chisel is dragged into the hole cut through the sub-pit. The body of the turbodrill is wrapped around at least three turns of hemp rope. In this case, the running end of the rope (in the direction of rotation of the turbodrill body) must be tied to the tower support, and the running end of the rope is thrown over the pulley and connected to the counterweight. The movement of a turbodrill with a kelly in a vertical position is ensured by bypassing the turns of the hemp rope while maintaining the appropriate tension.
For safe drilling of a pit using turbodrills or an electric drill, a number of enterprises use a special device made in the form of two forged plates bent in the shape of a leading pipe. The plates are put on the leading pipe and fastened together with four bolts. A steel rope is threaded into the existing special holes on both sides of the plates, wrapped around the swivel counterclockwise and fastened in the mouth of the hook. The hook is fixed with a stopper. When drilling under the hole, the leading pipe is kept from rotation by the suspended part of the traveling system, the inertia of which is sufficient to dampen the reactive moment.
The pit is drilled with a depth of 15 ... 16 m. Then two screwed casing pipes (two-pipe) with a diameter of 273 mm are put into the pit, the upper end of the two-pipe is equipped with a visor to facilitate the installation of the end of the leading pipe into the pit. When drilling under the hole with a rotor, its drive can be carried out either through a winch or through an individual drive. When drilling under a hole with a drive through a winch, the rotor is dragged to the place of the hole and set obliquely, for which a board 90 mm thick is placed under the rotor slide from the side of the walkways. The rotation of the rotor is transmitted by means of a chain put on a low-speed sprocket of the winch drum. When drilling under the hole with the help of an individual drive, the rotor is installed and strengthened at the place of drilling the hole at a distance of 1.5 ... 2.0 m from the wellhead.
The machine method of conducting pits in rocks with f=0.1÷4 is characterized by the fact that all technological operations are carried out without the descent of people into the working face.The destruction of the rock and its rise to the surface is carried out by rotary drills or pressure grabs. The drilling of such workings is more profitable to use in areas accessible to vehicles on wheels or caterpillars, as well as in areas with the simplest access roads.
The experience of drilling pits shows that their optimal diameter varies from 0.7 to 1.5 m, and the depth - from 5 to 20 m.
Three types of installations can be used for driving pits: 1) specialized; 2) combined, also providing the possibility of drilling wells; 3) downhole, allowing after a small alteration to pass the pits.
The choice of the type of drilling rig is made only after calculating the power expended on drilling the pit. To do this, you need to select a drill. Before proceeding directly to the choice of the design of the pit drill, it is necessary to resolve the issue of how to lift the drill with destroyed rock from the pit.
With machine driving, cyclic operation is possible, when the destroyed rock rises to the surface at the end of each run, it is possible to completely coincide in time the destruction and rock lifting operations (during auger drilling of pits with a diameter of 0.7-1.0 m), there may be intermediate options, when, for example, rock destroyed over several trips accumulates in a bottom-hole accumulator and then rises to the surface (drilling pits with a diameter of 0.7-1.5 m in loose and flooded rocks).
With a depth of pits up to 4-5 m, it is most rational to use borers, the descent and ascent of which is carried out using a leading rod. With a pit depth of 5-15 m, it is advisable to use sliding pit drills, and at greater depths, accumulating ones.
After choosing the method of tripping operations, you can proceed to the choice of a specific design of the drill.
