How to puncture pipes: technical rules and expert advice
If underground utilities cross a road or railway, dismantling such facilities can be extremely difficult, and often completely impossible. To solve the problem, laying pipes with the puncture method will help. This method is much simpler and cheaper to implement.
If you want to know how pipes are laid in the ground without disturbing ground coverings, demolition of buildings, moving mobile objects, we will reveal the specifics of the technology. Here you will find out what equipment is used in the course of work, how punctures are carried out.
In addition to the title methodology, we described alternative options for laying pipes in the ground using trenchless technology, attached schemes, photo selections, and video materials.
The content of the article:
What is a puncture method?
A puncture method is a technology in which you can get a hole without excavation and excavation by compaction.
This method is suitable for laying steel structures. The diameter can vary between 100-500 mm, the length of the hole is 30-50 m. A puncture under the road is one of the most popular methods for trenchless laying of communications.
Thus, they arrange underground branches of the water supply system, sewage system, lead to the site trunk gas.
Guided puncture is used for laying:
- communications from metal and plastic;
- cases, which are then placed in gas and water pipes;
- cases for power, telephone cables, etc.
A puncture is used not only in cases when it is necessary to painlessly cross a track or railway tracks.
The method is suitable for laying holes in a well (provided that the diameter of this well is not less than one and a half meters), the basement of the house, if necessary, conduct wires under some relatively small object, etc.
Most often, a controlled puncture is performed in the thickness of clay soil under various roads, for example, under a highway or railroad track. To do this, use a pump and jack pressure unit, for example, such as installation Ditch witch p80.
In addition, you will need a set of expanders, rods, heads and other tools with which to perform drilling operations.
Be sure to use a hydraulic station. The required force is provided by the hydraulic cylinder; the acceptable unit power is about 36 tons. The work of the station should be provided by an internal combustion engine. To monitor the progress of work in the thickness of the soil, wireless location tools are used.
As an example, we can consider the operating procedure of the location device Eclipse. A probe is placed in the drill head, which transmits information about the progress of drilling operations.
Information is sent to the locator. Here, the data is analyzed, as a result of which the exact location of the drilling tool in the thickness of the soil, the angle of inclination of the drill head, the correspondence of its movement to the previously drawn up work plan are determined. At the same time, the state of the probe’s battery is monitored.
The drill head is designed so that part of its surface is beveled. This improves productivity, but affects the quality of work.
Due to the bevel, when moving through the soil, the head position will constantly deviate from the impact vector. The operator must constantly adjust the trajectory of the head, referring to the location results.
So that the tool moves strictly in a straight line, it must be rotated at a constant speed. The first stage of the puncture is started in the starting pit, and completed in the reception. Here, instead of the drill head, a conical expander is fixed to the installation.
This device passes the formed horizontal well in the opposite direction, which allows you to expand it and seal the walls.
After that, a pipe of the required diameter or a case for laying communications is inserted into the resulting long hole. Depending on the situation, it is possible to lay not one but several pipes. Further actions are to lay and connect these communications to the common system.
During the preparatory work, it is also necessary to consider the storage location of the pipes, which should be located next to the drilling site.
Typically, a pipe site is provided next to the starting pit. The dimensions of the storage area depend on the length of the pipes, which can reach six meters. Preferably selected for laying pipes stored horizontally. This will simplify installation and reduce the likelihood of structural damage.
In addition, it is necessary to provide access roads to the starting pit in order to seamlessly deliver the materials and equipment necessary for the work.
First, a preliminary survey of the place of work on the ground is performed. In this case, specialists use project documentation, based on which, as well as on the results of the analysis of the object, a puncture execution plan is drawn up.
If it is necessary to perform a puncture under an object experiencing serious traffic loads (tram tracks, highways, railways, subways, etc.), pipes are laid in special cases.
Such a case should have a diameter exceeding the dimensions of the pipes by about 15-20 cm. First, put the case, then mount the pipes in it, and fill the space between these communications with a solution for which you can use an inexpensive cement M-100. Cases reduce the burden on underground utilities and reduce the risk of damage to them.
Hydro, vibro puncture and punching
Distinguish between hydro and vibration punctures. In the first case, a water jet is used as a tool for pushing the soil, which beats from a special tip under high pressure.
This method is especially effective on incoherent sandy soils that are easily eroded by the spray. It allows you to make a hole with a diameter of about 50 cm in a minimum amount of time. But the maximum length of a well with a hydraulic puncture is 30 m.
Vibro-puncture, as the name implies, is carried out using vibration exposure. The device for performing a puncture uses shock-vibration-indentation units with pathogens of longitudinally directed vibrations.
Static indentation is combined with the impact of vibratory hammer pulses on the ground. The method is used on water-saturated and low-moisture sandy soils both for pipe laying and for their extraction. The diameter of the well can reach 50 cm, and its length is 60 m.
The method of punching is carried out using jacks, like a puncture. But in this case, the pipe goes to the ground with its open end. In the process of promoting the structure in the pipe, a dense plug is formed from the soil, which is then removed.
To perform this type of work, two to eight powerful (200-400 tons) hydraulic jacks are used, the operation of which requires the installation of a thrust wall with a frame and a headgear.
Such a device can cover up to 10 meters of soil per shift, and the total length of the well usually does not exceed 80 meters.If you want to lay a longer track, it is divided into separate sections of not more than 80 meters.
This method also requires the installation of a start and finish pit, in which the necessary hydraulics are installed.
Driving each section is performed twice: in the forward, and then in the opposite direction. Control over the operation of mechanisms and the quality of punching is carried out by the operator, who is located in the pit.
Technically, this method is more complicated than a regular puncture, but it can be used on virtually any soil. The diameter of the structure can reach 172 cm. The core sample formed inside the pipe can be selected manually or by mechanized means.
Benefits of the puncture method
The demand for the puncture method is explained by its significant advantages compared to other options for performing work of this type. For example, a puncture is available at any time of the year, high or low temperature of the outdoor air and soil does not matter much.
The operation of the installation does not require the use of a bentonite solution, the supply of water or drilling mud to the well. It is a compact and powerful unit that is equipped with a reliable electrical safety system. It is not difficult to deliver to the object and install it. At the same time, the compact dimensions do not prevent the device from working with high power indicators.
The terms of work are also shorter than with other methods. Even if at the site where the puncture is performed, there is an increased level of groundwater, there is no need to carry out activities to divert water from the site.
During the passage of the expansion cone, the walls of the trench are also compacted, so additional work in this regard is not required.
Performing a puncture at different sites
The complexity and speed of this type of work largely depends on the conditions, i.e. from the terrain and the characteristics of the object under which the puncture is performed. Drilling under the railroad usually requires a fairly serious design. First you need to coordinate drilling with a range of rail services.
In Russia, you need to contact the subdivisions of EC, SC, RCS NODG, PC and other services of Russian Railways. Mandatory contracts for technical supervision, as well as for the installation of safety packages. All executive documentation must be agreed upon and made available to the railway authorities.
A package of documents is transmitted to the distance of the path at the end of the pipe laying cycle. In cities, a puncture under the road is very in demand when laying new communications, especially in places with historical sights.
The method allows not only to maintain the usual traffic on the roads, but also to prevent the destruction of the ancient pavement when it is necessary to lay pipes under such sections.
Restoration of such an object can be difficult, and sometimes impossible. In the cottage villages, laying of communications using the puncture method allows you to perform all work with minimal damage to finished objects: roads, hedges, etc.
In addition to the controlled puncture method, there are other options communication devices in the soil without trenches. Sometimes an alternative may be more acceptable than a puncture, it all depends on the specific situation.
Horizontal directional drilling, which is also called directional, is used for laying pressure and pressureless pipelines.Drilling in this way is carried out from the surface of the earth. The diameter of the hole should be taken 30-50% larger than the dimensions of the pipes that are supposed to be laid in it.
The hole is not expanded immediately, but in several stages. In this case, a bentonite solution is used, which is mixed with loosened soil and facilitates its removal from the trunk. In addition, this working fluid is used to cool the drilling tool, and later on it forms a layer on the walls of the shaft that protects them from destruction.
To pump out the spent bentonite solution, an ilosos is used. After pumping out, the unnecessary solution must be taken to a landfill for further disposal. If the work is done correctly, the result is a clean well with strong walls.
Drilling rigs for performing this type of work have various characteristics, such as torque and traction. The length of the pipes that will be laid in the thickness of the soil, which can reach 1000 meters, depends on this.
The permissible pipe diameter is 120 cm. Both horizontal and metal pipes can be laid by horizontal directional drilling.
Drilling is carried out along a pre-calculated trajectory, the movement of the drilling tool is controlled using a location system. The angle of drilling can vary between 26-34 degrees.
Another important indicator when using HDD is the bending of the rods, which can be 6-12%, it depends on their type. Another popular trenchless pipe technique is screw drilling. For its implementation, a special hydraulic installation is used, acting as a jack.
First, start and finish pits are made. The depth of each of them should be one meter deeper than the level of the pipeline. A hydraulic unit is lowered into the starting pit, which rotates the auger and burst pipes. As a result, part of the soil is removed and a well for the pipe is obtained.
Then, pipes, cases, etc. are installed inside. The maximum laying length is usually only 100 meters, but the diameter of the communications can reach 172 cm, the performance largely depends on the type of soil on which drilling is carried out.
A laser is used to control the work during auger drilling, which provides the correct angle of inclination of the drill, and also allows you to track the direction of drilling with high accuracy. After the auger reaches the finish pit, it is removed from the resulting well in the reverse order.
Microtunneling - This is a high-precision method of trenchless laying of communications, which is performed using a special tunneling shield.
A high power jack station is used to move the device. It affects the column of reinforced concrete pipes that are attached to the shield. Gradually, the length of the well increases, so the length of the column is increased by building reinforced concrete structures.
This method also requires preliminary preparation of two pits; the distance between them can vary between 50-500 meters. The jack installation must be lowered into the starting pit to a depth that corresponds to the level of communications. If the wellbore exceeds 200 meters, an intermediate jacking station is usually used.
A tunneling shield loosens the soil, which is washed with water or bentonite solution, which enters through the supply lines. The waste fluid mixed with particles of soil moves into the sump along the discharge lines.After the tunneling shield falls into the finishing pit, the work can be considered finished.
The equipment is disassembled and removed. Using microtunneling, it is possible to install not only reinforced concrete, but also steel pipes. To control the correctness of the work, a navigation system consisting of a laser, a target and a measuring wheel is used.
For long sections (more than 200 m), an electronic laser system is considered effective, equipped with a hydrostatic level, which gives accurate information about the depth of pipe laying regardless of the air temperature inside the structure.
Subtleties of choosing the appropriate method
The method of laying communications using horizontal drilling is chosen at the design stage of a specific process. If trenchless pipe laying will be carried out as part of the construction of an object, for example, a residential building, then work can become part of the overall construction project.
When designing, the following information is taken into account:
- the length of the communications that must be laid in a trenchless manner;
- case or pipe diameter;
- material of which communications are made;
- depth to which pipes must be laid;
- type of pipeline (pressure or non-pressure);
- the ability to install start and finish pits of suitable depth;
- access roads to the place of work;
- the presence of a sufficiently spacious area for storing materials, equipment, etc .;
- groundwater flow rate;
- other geological features of the site;
- location plan of existing communications on the site.
During the construction process, it is sometimes necessary to change an already completed project. This may be caused by the desire to reduce costs, using, for example, plastic pipes instead of steel. In addition, the layout of underground utilities at the facility is not always accurate enough.
When performing work, such unaccounted pipes or cables may be detected. All these points may require changes in the design, and this may affect the decision on the method of drilling.
If the depth of the laying of communications is small, there is a danger of subsidence of the upper soil layer, especially if a bentonite solution was used during drilling. In such cases, it is better to give preference to horizontal auger drilling.
Very often, the drilling method is determined by what kind of equipment is available to the organization performing the order.
For example, if builders have jacks or an installation for horizontal directional drilling, then he will be preferred over the puncture method. Most often, such changes are dictated by considerations of economic benefit.
Conclusions and useful video on the topic
The process of the installation to perform a controlled puncture is presented in the video:
Guided puncture is a highly accurate and relatively inexpensive way to lay communications under a road or other facility. At the same time, it is important to properly design all the work and strictly adhere to the technology.
Do you want to report interesting facts related to pipe laying using puncture technology? Do you have questions in the process of reviewing the information provided? Please write comments in the block under the text of the article.