sheet piling pit is a temporary fence, which consists of hammered into the ground (along the perimeter of the pit) wooden or steel sheet piles.
They are used for any type of structures with foundation devices in cases where it is impossible to develop the pits themselves in slopes. Pit fencing helps protect structures (and people's lives) from soil collapse.
Note! In order to save money, many construction organizations make sheet piling from pipes.
As for the sheet pile profile, it is made of special carbon steel grades St3ps and St3sp according to GOST 380. When buying, pay attention to the surface of the profile - there should be no sunsets, rolling captivity and rolled bubbles in the places of the end and lock parts.
The installation technology of such a fence involves immersing its elements in pre-drilled wells and pre-filled cement-sand mortar. It turns out that a solution is poured into the drilled wells, up to a certain level (under pressure), and only after that pipes or beams are mounted in the hole.
This technology allows you to protect the structures under construction from soil shedding, as well as significantly increase the bearing capacity of the sheet pile.
Dowel installation options
In addition to the standard method of pouring pipes or beams, there are several more types of installation that are adapted to various conditions and soil types:
- Vibroimmersion- using this method, preliminary drilling of wells for sheet piles is carried out, and then the piles are installed using vibratory pile drivers. On soft ground, it is better to use auger drills. According to estimates, the price for this method of installing fences is the lowest, due to the cost-effectiveness of the technology and the minimum use of technical means;
- Twisting – this way implies the immersion of the sheet pile into the ground (special tips are installed on the piles) by pressing and rotating. This method is in demand in the presence of ready-made, nearby structures. Thus, it is possible to prevent drilling out of the soil from the foundation;
Twisting the tongue
- impact method- carried out by driving piles into the ground using a pile driver. There are a number of limitations in using this method in dense urban areas.
During the development process, the walls of the pit, as a rule, are reinforced with a fence made of edged board or sheet metal. In order not to waste the material, after the arrangement of the building envelope, the pick-up can be used as a formwork element for concreting underground structures and structures.
The sheet piling of the pit with a pick-up is not waterproof, therefore, if the groundwater is located above the level of the bottom of the pit, you should take care of the dewatering system.
By providing such a fence, you can organize a safe area on construction site, thereby significantly speeding up the process of erecting a building or structure.
Also, I would like to note the fact that the use of sheet piles is not limited to the strengthening of pits alone.
They are widely used to strengthen coastlines and trenches, are often used in the construction of flyovers, bridges and overpasses, are used for the construction of hydroelectric power stations and structures of similar directions (locks, waterworks, moorings, bolters).
In addition, sheet piles are used in the construction of warehouses for the storage of liquid and solid industrial waste.
In general, excavation sheet piling looks like a solid wall formed from steel piles (Larsen sheet piles, I-beams, Z profile, pipe and flat sheet piles) by driving them into the ground using one of the above methods.
At its core, such a fence is waterproof and serves as a waterproof partition. But still, the main function of the fence is to prevent the collapse of the soil.
Installation of sheet piling of various types
As mentioned earlier, sheet piles are metal piles installed according to the project along the edge of the excavation (usually used material is usually used for their construction). The most commonly used pipe diameters are 219, 273, 325, 377, 426, 530 and 630 mm.
The pit is fenced according to SNiP in one of the three above ways: by twisting, driving or vibrating piles (see also the article). In any of the above cases, it is required to pre-drill literal wells.
If we talk about prices, then on the territory of Moscow and the region, the most affordable and cheapest option is roller and auger drilling with further strengthening of the well walls with high-pressure mud.
Note! Using these methods, you can order wells up to 25 m deep! The clay that precipitates greatly contributes to the strengthening of the walls and guarantees the tight fit of the pipe.
A little explanation:
- Price fluctuations depend solely on the depth of drilling, the categoricity of the soil and the working conditions;
- When ordering installation work for the installation of sheet piling, pay attention to the fact that the price is indicated only for the work, excluding the cost of the pipes themselves. First of all, this is due to the fact that the contractor does not know which pipes you want to install as sheet piles, and what their wall thickness is.
Bored piles
Bored piles are drilled wells into which different kinds metal frames. After installation, they are filled in: TsPS ( cement-sand mixture), concrete or cement-water base under high pressure.
Advice! Bored piles can be joined with each other using brown-tangential and brown-secant piles, which, together with simple piles, form a monolithic heavy-duty structure.
As for the pricing policy for bored piles, there is no clear answer. The contractor will be able to give you a price only after his personal presence at the site, after assessing the complexity of the work and the type of soil.
Note! In addition to the injection of concrete, CSP and cement-water base, special injections can be introduced into the base of bored piles, with the help of which it is possible to significantly strengthen and strengthen the structure.
Sheet piles in inclined drilling
If you decide to build a house on a hill (hill, mountain, slope), then you can not do without this construction operation. This type of work is carried out using a special drilling rig capable of drilling wells at an angle. The calculation of the sheet piling of the excavation is carried out by specialists on site (it is not recommended to do it yourself, since a small mistake can lead to fatal consequences).
Sheet pile installation
So, above we examined the methods of installing sheet piles, their types and some features when working with them. But what are they? How do they look?
If you look into the good old Soviet encyclopedia, in the section "sheet piling of the pit", you will come across two meanings of the word sheet pile:
- Sheet pile - sheet pile, which received in construction practice shorter and more concise title. It is used in the construction of pits, trenches and hydraulic structures;
- Tongue - a longitudinal protrusion that enters a groove corresponding to it in shape. Serves for connection of elements of wooden designs (shields, bars, boards and so forth).
Knowledge of the device and an example of calculating the sheet piling of a pit are perhaps the most important elements in this case. In general, sheet pilings are temporary structures that are formed from driven (in pre-drilled wells) piles.
sheet piling calculation
So, the calculation consists in determining the required section of the sheet pile, in the depth of driving the sheet pile below the base of the pit, as well as in the selection of spacers.
Exists special instruction for builders, which will help you calculate sheet piling for various types soils (even in swampy or flooded areas).
Note! If you are installing sheet piling in sandy loam or sand, then in addition to basic calculations, you need to check the depth of driving the sheet pile itself below the bottom of the pit or the mark of its erosion according to the conditions of soil flow into the pit during rain or pumping water out of it.
Conclusion
Renting construction site fencing can help you save a lot of money and still meet all the requirements of safety engineers. In the presented video in this article you will find Additional information on this topic. Good luck!
— milestone zero cycle works in multi-storey construction. IN industrial scale digging of pits is carried out with the help of an excavator. According to the provisions of SNiP No. 3.02.01 "Earthworks", all pits with a depth of more than 2 m must be reinforced with sheet piles to prevent their collapse and flooding groundwater.
This article presents the technology of fencing pits with sheet piles. You will learn what types of sheet pile are used and how they are installed. Also, the design features of sheet piling will be considered and examples of calculations will be given.
When and why is it necessary to fence the pits with a sheet pile?
The need to strengthen pits with sheet piles is determined by safety requirements and SNiP standards, according to which the following types of pits are subject to reinforcement with sheet piles:
- all pits with a depth of more than 1 m in sandy soil;
- pits with a depth of 1.25 m in sandy loam;
- pits with a depth of 1.5 m in clay soil and loam;
- pits with a depth of 2 m in high density soils.
The functional purpose of sheet piling is to protect the walls of the pit from collapse, which can occur during pile driving at the construction site (more than 80% of multi-storey buildings stand on pile foundations).
Sheet piling technology can also be considered as an alternative to dewatering. The sheet pile used for the installation of the fence has groove locks, through which individual sheet piles are connected into a sealed, water-tight wall, which minimizes the risk of flooding the pit with groundwater.
Types of sheet pile for fencing pits
In modern construction practice, two types of sheet pile metal are used for fencing pits - Larsen sheet pile and pipe shunt. Wooden and reinforced concrete sheet piles are practically not used due to financial inexpediency.
The Larsen sheet pile is a trough-shaped profile, the length of which can reach up to 35 meters and the width up to 80 cm. There are several modifications of the Larsen sheet pile, which differ in terms of overall characteristics:
- sheet pile L4;
- sheet pile L5;
- sheet pile L5-UM;
- sheet pile Larsen "Omega";
- sheet pile L5.
The most commonly used sheet pile is L5, made of steel grades ST3KP or 16 KhG. The width of the L5 profile is 42 cm, the weight is 1 running meter. - 100 kg, weight 1 m 2 - 217 kg. The normative strength of sheet piling made of profile L5 is 800 kNm/m.
Fences from sheet piling are used in conditions of unstable soils prone to horizontal shifts, in which the walls of the trough-shaped profile do not have the required stability. Due to the larger cross-section of the pipes, which gives an increased area of pinching the sheet pile with soil masses, the moment of resistance and the strength of the pipe wall are much higher.
The diameter of sheet pile pipes varies within 530-1420 mm. Pipes used for fencing pits have a type marking unified in accordance with SNiP standards Т1420×12, wherein:
- T - tubular sheet pile;
- 1420 - diameter (mm);
- 2 - wall thickness (mm).
Like the Larsen sheet pile, the pipe sheet pile has slot locks located on the side contours of the pipes, through which the structures are connected into a solid wall. When installing fences, steel rotary elements are additionally used, through which the wall is given the required spatial configuration.
The widespread use of steel sheet piles in construction practice is due to the possibility of its reuse, which is not subject to reinforced concrete and wooden structures. Building company gets the opportunity to make a temporary sheet piling and, upon completion of the foundation work, dismantle the sheet pile and sell it on the secondary market, thereby reimbursing part of the financial costs. According to the norms of SNiP, the turnover of sheet piles and Larsen sheet piles can reach up to 20 cycles.
sheet piling calculation
The calculation of sheet piling is carried out by specialized specialists in accordance with the requirements of SNiP No. 2.09.03 "Design retaining walls". The purpose of fencing calculations is:
- determination of the required sheet pile size;
- determination of the depth of immersion of the sheet pile based on the compliance of the design stability and wall resistance with regulatory data;
- design additional measures to strengthen the sheet pile wall.
Calculation of the sheet pile wall resistance to overturning is carried out according to the formula: , in which:
- Ou - normative resistance;
- Oz is the pinching force of the sheet pile in the ground;
- K - coefficient. sheet piling operating conditions (depending on the type of soil);
- Cn - coefficient. safety margin (1.2).
Calculation of sheet piling strength is carried out according to the formula: , where:
- Lk is the value of the load per m2 of the fence;
- Pck is the design resistance of the wall;
- Du is the moment of resistance of the wall;
- K - coefficient. sheet pile work in the ground.
Calculation of the depth of piling is carried out according to the formula: T = t0 + ∆t, in which ∆t = :
- Fn is the diagram of load distribution along the sheet pile wall;
- qtO is the moment of maximum load on the fence, coming from soil pressure;
- d - coefficient. passive soil pressure on the wall (l - active impact).
For sheet piling, in each case, a flow sheet is drawn up, which indicates information and instructions for the implementation of work for the personnel performing sheet piling.
Routing created on the basis TTC ( standard map) №4-104-1 "The device of metal sheet pile walls" (an updated version of the TTK was released on 05/21/2015). The flow sheet for temporary sheet piling must be approved by the contractor's chief engineer and the person responsible for safety.
Vibration immersion of a tubular sheet pile (video)
Sheet pile wall installation technology
The sheet piling installation is carried out with the involvement of special construction equipment - pile drivers. COP is self-propelled machine on a caterpillar or wheel base, which is equipped with the equipment necessary for plunging the sheet pile.
The functional equipment of the copra includes:
- pile mast - steel guide, on which the submersible equipment and sheet pile structure are fixed;
- plunging mechanism - impact hammer or vibrator;
- winch blocks - for the concept and installation of the sheet pile in its original position.
There are three methods for mounting a tongue and groove: impact driving, vibration immersion and static indentation. In construction practice, the driving method is the most common - this is the most effective and inexpensive technology, however, the current SNiP prohibit driving sheet piles in dense building conditions, since the dynamic loads generated by the hammer during driving can cause deformation and destruction of the foundations of nearby buildings.
Vibration driving is a method in which the sheet pile is deepened into the ground under the influence of high-frequency low-amplitude vibrations. The vibrator generates vibrations that are transmitted to the sheet pile fixed in it, then the vibration passes to the soil layers in contact with the sheet pile, which, under the influence of vibrations, decompress, which leads to the deepening of the sheet pile under its own weight and the mass of the vibrator pressing on it.
STO-GK "Transstroy" -019-2007
ORGANIZATION STANDARD
Sheet piling type "Larsen". Application in transport construction
Introduction date 2007-04-10
Foreword
1 DEVELOPED by the Regional Public Organization "Scientific and Technical Association of Scientists and Specialists of Transport Construction", OJSC "Research Institute of Transport Construction (OJSC TsNIIS)" (candidates of technical sciences N.A. Efremov, L.N. Losev, engineers D.M. Dolganov, M.B. Smirnov, R.V. Stupnikov) by order of Transstroy Group of Companies LLC.
2 INTRODUCED by the Technology Development and Standardization Department of Transstroy Group of Companies LLC
3 ADOPTED AND PUT INTO EFFECT LLC "Group of companies "Transstroy" by order of April 09, 2007 N GK / PN-15.
4 AGREED JSC "LenmorNIIproekt" (out. N OGS dated 13.02.2007), Association "Gidroproekt" (out. N 3.2.4-20/284 dated 28.12.2006), JSC "SoyuzmorNIIproekt" (out. N 8/17 dated 11.01.2007), "Podvodrechstroy-4" Federal Agency for Marine and River Transport of the Ministry of Transport of the Russian Federation (ref. N 264 dated December 28, 2006), Transmost OJSC (ref. N 09 / 10-125 dated January 31, 2007), Department of Capital Construction of Russian Railways OJSC (ref. N TsUKSi-20/643 dated March 15, 2007)
5 The development of an organization standard is provided for by Article 13 of the Federal Law "On Technical Regulation" dated December 27, 2002 N 184-FZ.
6 This standard was developed in accordance with STO-GK "Transstroy" -002-2006 "Rules for the construction, presentation and designation in the development of standards for the organization of the Transstroy Group of Companies".
7 This standard uses TU 14-102-8-03*, LARSSEN profiles from HOESCH (Germany) and ESP VL from NIPON STEEL (Japan).
________________
* Specifications mentioned hereinafter are not given. See the link for more information. - Database manufacturer's note.
8 REGISTERED BY FSUE "Standartinform" on 11.04.2007 N 200/103119 and OOO "Group of companies "Transstroy" on 24.04.2007 N GK/ 218.
9 HOLDER OF THE ORIGINAL - Transstroy Group of Companies LLC
10 INTRODUCED FOR THE FIRST TIME
1 area of use
1 area of use
This standard applies to the construction of capital and temporary transport facilities for various purposes from the sheet pile of the "Larsen" type according to TU 14-102-8-03 "Pile L5-U. Nizhny Tagil Metallurgical Plant (NTKM)".
2 Normative references
This standard uses normative references to the following standards and normative documents:
GOST 380-94 Carbon steel ordinary quality. Marks.
GOST 427-75 Measuring metal rulers. Specifications.
GOST 7502-98 Metal measuring tapes. Specifications.
GOST 7566-94 Steel products. Acceptance, marking, packaging, transportation and storage.
GOST 15150-69 Machinery, instruments and other technical products. Versions for different climatic regions. Categories, operating conditions, storage and transportation in terms of the impact of climatic factors external environment.
GOST 25100-95 Soils. Classification.
GOST 12.3.009-76 SSBT Loading and unloading works. General requirements security.
GOST 17.1.3.13-86 Nature protection. Hydrosphere. General security requirements surface water from pollution.
GOST 17.4.3.02-85 Nature protection. Soils. Requirements for the protection of the fertile soil layer in the production of earthworks.
GOST 17.5.3.04-83 Nature protection. Earth. General requirements for land reclamation.
GOST 17.5.3.06-85 Nature protection. Earth. Requirements for determining the norms for the removal of the fertile soil layer in the production of earthworks.
GOST 6996-66 Welded joints. Methods for determining mechanical properties.
SNiP II-23-81 Steel structures.
SNiP 2.02.03-85 Pile foundations.
SNiP 3.01.04-87 Acceptance for operation of completed construction projects. Basic provisions.
SNiP 3.02.01-87 Earthworks, foundations and foundations.
SNiP 3.04.03-85 Protection building structures and structures from corrosion.
SNiP 3.07.02-87 Hydraulic marine and river transport facilities.
SNiP 12-01-2004 Organization of construction.
SNiP 12-04-2002 Occupational safety in construction. Part 2. Construction production.
SP 53-101-98 Manufacture and quality control of steel building structures.
VSN 34-91 Rules for the production and acceptance of work on the construction of new, reconstruction and expansion of existing hydrotechnical marine and river transport facilities.
TU 14-102-8-03 Sheet pile L5-U. Nizhny Tagil Iron and Steel Works (NTKM).
When using this standard, it is advisable to check the operation of reference standards and classifiers in information system common use- on the official website of the national authority Russian Federation according to standardization on the Internet or according to the annually published information index "National Standards".
3 Terms, definitions and abbreviations
In this standard, the following terms are used with their respective definitions:
3.1 anchor support: A support made of metal rods located in a soil mass, fastening and holding soils from collapse.
3.2 anchor pile (plate): A pile (slab) fixed in a soil massif and serving to hold a sheet pile wall and anchor lining.
3.3 bolter: The sheet pile wall of a sea or river berthing structure in the form of driven sheet piles connected on top with a special design.
3.4
vibrator: Vibro-impact construction machine for driving sheet piles into the soil massif.
3.5 soil array: An array of soil that provides the overall stability of the sheet pile wall according to the scheme of deep shear and rotational movement.
3.6 anchored sheet pile wall: A wall of sheet piles equipped with one or more tiers of anchor support.
3.7 unanchored sheet pile wall: Sheet pile wall without anchoring.
3.8 pile hammer: Impact construction machine for driving sheet piles into the ground.
3.9 sheet pile work: Aggregate technological operations(works) performed with sheet piles during the construction of a sheet pile wall.
3.10 sheet pile (sheet pile): Separate mounting element sheet pile wall, steel tongue type "Larsen".
3.11 sheet pile wall: Solid thin vertical or sloped wall from sheet piles driven into the ground (sheet piles); designed to absorb mainly horizontal loads and, above all, the pressure of the soil behind it.
3.12 PIC: Construction organization project.
3.13 PPR: Project of work production.
4 Classification (Basic parameters and dimensions)
4.1 A wall made of steel sheet piles of the "Larsen" type with anchor fastening (Figure 1) is designed to hold the soil mass from shear or rotational movement. The wall consists of a tongue-and-groove of the "Larsen" type, a "cap" or wheel breaker beam, a distribution beam, anchor rods and anchor piles.
Figure 1 - Sheet pile wall from "Larsen" sheet pile with anchor fastening
Figure 1 - Sheet pile wall from "Larsen" sheet pile with anchor fastening
1 - soil mass; 2 - tongue type "Larsen"; 3 - cap beam; 4 - distribution beam; 5 - anchor rod; 6 - anchor pile
4.2 The anchored wall of the "Larsen" sheet pile is equipped with anchor devices that prevent the movement of the upper end of the sheet pile. An anchored wall structure may have one or more tiers of anchors.
The depth of driving and the section of the sheet pile, the design of the anchor lining, anchor piles and the number of tiers of anchors are taken in accordance with the project.
The most common walls are made of sheet piles of the "Larsen" type with one tier of anchors, erected at a watercourse depth of 5-14 m.
4.3 An anchorless wall (Figure 2) has more simple design. The wall consists of a row of sheet piles hammered into the ground, the top of which is united by a capped timber.
The free height of the anchorless wall and the depth of pile driving are determined by calculations, in accordance with the requirements of the project. Under ordinary conditions, the free height of the anchorless wall does not exceed 6.5 m.
Figure 2 - Sheet pile wall of "Larsen" type sheet pile
Figure 2 - Sheet pile wall of "Larsen" type sheet pile
1 - soil mass; 2 - tongue type "Larsen"; 3 - cap beam
4.4 Sheet piles are made from 6 to 24 m long. For the production of sheet piles, carbon steel with a yield strength of up to 420 MPa and normalized impact strength at a temperature of minus 40 ° C is used.
4.5 The sheet piling is manufactured at the Nizhny Tagil Iron and Steel Works.
4.6 The assortment and characteristics of the "Larsen" sheet pile and sheet pile walls are given in Appendix A.
4.7 Domestic sheet pile walls made of hot-rolled trough sheet piling of the "Larsen" type are not inferior to similar foreign profiles "LARSSEN" of the company "HOESCH" (Germany) and "ESP VL" of the company "NIPON STEEL" (Japan), which is confirmed by the results of a comparative analysis given in Appendix B of this Standard.
4.8 Comparative characteristics of sheet pile walls of "Larsen" type sheet pile are given in Appendix B.
5 Transportation and storage of sheet piles, anchor rods and piles
5.1 Larsen-type sheet piling, anchor rods and piles can be transported by all types of transport in accordance with the transportation rules applicable to the specific type of transport.
5.2 Within the water area, "Larsen" sheet piling, anchor piles and rods should be transported on deck barges, pontoons having the necessary buoyancy and stability, checked by calculation for the perception of concentrated loads from the mass of the sheet piling. It is allowed to transport sheet piling on the deck of floating cranes for a distance of up to 4 km in a water area protected from waves.
5.3 Transportation and storage of "Larsen" sheet pile, anchor rods and piles in terms of exposure to environmental climatic factors must comply with the requirements of GOST 15150-69. It is allowed to store sheet piles, anchor piles and rods in the open air.
5.4 "Larsen" sheet piles may be stored in piles, the height of which excludes residual deformations of structures.
5.5 When storing, loading, transporting and unloading "Larsen" sheet piles, anchor rods and piles, linings and slinging devices should be used to prevent permanent deformation and damage to the locks and ensure the preservation of their shape.
5.6 When storing sheet piles of the "Larsen" type, anchor rods and piles, good visibility of the marking of structures should be ensured. At the request of the customer, the following types of marking can be applied:
- color markings in the head of each sheet pile, defining the profile, length and steel grade;
- stickers containing the customer's name, destination, order number, profile type and length.
5.7 The dimensions of passages and driveways in the place of storage of structures between stacks or individual structures must comply with the requirements of building codes.
6 Acceptance, preparation and storage of "Larsen" sheet piling, anchor rods and piles
6 Acceptance, preparation and storage of "Larsen" sheet piles, anchor rods and piles
6.1 Each batch of Larsen sheet pile, anchor rods and piles received at the construction site must be accompanied by documentation (passport) in accordance with the requirements of SNiP 12-01-04, VSN 34-91, GOST 7566-94, TU and have certificates of conformity that meet the requirements of the Federal Law "On Technical Regulation" (N 184-FZ, Chapter 4).
6.2 The document (passport) on the quality of the Larsen sheet pile, anchor rods and piles must contain:
- name of the manufacturer, its address and trademark;
- designation of sheet piling, anchor piles and rods;
- number of the passport and the date of its compilation, information about the steel grade of sheet piles, anchor rods and piles;
- product parameters;
- type of anti-corrosion coating and its characteristics;
- the number of delivered products;
- a passport signed by the head of the QCD or other responsible representative of the manufacturer;
Attached to the quality document:
- executive drawings of shipped products;
- a list of documents on the quality of materials used for the manufacture of products;
- copies or numbers of diplomas (certificates) on the qualifications of gas cutters and welders who manufactured the products;
- a list of results of quality control of welded joints in products.
6.3 Sheet piles and anchor rods are allowed for acceptance if their dimensions and shapes of profiles differ from the design ones within the limits specified in the relevant specifications and regulatory documents.
6.4 The protective anti-corrosion coating of the anchor rods and anchor piles should have no more than two delaminations with a surface area of up to 20 cm per 1 m. Deviations in the thickness of the protective coating should not exceed ± 10%. When checking the quality of protective coatings, documents are considered that characterize the constituent components in relation to compliance with their shelf life.
6.5 For electric welding of sheet piles, anchor rods and piles at the construction site, welding materials should be used in accordance with the requirements of the project and SNiP II-23-81.
6.6 Welded joints must be made in accordance with the requirements of GOST 5264-80 and GOST 14771-76.
6.7 Welding joints of the "Larsen" sheet pile are performed in accordance with the project from the condition of ensuring equal strength of the butt joint to the main section. Welding joints of adjacent sheet piles are allowed to be no closer than 2 m from one another, while the stresses in this section should not exceed 50% of the calculated ones.
6.8 Before immersion, on all sheet piles, check the geometric dimensions of the interlocks, the straightness of the shape and the possibility of mutual unhindered passage of adjacent interlocks.
6.9 It is recommended to check the geometrical dimensions of the tongue and groove locks on the stand and using templates no less than 2 m long. The revealed defects of the "Larsen" type tongue locks (bends, dents) must be corrected by mechanical straightening. For one sheet pile, it is allowed to replace one defect of the lock in a section no longer than 0.5 m.
6.10 On each sheet pile, a serial number must be applied with indelible paint, the length and depth of immersion of the pile into the ground according to the project are indicated.
6.11 Larsen sheet piling is normally supplied without mounting holes. If necessary, sheet piles can be provided with mounting holes along the center line of the pile. The mounting hole of a sheet pile of the "Larsen" type of a standard size has a diameter of 50 mm and is made 250 mm from the end on the longitudinal axis of the trough profile.
6.12 All lifting and transport operations must be performed in accordance with the requirements of the PPR, taking precautions against damage to the anti-corrosion coating, locks and the occurrence of other defects in structural elements.
Translation of sheet pile wall elements from horizontal position vertical must be carried out using traverses.
6.13 Places for storing the stock of elements must be chosen as close as possible to the headframes or cranes. Elements should be shifted into stacks in such a way as not to overturn during slinging.
Places for storing sheet pile wall elements should be convenient for the passage of cranes and vehicles and for loading and unloading operations.
7 Preparatory work
7.1 Structures using a sheet pile of the "Larsen" type should be erected in accordance with the requirements of the working documentation, SNiP 3.01.01-85, SNiP 12-01-04, VSN 34-91, POS, PPR, as well as this standard of the organization. All deviations from the project documentation must be preliminarily agreed with the design organization.
7.2 Immersion of a sheet pile of the "Larsen" type must be preceded by the execution and acceptance of the following works under the act:
- checking the availability of a set of design and estimate documentation at the facility; familiarization of engineers and workers with design documentation for the construction of a sheet piling wall and PPR;
- breakdown and fixation of the main axes of the structure, removal of a high-rise benchmark to the work area, creation of a construction network, fixing the boundaries of the construction site in nature;
- acceptance ( input control- sheet piling type "Larsen" and other elements of the sheet pile wall and their corresponding preparation for immersion;
- preparation and testing of mechanisms and machines (lifting equipment, hammers, vibrators) and auxiliary devices (templates, guides, conductors) intended for use in the construction of a sheet pile wall;
- depth measurements at the construction of a berthing facility in the sheet pile wall construction area in order to check the compliance of the underwater slope with the project and clarify the scope of work on backfilling the behind-the-wall space. In the event of a significant deviation of the actual slope profile from the design one, it is necessary to bring it to the design position by additional development or topping up the soil;
- preparation of the soil base (removal and storage of the vegetation layer), examination (including by geophysical methods, etc.) of the soil massif for the presence of stones and boulders in the alignment of the sheet piling and anchor piles (if they are accepted in the design documentation in the form of steel pipes);
- diving inspection of the bottom of the water area near the berth in order to identify and remove objects that may prevent the immersion of sheet piles and anchor piles;
- arrangement in accordance with the PPR of access roads, storage areas, power lines, outdoor lighting of the construction site, service and amenity premises and a rescue post.
7.3 When building a sheet pile wall in marine conditions, on a river or other water body, the bottom of the water area is examined by divers or by other methods: underwater television installations and similar equipment. If any objects are found that prevent the sheet pile from sinking into the ground, measures are taken to eliminate these obstacles.
7.4 Trial immersion and extraction of the "Larsen" sheet pile (if it is provided for in the project) is carried out according to the program drawn up by the design organization in order to develop the technology for the production of work, clarify the design of the slinging device, conductors, templates, the operating mode of the main and auxiliary equipment, definitions of length and bearing capacity piles type "Larsen".
8 Selection of sheet piling and anchor pile driving equipment
8.1 The method of driving "Larsen" sheet piles and the equipment used must comply with the decisions of the POS, PPR and design documentation for this structure and the instructions of this Standard. Submersible equipment should be selected based on the accepted method of work, design documentation, local technological and natural conditions of this section of the Standard.
8.2 A set of equipment for the construction of a sheet pile wall is selected based on the results of the analysis of the initial data, the main of which are:
- the purpose of the sheet pile wall, the requirements for ensuring its safety, temporary and operational loads;
- engineering and geological conditions at the construction site;
- characteristics of sheet piles of the "Larsen" type, including length, cross-sectional area;
- hydrometeorological conditions (water depth, current speed, water level fluctuations, wind rose, protection of the water area from waves);
- local technical conditions (availability of equipment, electricity, transport routes, etc.);
- the accepted technology for the production of works (the sequence of sheet pile driving, the time of work, etc.).
8.3 When erecting structures containing sheet pile walls, the Larsen type sheet pile is immersed in the ground with hammers or vibratory drivers. Also allowed combined scheme plunging the sheet pile into the soil massif (vibration plunging with hammer finishing).
8.4 The type of hammer for driving sheet piles of the "Larsen" type and anchor piles should be selected in accordance with the instructions of SNiP 3.02.01-87 (Appendix 5) and Appendix B of this Standard.
The type of vibratory driver for driving "Larsen" sheet piles and anchor piles should be selected in accordance with the instructions of SNiP 3.02.01-87 (Appendix 6) and Appendix D of this Standard.
8.5 The criterion for the correct choice of the driving mechanism is the successful trial driving of at least three "Larsen" type sheet piles in the most characteristic points of the construction site.
8.6 In case of severe driving conditions for Larsen-type sheet piles and anchor piles (failure during driving less than 0.2 cm or vibration penetration rate less than 2 cm/min), it is necessary to take additional measures to facilitate sheet pile driving, including washing sheet piles, making a ground cut.
9 Driving and retrieving sheet piles and anchor piles
9.1 During the construction of the sheet pile wall of a structure, a sheet pile of the "Larsen" type should be loaded using a guide device, the design of which is developed depending on the type of structure, local conditions, POS and PPR.
It is recommended to use a device (Figure 3) in the form of two parallel beams spaced at a distance (Appendix A) plus a gap of no more than 0.01-0.02 m as a guide when constructing a sheet pile wall.
Figure 3 - Inventory scaffolding-conductor for driving sheet piles of the "Larsen" type
Figure 3 - Inventory scaffolding-conductor for driving sheet piles of the "Larsen" type
1 - guide pins; 2 - lighthouse piles; 3 - clogged pile type "Larsen", 4 - wooden fuses; 5 - wooden scaffolding, 6 - railing; 7 - fastening guides
Figure 4 - Device for protecting anchor rods and sheet piles and a guide screen for backfilling a stone prism
Figure 4 - Device for protecting anchor rods and sheet piles and a guide screen for backfilling a stone prism
1 - tongue type "Larsen"; 2 - distribution belt; 3 - anchor traction; 4 - protective structure; 5 - guide screen; 6 - wooden nozzles; 7 - anchor pile
Floating guides, as a rule, are fixed on at least four cool piles. The value of their limiting movement should not exceed 0.02 m.
If the length of a sheet pile of the "Larsen" type during driving exceeds twice the distance from the bottom of the water area to the guides, they are arranged in two or more tiers. The distance between tiers is taken at least 3 m.
To ensure the preservation of the anti-corrosion coating, each sheet pile must be equipped with adjustable rubber-coated rollers during immersion.
9.2 Sheet piles of the Larsen type are usually loaded with grips. The grip length depends on the performance of the equipment and hydrological conditions at the construction site and is determined in the project documentation.
9.3 When driving the first sheet and anchor pile, Special attention pay attention to the observance of verticality or a given inclination. The correctness of sheet pile and anchor pile driving is controlled in two planes and subsequently the control is repeated at least through every second sheet pile or anchor pile.
9.4 If there are weak soils in the soil massif and at the base of the sheet pile wall, it is possible for the previously driven sheet pile to go below the design mark. To prevent this phenomenon, sheet piles sunk to design marks are recommended to be combined by welding.
9.5 More powerful sheet pile driving equipment or additional tools such as flushing should be used if the sheet pile does not reach the design mark. In this case, preference should be given to a hammer with a heavier impact part.
9.6 When driving a sheet pile and an anchor pile with a vibrator, it is necessary to ensure a rigid and permanent connection between the sheet pile and the vibrator. For driving Larsen sheet piles, vibratory drivers with hydraulic caps should be preferred.
9.7 In the process of vibratory driving of the sheet pile, the position of the rope and the crane hook on which the vibratory driver is suspended should be monitored.
When working with a vibratory driver equipped with a shock absorber, the crane hook lowering speed must prevent the vibrator from hanging.
When operating a vibratory driver without a shock absorber, the speed of the crane's descent must not cause a brake on the sheet pile driving.
9.8 When driving sheet piles of the "Larsen" type with a vibrator equipped with a shock absorber, the underfeeding of sheet piles can be eliminated by raising the sheet pile by 0.5-1 m once or twice and then immersing.
If underdipping is caused by the sheet pile meeting with an obstacle, the immersion process should be stopped and the issue resolved jointly with a representative of the design organization.
9.9 When performing work on driving "Larsen" type sheet piles and driving anchor piles, a record of driving sheet and anchor piles should be kept. According to the log, a summary sheet of sheet piling is compiled. The journal should be accompanied by planned and profile schemes design and actual position of sheet piling and anchor piles.
9.10 Shearing of sheet piles may be carried out only with the permission of the representative of architectural supervision and (or) the customer, about which an appropriate entry must be made in the work log.
9.11 Driving of sheet piles and anchor piles with hammers and their immersion with vibratory drivers should be carried out using special caps in the form of distribution plates, equipped in the upper part with an annular cage for placing a shock absorber in it, and in the lower part with a system of protrusions for fixing the sheet pile head and determining the position relative to the hammer.
The cap is designed to evenly redistribute the load on the sheet pile when hit by a hammer and to mitigate the impact impulse.
9.12 The planned dimensions of the cap plate and its lower surface must ensure close contact with the end surface of the tongue over the entire area.
9.13 The shock absorber is made from a solid bar of a tree trunk, from rubber, or dialed in height from individual elements square section.
Estimated service life of the shock absorber hard rock wood - up to 8000 strokes, and up to 5000 strokes when it is made from pine.
9.14 The minimum failure of the sheet pile and anchor pile during driving should be 0.2 cm, but not less than that given in the passport of the hammer manufacturer and in the instructions for its operation.
9.15 Washing facilitates the driving of sheet piles and anchor piles to the design marks. This method is allowed for use at the construction site if the distance between the sheet pile wall and the existing structures is at least twice the depth of the sheet piles.
9.16 The use of flushing is most effective in combination with vibratory driving of sheet piles. Washing parameters should be determined on the basis of appropriate hydraulic calculations, taking into account the rate of soil erosion and water consumption for its hydrotransport.
9.17 To extract "Larsen" sheet piles, it is recommended to use cranes with a lifting capacity of 500 kN or more, cranes equipped with vibratory loaders, impact sheet pilers, double-acting hammers.
A combined method of pulling out sheet piles of the "Larsen" type in combination with jetting is also recommended.
9.18 Soil resistance when pulling out "Larsen" type sheet piles is composed of resistance in interlocks, sheet pile weight and friction on the lateral surface and in interlocks.
The efficiency of sheet pile pulling out increases with preliminary wetting of the soil mass at the work site.
10 Drainage and drainage
10.1 To improve the reliability of work at the stages of construction and operation of sheet pile walls, a set of measures should be taken to organize the removal of surface and ground water from the construction site.
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At the very beginning of construction, the soil is in a soft, uncompacted state. So that in case of violation of the integrity of the soil, the surrounding buildings or the landscape do not suffer, the foundation pit is strengthened with a sheet piling. Most often, sheet piling is installed on large pits.
When building a private cottage or house, the need for fencing the pit arises infrequently: if there are loose unstable soils on the site or construction work begins during the rainy season. Then the soil may begin to be washed off into the pit under precipitation. High-quality sheet piling will not only help retain soil, but also retain water.
What is sheet piling
This is a series of piles driven into the ground and forming a fence. The use of such structures allows you to create a safe area for conducting further work. Often sheet piling is left in the ground to protect, for example, the foundation from groundwater.
The piles are driven into the ground tightly to each other. Due to the density of placement and the grouting of the joints, the sheet piling becomes completely waterproof.
Types of sheet piling
There are several technologies for sheet piling.
Which tongue to choose?
The choice of piles for sheet piling depends on the future load on the fence. Therefore, you first need to calculate the load, and only then choose the appropriate piles. Then the selection method suitable option: for the price, ease of transportation, the final option is selected.
Piles are selected according to the following parameters:
- Durability ─ the period of operation of metal piles depends on the operating conditions, PVC piles are almost eternal.
- Quick installation - plastic piles are smooth, they have a low coefficient of friction, so installation is 2 times faster than other piles.
- Weight - PVC piles are not heavy, so their loading / unloading and transportation are cheaper.
How to install sheet piling
For the installation of sheet piling during construction on your site, you can rent Larsen sheet piles, which are very convenient for installation. They are easily driven into the ground and are no less easy to dismantle. However, in order to install Larsen sheet piles, you will need special equipment - a vibratory pile driver and a team of 3-4 specially trained professionals. At the end of the work related to the strengthening of the soil, sheet piles are removed from the soil.
The vibratory hammer can be replaced with a manual vibratory hammer. A manual vibratory hammer is not the cheapest equipment, but if a lot of work is planned on the farm related to driving piles - installing a fence, pile foundation For outbuildings, strengthening the banks of the pond, etc., then it can be purchased. Otherwise, like Larsen sheet piles, you can rent it.
With the help of such a jackhammer with an impact head, the sheet piles are immersed to the desired depth. Due to the significant impact force of the hammer, the installation time of the sheet piling is reduced, and the need for heavy equipment disappears.
Larsen sheet piles are driven into the ground sequentially: the second section is inserted from above into the groove-lock of the first section. At the same time, it should be rotated 180 degrees relative to the previous one, forming a continuous structure.
How to install a wooden sheet piling with your own hands
It is possible to adapt an unedged board with a thickness of at least 4 cm to strengthen the walls of the pit on the quicksand. Such formwork is tightly fitted to each other during installation. The boards are fastened with transverse bars. If during the installation of sheet piling wooden fence constantly incoming wet soil interferes with work, a drainage pump must be used. After installing the sheet piling, the soil will remain behind the walls, and the water will flow down to the bottom of the pit.
To connect and strengthen the boards, beams and corners are installed. To ensure the rigidity of the fence from the inside, it is reinforced with spacers from a bar 10 cm by 10 cm. The width of the board for the tongue and groove must be at least 15 cm. The length of the boards depends on the size of the pit. The lower pointed ends of the sheet pile-boards are driven into the ground to the depth of the pit with a sledgehammer.
Despite the apparent ease of installation, it is better to dig a pit, choose the type of sheet piles, install sheet piles with a team of qualified professionals and special equipment.
This is one of the varieties of rolled metal, developed in its form at the beginning of the 20th century. The product has wide application from construction to hydraulic engineering. The special shape of the profile makes the tongue best solution for many construction tasks.
Larsen sheet pile device
Sheet pile is a hot rolled product made from steel with a high carbon content. The shape of the profile in cross section resembles a trough with edges equipped with locks - they allow you to fix the products together when installing vertical enclosing structures, for example, supporting walls.
The production control of Larsen sheet pile is regulated by GOST 4781-85 “Hot-rolled steel profiles for sheet piles. Specifications". There is no separate standard for the product, so manufacturers are guided by the developed specifications.
The document presents standard sizes sheet piling, the grade of steel used for the production of steel, the procedure for checking the quality and acceptance of products and other important parameters.
Varieties
The product is used in different areas of construction, so the technical characteristics, appearance the profile and grade of steel used differ from type to type.
Sheet pile Larsen L4
The profile is made of steel 16HG (ST3KP). Its characteristics:
- useful width of the product in the center of the lock - 405 mm,
- wall strength is 517-518 kN/m;
- thickness of inclined faces - 9.5 mm;
- allowable resistance 1 p.m. supporting wall - 2200 cm³/m;
- weight of Larsen L4 sheet pile - 74 kg/m;
- weight of 1 m² of construction - 182.7 kg.
Larsen sheet pile l4 is produced at 2 factories:
- Russian Mining and Metallurgical Company;
- "DMK" (Ukraine).
The product is widely distributed in Russia and the CIS countries, it can be bought from various suppliers in the primary and secondary markets.
Sheet pile Larsen L5
For the manufacture of this rolled steel, ST3KP steel is used. This is a more powerful profile than L4:
- useful profile width between locks - 420 mm;
- wall strength - 696…800 kN/m;
- allowable resistance 1 p.m. supporting wall - 2962 cm³/m;
- weight of Larsen L5 sheet pile - 100 kg/m;
- weight of 1 m² of construction - 238 kg.
Like L4, L5 sheet pile is produced by the Ukrainian DMK and the Russian Mining and Metallurgical Company. You can buy the product throughout Russia at reasonable prices from different suppliers and intermediaries. On sale you can find rolled VL607 - this is an analogue of L5 sheet pile from the Czech company Evraz.
Sheet pile Larsen L5-UM
This representative of rolled products of this type differs from its predecessor in the quality of the steel used for the production - it is resistant to corrosion, it contains copper.
- Useful profile width between locks - 543 mm;
- wall strength - 906 kN/m;
- thickness of the inclined edge - 11 mm;
- allowable resistance 1 p.m. supporting wall - 3555 cm³/m;
- weight of Larsen L5-UM sheet pile - 114 kg/m.
Other types
Larsen sheet piles differ not only technical specifications, but also the shape of the castle:
- S-profile;
- L-profile;
- Z-profile.
In all cases, the lock forms a tight connection between adjacent profiles.
For different purposes, beams made of non-metallic materials are used:
- plastic;
- reinforced concrete;
- tree.
Nevertheless, steel sheet piles are used most often and are in demand.
Application area
Larsen sheet piling is used in civil engineering and in the arrangement of hydraulic structures for various purposes:
- strengthening of foundation pits for the period of installation work;
- protection of pits from filling with groundwater - the connection of the sheet pile is completely hermetic and retains its properties for several decades;
- strengthening the walls of tunnels, highways and roads local importance;
- fixing coastlines and protecting them from erosion;
- arrangement of dams, dams, locks, moorings, etc. and their repair;
- construction treatment facilities;
- strengthening soils prone to slipping.
The tongues, connected by locks, form a sealed and durable wall that can take significant loads. Products are immersed in the ground, leaving a fence of the required height above ground level. The arrangement of sheet pile walls is much more profitable than the installation of concrete and reinforced concrete structures, therefore, metal profiles are most often preferred in cases where it is necessary to restrain the pressure of water and soil.
Installation
The method of immersing the Larsen sheet pile depends on the length of the product and the characteristics of the soil. There are 3 methods of mounting profile piles:
- clogging;
- vibration immersion;
- indentation.
The sheet pile is inserted into the ground according to the design position, the next one is buried upside down by 180 ° relative to the previous one to enable the mounting lock to be closed, and so on.
hammering
This method is used outside urban areas, since the vibration transmitted to the ground has a destructive effect on the foundations of adjacent buildings and structures.
Clogging is carried out by means of special equipment - copra. This machine is equipped percussion mechanism, the impact force of which on the pile being driven is regulated depending on a number of factors (sheet pile, soil parameters).
Larsen sheet piling is the fastest and cheapest method of deepening steel retaining walls.
vibration immersion
The second most popular method is vibration immersion. This method is used in cases where it is not possible or necessary to clog the elements of the supporting wall (in reservoirs, on coastlines, on soft soils saturated with water).
Vibration is provided by a mechanism that emits low frequency vibrations. It is hung on excavators, cranes and other equipment.
How the dive works:
- the sheet pile is attached to the vibration mechanism by means of slings;
- direct the rack to the design position;
- the installation presses on the pile, emitting vibration, which helps the steel product sink into the ground.
The method does not have a significant effect on the soil, however, its use within the boundaries of dense buildings is limited. In addition, the method has significant disadvantage- high cost compared to clogging.
indentation
The most expensive and the only sheet piling method approved for use in urban areas is indentation. The process is carried out by a special pile-pressing installation (SVU) on caterpillar tracks. The sheet pile is attached to the movable mechanism in a vertical position, the profile is immersed in the ground to a predetermined depth.
Dismantling
When supporting wall becomes unusable or the need for it disappears, it is dismantled. The extraction of the Larsen sheet pile is carried out using a vibrating unit. The use of a crane alone is inefficient - the friction forces in the soil are significant, and only short-amplitude oscillations can weaken them.
The sheet piling is fixed in a vibration unit suspended from a crane and the vibration generator is turned on, the pulling force is gradually increased.
As a rule, the cost of even used sheet piles exceeds the cost of their dismantling, so the work pays off well. For this reason, organizations that are engaged in the extraction of sheet piles themselves pay their customers the difference in prices, the latter automatically solve the issue of selling unnecessary profiles.
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