The development of a plot of land on difficult terrain requires the construction of reinforcing structures. They will help set up a garden on slopes, prevent soil collapses near the building and become a decorative decoration for the yard. Using retaining walls in landscape design, you can turn steep slopes into a landscaped terrace system. The site is divided into zones with straight ledges in the form of steps. Different materials are used to build the structure, but in order for them to cope 100% with their task, it is necessary to follow accurate calculations and a number of rules, which we will talk about today.
Strengthening slopes and slopes at the dacha
Dacha plots can be of the most intricate shape, not only in terms of their borders, but also in terms of topography. Often, these are not just flat areas on which you can build houses and plant plants, but also not particularly convenient ones, with hills, slopes and even serious cliffs. If we talk about the standard six hundred square meters within the boundaries of the cooperative, then practically no such problems arise, but if the dacha is located outside the city, then it is often built near a forest or river. But here the terrain can change very much. That is why DachaDecor.ru today talks about the topic of slopes and slopes that need to be strengthened.
Drainage and drainage systems
Now it's time to pay attention to another important element in the construction of a supporting wall. A strong foundation is good, but not enough. After all, even the strongest foundation can be destroyed by excess moisture accumulated on the inside of the structure. In view of this, the organization of the drainage system and drainage are the main components of the entire construction project, regardless of the material, dimensions or shape of the retaining wall.
If we talk about the structure of the drainage system, then it is usually organized in a transverse, longitudinal or combined form.
In order for the desired structure to last for a sufficiently long time, waterproofing is provided during its design. In this case, roofing felt is often used, installing it in a double layer, or you can use a hydrobarrier film. Experts most often recommend that if the soil is fairly dry, treat the inside surface of the wall with bitumen mastic or resin in combination with machine oil.
Plan diagram of a retaining wall
Why strengthen slopes and slopes?
Many people have avoided this task for years, and nothing... that’s what those who are used to living in the classic dacha mode will say - coming here in the summer to plant potatoes, and leaving in the fall with the harvest, until spring. Well, we are a little different, and our dacha should not only be productive, but also very attractive. And also convenient, safe and extremely practical. This means that everything that we build, create and even plant should be useful for many years. And sometimes this requires additional care.
Strengthening slopes, slopes and banks is one of these concerns, especially for summer residents who own areas with difficult terrain. Here, there may be slides of soil, slides from the top point and directly into the yard or garden, erosion of the bank and washing out of the same lawn, melting of snow into a mud pile during the spring melt, and breakdown of plants. These are just a couple of reasons that already draw attention to the complexity of the problem. But it also happens that not only does a snow cap fall from a steep hill at a dacha, bringing with it a little dirt and roots, but also multi-ton, extremely dangerous landslides that we would like to prevent.
It is clear that such precedents take place in mountainous areas, or in areas of forested areas and even former construction sites, where there are hills, ravines, pits and other non-standards that lead away from a simple and flat topography. But at our dachas there are also places that should be treated with caution. Therefore, let's study methods that will help qualitatively strengthen the slopes with our own hands.
How to strengthen a small slope with plants
If the slope does not exceed 8-10%, it is most advisable to strengthen it with plants with a strong root system. Thanks to the planting of grasses, cereals, shrubs and small trees, living soil reinforcement is created inside the soil, which prevents landslides and unauthorized distortion of the relief.
In this regard, you should not remove plants on slopes, if there are any in your dacha. At first, after uprooting, changes may be observed, as you will disrupt the soil bond. But problems may arise in the future, when a lack of plants gives problem areas the opportunity to quickly deteriorate.
Strengthening with biomats
Plants can also be used to secure slopes up to 45%, but there are much more risks here. They exist because plants take a long time to form a root system, which must reinforce the soil. Atmospheric factors also work here - the presence of precipitation, wind, humidity associated with bodies of water located nearby or on the slope itself, as well as the groundwater level and even tremors.
Therefore, it is recommended to use additional reinforcement in the form of biomats, which consist of coconut fibers or straw applied to a layer of cellulose.
Biomats are laid on the surface of the cleaned slope and evenly fixed. Next, seeds of various plants are sown over the entire area of the material, which in the near future should create a single layer with the biomats. These can be not only special flowers and herbs, but also plants for landscape design of your dacha area that you yourself have chosen.
Installation nuances
Reinforcement
The walls are reinforced with spatial reinforcement frames assembled from flat reinforcing meshes, the longitudinal rods of which have a diameter of 8-10 mm, and the transverse ones - 12-14 mm. At the intersection points, the rods are welded to each other in all places using resistance spot welding or tied with wire. The reinforcement diagram is shown in the photo.
Scheme of reinforcement of thin-walled retaining walls.
Important! To obtain the integrity of the entire retaining wall, the front slabs are connected to each other by single rods with a pitch of 500-600 mm, which are welded or tied to the transverse reinforcement of the distribution grids, forming a spatial frame.
Substrate preparation and expansion joints
If there are heavy soils at the base, and the depth of soil freezing is less than the level of the foundation on the lower side, then the weak soil is completely removed and replaced with a cushion of crushed stone or sand. However, there are differences in the structure of the bases and seams depending on the design solution and the chosen material:
With the finished version:
- The prefabricated foundation slab is mounted exclusively on a crushed stone base compacted into the ground. Its minimum thickness shall be taken to be 100 mm and the width of the base shall be designed so that it extends beyond the edges of the foundation slab by at least 150 mm on each side;
- Expansion joints (a structural section in structural elements that divides the structure into separate compartments) must be made along the entire length of the wall every 30 m. If the slabs are monolithic prefabricated, the joint spacing is 25 m.
For monolithic execution:
- The foundation slab must be laid on a concrete leveling base 100 mm thick and protrude beyond the foundation by at least 100 mm. To prepare concrete, take concrete grade M50;
- Expansion joints are made every 25 m when using reinforced concrete; in concrete structures without structural reinforcement - every 10 m; and if there is structural reinforcement, the step will be 20 m;
Important! The width of expansion joints should be 30 mm. They are formed by introducing a resin panel into the structural area. In addition, if the soil along the entire length of the wall is heterogeneous, expansion joints are organized in such a way that the base of the foundation lies in the same type of soil, and the spacing of the temperature-sedimentation joints is reduced.
Advice! In the longitudinal direction, walls are erected horizontally or with a slope of no more than 0.02. If the slope is greater, perform the longitudinal walls in steps. And in the transverse direction, the maximum slope can be 0.125 towards the backfill. The slope values are regulated by clause 5.1.3 SP43.13330.2012.
Fixation with geotextiles
Geotextile is a dense material based on polyester or polypropylene fibers. It is artificial, but is excellent for a wide variety of jobs, as it is quite durable and water permeable.
Thanks to geotextiles, it is possible to strengthen slopes of 173% or 60°. Geotextiles are laid out along the slope and subsequently reinforced with special anchors. After final installation and fixation, you can always plant plants on top of the material, or decorate the slope with stone, gravel, or tiles.
Strengthening with geomats
Another way to make a high-quality and reliable slope is the use of geomats. This material, which consists of several layers of polypropylene gratings, even somewhat resembles a washcloth.
But the positive side is that, along with high strength, geomats are also permeable to air, water and plant roots. That is, laying geomats on a slope will not only qualitatively strengthen it, but also, as in previous cases, plant all the necessary plants on top of the material, which will soon create a uniform and fairly dense layer.
An additional advantage of the material is the ability to use it on slopes up to 70°.
Fatshedera - care:
Lighting:
In indoor conditions, Fatshedera requires good lighting. Fatshedera also requires direct sunlight in the morning and evening, but the plant should only be moved into the shade during the day and especially during the hot summer period. Particular attention should be paid to Fatsheder lighting if it is located on a south window.
Temperature:
Fatzchedera is a fairly heat-loving plant. In winter, the temperature should not fall below 4-6 ° C. For Fazcheder, the preferred ambient temperature is 22-25 ° C in summer.
Humidity:
When growing Fazchedera at home, the plant requires a fairly humid environment, especially if the temperature exceeds 18-20oC. This requires regular spraying of the plant and washing of the leaves.
Feeding:
Feeding for Fazcheder must be done several times in the summer with mineral fertilizers. The substrate used must always be moist.
Transfer:
Fazcheder must be replanted in March, in slightly larger pots, in a mixture of peat soil and sand (4: 1: 1). It is also necessary to remove damaged parts: shoots, foliage and inflorescences.
Reproduction:
Fatscheder is propagated by apical cuttings. Fatshedera can also reproduce through layers of air. In summer, cuttings are taken and planted in a very humid place in a mixture that should consist of peat and sand (1: 1). Already rooted cuttings are finally transplanted into pots only next spring.
Some features:
When growing in an apartment, you can add shine to the foliage of Fazcheder using a shine solution, while avoiding excess of it.
Application of geogrid
The geogrid allows you to work with exactly the same angle. It is a material made of polyester or glass, which is quite easy to work with.
Geogrid will help to quickly compact the top layer of soil, which is most susceptible to landslides and various types of destruction, as well as decorate it after major work.
The geogrid is laid in the following way: initially, the material itself is laid on a more or less prepared surface. Next, soil, sand or even crushed stone is poured into the geogrid cells. But it is most correct to place fertile soil in the cells, where plants can be planted immediately. This will make it possible to obtain the highest degree of strength of the slope strengthening in just a few months.
How to make an underground part. Which foundation to choose
Retaining walls with a height of more than 30 cm must have a reliable foundation. The main principle that should not be forgotten when laying a foundation: if the soil is soft and unstable, the depth of the foundation should be increased.
Foundation depth and support height taking into account soil looseness
- If the soil is dense enough, the depth of the foundation and the height of the top of the support (from the ground) should be in a ratio of 1: 4.
- In the presence of moderately loose soils, the depth of the foundation should be 1/3 of the height of the support.
- If the soil is loose and soft, the depth of the foundation should be 1/2 of its height.
- Concrete, crushed stone, gravel compacted with heavy clay or cement should form the foundation.
Application of geogrid
Experts say that geogrid is more reliable in use than geogrid. This material is a cellular frame that stretches over the surface. After laying on a slope, the geogrid can be fixed in different ways, but the most popular is fixation with fillers. What’s interesting is that almost anything can be used – soil, sand, pebbles, crushed stone.
Further landscaping is also possible, but, as you understand, this is possible with the use of almost any material to strengthen slopes and slopes.
Assignment of sizes
Having dealt with the construction part, the question arises of how to make a retaining wall.
If geological surveys have not been carried out on the slope, designing a retaining wall is possible only if the following conditions are met:
- The height of the earth support on the slope (H) is no more than 1.4 m;
- The depth of soil freezing is no more than 1.5 m.
- The presence of stable, non-porous soils at the base;
- Groundwater level - no higher than -1500 mm;
If all the points converge, you can begin to assign the dimensions of a thin corner-type wall:
Foundation slab depth:
- For walls up to 3.6 m high - 600 mm;
- Height up to 6.3 m - 900 mm;
- At the top - 1200 mm.
The width of the foundation slab is selected according to the tables or within the range (0.6-0.9) H:
Protrusion of the foundation slab onto the front surface of the façade slab:
- For walls up to 3.6 m high - 300 mm;
- Up to 6.3 m - 600 mm;
- Top - 900 mm;
Base plate thickness 200-600 mm;
The thickness of the front panel is at least 100 mm.
For massive walls:
- The depth and width of the foundation are identical to a foundation with thin walls;
- The thickness of the walls depends on the material. So, when choosing a stone wall, the required thickness will be 600 mm, of concrete - 400 mm;
However, to approve the specified dimensions of a retaining wall, it is still advisable to carry out verification calculations, otherwise the wall may not withstand the pressure of the earth and topple. To check the stability of the soil under the sole, use the formulas specified in paragraphs 5.1.17 - 5.1.19 SP43.13330.2012, and to calculate deformations - section 5.6 SP22.13330.2012.
We strengthen the slopes with gabions
We have already talked about this topic, and also studied gabions in detail in other articles. We never cease to be amazed at the possibilities of simple metal structures filled with various materials inside. They are assembled quite simply, and can even be made independently in a summer cottage.
Regardless of the slope, gabion structures become reliable reinforcements. Only the initial condition of the problem area, as well as its height, plays a role. The larger it is, the more difficult the task ahead, but if we are not talking about mountains, but a simple dacha terrain, then any problem is reduced to nothing by gabion structures.
You can install gabions vertically or lay them at the desired angle. But it is worth remembering that they have sufficient weight not only to restrain collapsing plumbs, but also to independently slide along the surface at an angle. Therefore, it is worth reliably strengthening each structure, creating a support in the form of a foundation under the lowest one.
At large slope angles
All of the methods listed below are more labor-intensive, and some require certain financial costs. They are used in cases where the steepness of the site is significant, or planting plants (even with a slight slope) is impractical (or undesirable, impossible) for some reason.
General remarks
- All artificial elements that are used to strengthen the soil must be securely fixed in the ground, otherwise such work loses all meaning.
- The design of the protection may be different, but it is necessary to focus not only on the service life of the materials, but also on the maintainability of this artificial structure. Therefore, you should not blindly copy the slope strengthening technique from your neighbors or friends. Helpful advice is a good thing, but all areas have their own characteristics. This is what needs to be taken into account first of all.
Support walls
For their arrangement, you can use various materials - boulders; reinforced concrete slabs; logs, pipes or channels (in the form of a palisade or with an interval and a mesh installed between the supports). If the meaning is clear, then selecting appropriate samples is not difficult. The pictures show some options.
To prevent the soil from being washed away by liquid streams during intense precipitation, it is advisable to place trays at the top that will collect and redirect water to the drainage system. Here is one of the example diagrams.
Reinforcement with geotextiles
Advantages:
- The material is elastic, so it is easy to install (read more about the characteristics of geotextiles).
- Serves as a good protection for the root system of vegetation from low temperatures.
- Eliminates mixing of soil layers when the area is flooded.
Gabions
They are lattice mats that are filled with various materials - stone, crushed stone, broken bricks, construction waste, and the like. These designs are described very well and in detail here.
Volumetric geogrids
Such products have been on the market relatively recently, but have already proven their effectiveness. They resemble gabions, only they are made not of threads, but of tapes (polymer). This design feature allows the use of geogrids for filling with more massive fractions.
Rock garden
If it is properly equipped, it can serve not only as a garden decoration, but also as a reliable protection of the soil from displacement. Detailed instructions for setting up a rock garden are available on our website.
Other options for strengthening slopes, slopes and banks
Often the situation itself dictates to us the choice of materials for work and the solution to the problem. The reasons may be money, time, available materials, the condition of the site, its height, distance from buildings, bodies of water, or the need to combine complex work and decoration. Therefore, it is necessary to have many options at hand, by assessing the features of which it will be possible to determine the most suitable one:
There are many more methods, but today we have described the most popular and used ones. Therefore, take them into service.
Such work with relief is considered complex and therefore requires a serious approach. We recommend drawing up a work plan in advance and making accurate calculations, making sure to select only high-quality and appropriate materials for the soil strengthening process.
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Variety of materials in design
A variety of materials are used to stabilize slopes, many of which have been in use for a long time and help create a traditional landscape. The choice of material depends on the characteristics of the site, the configuration of the wall and the tastes of the owners. Most often, the following materials are chosen for retaining walls:
- Rock. A practical material in many respects: it is durable and natural, thanks to which it forms reliable protection and adapts to any environment. The stone wall looks respectable, but it takes skill from the performer to put all the stones together. Due to the heavy weight of the structure, a solid foundation will be required.
Design of steps and lighting
Brick. The wall is clean and expressive. Brickwork usually becomes an addition to the residential building itself, so it is advisable to choose the material for it in the color of the main house. The brick can be clinker or solid, but it must be laid with offset rows to strengthen the structure.
Masonry retaining wall
Types of retaining walls
In industrial construction and agriculture, a retaining wall is considered as an engineering structure; in the landscape of a suburban area, it also performs an aesthetic function. Classification of wall types is carried out according to several criteria.
By purpose
Depending on the purpose, the following three types are distinguished:
The peculiarity of a private house with a plot on a slope is that the retaining wall quite often performs all functions at the same time. Therefore, the material for the structure is selected based on the load, operating conditions and decorative qualities. But in this case some contradiction arises.
Based on materials
As a rule, high load-bearing capacity and aesthetic appearance are difficult to combine in one design. Especially when it serves as one of the central elements of the landscape. A compromise has to be found, and when the calculated wall height is quite high, it is better to make a cascade of several low terraces with supporting walls made of a material that more closely matches the style of landscape design.
There are the following types of materials:
By type of design
The following design options for retaining walls are distinguished:
Fence - retaining wall in one
By way of ensuring sustainability
A retaining wall consists of an underground part (foundation) and an above-ground part. The following forces act on it:
The first three forces ensure the stability of the structure, the last one tends to move the wall and overturn it.
According to the method of achieving stability, the following design options are distinguished:
Features of design development
Since walls are engineering structures, certain rules must be followed when designing them, which relate to the following categories:
- Fund;
- Dimensions and proportions;
- Auxiliary elements.
Decorative stone stand to support the soil
Regardless of the type of walls, they must have a foundation. This is necessary, first of all, to create a solid foundation that prevents self-destruction of the walls under the influence of a combination of factors. In addition, the foundation will additionally hold the soil.
Retaining wall made of block sections in a strict and consistent landscape style
Important: the foundation cannot be installed only if the wall is purely decorative in nature and is used to create geoplasticity - artificial correction of the even terrain of the site.
Hay storage is designed to prevent soil movement
If the foundation is not equipped, it is necessary to create a wall structure containing a fertile layer of soil instead, especially if multi-level terracing is involved. In this case, not a separate foundation will be created, but a deeper part of the wall, expanded at the base. It will perform the same function. In this case, it will be necessary to deepen the wall by at least a third of its height, respectively, at a height of 90 cm, the underground part will be 30 cm. The width of the lower part should be twice as large as the upper one.
Concrete wall with small foundation
The walls must have drainage elements. If desired, you can also add lighting elements to the design that will illuminate the area at dusk.
Landscaping of the surrounding area with good lighting
Construction of a retaining wall
Below is a general algorithm for constructing walls from different materials.
Made from monolithic reinforced concrete
The step-by-step construction algorithm looks like this:
After the concrete has matured, the formwork is removed and soil is backfilled into the grooves of the trench and behind the wall on the slope side.
Precast concrete
The construction technology depends on the type of concrete blocks. If foundation blocks are used, they are laid on a prepared base in the form of a sand and gravel cushion.
Blocks of the FBS series are fastened together with masonry mortar, and blocks of the BPS series are mounted dry.
In addition to foundation blocks, there are other materials that allow you to quickly and without “wet” processes build a retaining wall from precast concrete.
A very interesting product is offered by Geoblok and Tenax. They developed a system of block retaining walls reinforced with geogrid. It includes:
The retaining wall manufacturing technology looks like this:
The blocks are produced painted in bulk, but, if desired, they can be faced with any tile for outdoor use - the rough surface of the front part ensures good adhesion to adhesive solutions. According to the company, the system of reinforced primed block retaining walls is designed for 120 years of operation.
From stone and building blocks
Despite the variety of types of building blocks and sizes of stone, the construction technology in each case has a similar sequence of work:
Made of wood
Arranging a retaining wall made of wood is somewhat reminiscent of a fence (wall) made of logs or large-section lumber. It could be:
Finally. The construction of a retaining wall from gabions is no different from other landscaping and reinforcing structures using wire mesh and backfilling with fragments of rock soil, large crushed stone or pebbles. A retaining wall made of corrugated sheets follows the same algorithm as the construction of a fence (taking into account the loads on load-bearing pillars or screw piles).
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DIY retaining wall
A retaining stone wall, the height of which is 1 meter, with longitudinal drainage.
1) You need to mark the area.
A suitable place for support is selected in advance (with a slope near the terrace, which is located higher than ground level). Along the edges of the selected area, stakes are driven in and a cord is pulled.
2) Prepare the trench.
Using a garden knife, cut through the soil according to the markings. And with the help of a shovel, a thin layer of soil is removed. This will be followed by digging the trench itself, the depth of which will be 40 cm.
3) Laying the foundation.
The bottom of the trench is thoroughly leveled and compacted. Then a layer of concrete is poured to a depth of at least 30 cm. The concrete mixture for the foundation consists of one part concrete, 6 parts sand and gravel. This should be the proportion.
If the soil is loose, then before pouring the concrete mixture, you should make a wooden fence. Allow the concrete pad to dry completely, which will take about three days.
4) Creation of a lime layer.
When the foundation is completely dry, before laying the stone, you need to smear it with a lime mixture in layers of 2-3 cm. The mixture contains sand, water, cement and lime. For one part of quicklime you need 3-4 parts of sand. For each kilogram of such a mixture, 300 ml of water is required. To avoid lumps, water is added gradually. Then you can add cement. We get the ratio: 1 part cement to 7 parts mixture.
5) Lay the stone.
The stones are carefully cleaned of dirt and moistened with water. You cannot place stones one on top of another. Otherwise, the building will collapse due to the slightest external influence. The junction of two stones is located in the center of the stone located in the previous row. A larger stone with regular shapes is always placed along the edge. A smaller stone is suitable for the middle. We must try to find stable positions for all the stones.
For the next row of the wall, the same principle is used using lime mortar. The mixture should have a minimum thickness of 1-1.5 cm, otherwise too large seams will be quickly destroyed. For stability and strength of the structure, the edge at the back is made with a slight slope towards the retained soil (approximately 5-10 degrees).
Laying stone
The broken curved configuration of a retaining wall is more durable and reliable, since such wall lines are characterized by a reduced span length. There is no huge load on them, and thanks to the rough surface of the back wall, there is more intimate contact with the soil.
6) Use of drainage and drainage.
Each installed row of support between the soil and the wall requires a layer of crushed stone with gravel or small pebbles with gravel. After this, everything is carefully compacted. When you lay the second row of support, you will need a drainage pipe.
Once the retaining wall is installed, traces of lime mortar are removed with water, a sponge and a brush.
Industrial methods
When constructing large, critical facilities in difficult conditions, soil strengthening is used using the following measures:
The choice of method depends on the conditions of the specific site where construction is taking place: the type of object, its purpose, size and number of floors, slope, groundwater level, type and characteristics of soil. Before carrying out measures to strengthen the slopes on the site, engineering-geological, engineering-hydrological, and geodetic surveys are carried out to determine all the factors influencing the choice of one method or another.
Important! Strengthening the slope against sliding is carried out on the basis of the requirements of SNiP 22-02-2003 “Engineering protection of territories, buildings and structures from hazardous geological processes”, SP 45.13330.2012 “Earth structures, foundations and foundations” and other regulatory documents in force in the Russian Federation.
Changing the profile of an existing terrain
The profile of the existing relief is changed in several ways: terracing, removal of unstable soil and its replacement, installation of a special persistent counter-bank in the lower zone of the slope that prevents soil sliding.
With the help of terracing, the steepness of the slope is reduced and it is given a more stable shape. Terraces are usually installed at the boundaries of soil layers with different characteristics and in areas where groundwater seeps to the surface. The width of the terraces and the height of the differences between them are determined by calculation. The installation of terraces is accompanied by a set of measures for drainage.
Removal and replacement of unstable soil is carried out in cases where all other methods of securing slopes are considered impractical and economically ineffective.
The installation of a counter-banquet is carried out on the basis of preliminary calculations, which determine the size and shape of the abutment structure made of soil, the density of its laying and the drainage pattern of surface water.
1 - slope surface; 2 - counter-banquet; 3 - sliding surface; 4 - numbers of calculation compartments into which the landslide massif is conventionally divided.
Regulation of the hydrogeological situation
Regulation of the hydrogeological situation includes the following activities:
In order to regulate the movement of surface water, vertical planning of the terrain at the construction site is carried out, special drainage systems and storm sewers are installed to remove water outside the construction area.
To prevent water seepage deep into the soil mass, it is necessary to carefully monitor possible leaks from industrial and domestic water supply systems located near dangerous slopes and eliminate them in a timely manner. Also, for these purposes, such phenomena as the accumulation of rain and melt water in pits and trenches during construction should be excluded.
Lowering the existing groundwater level is carried out using the following measures:
Agroforestry
Strengthening slopes using agroforestry involves planting trees and shrubs, the branched root system of which, like the reinforcement of reinforced concrete structures, helps strengthen the soil on the slope. Planting trees and shrubs is also combined with sowing perennial grasses, which stabilize the top layer of soil. Agroforestry is allowed to strengthen slopes up to 35° steep; the selection of tree and shrub species is carried out taking into account the climatic conditions of the construction region.
Improving the strength properties of soils
Soil strengthening is a method that involves introducing special agents into the natural soil mass that change its properties and improve the characteristics of strength and stability. Soil strengthening is carried out using the following methods: cementation, bituminization, silicatization, resinization, electrochemical and thermal consolidation.
Cementation involves the process of injecting an aqueous cement solution into the soil mass through special injector wells. As a result, the cement mortar penetrates into the pores of the soil mass and, upon subsequent hardening, contributes to a significant increase in the strength, stability and waterproofness of the soil. Cementation technology can only be used for coarse soils and sands of medium and coarse fractions.
Methods of bitumenization, silicatization, resinization are carried out according to the same principle of injecting into the soil mass a liquid substance of molten bitumen or cold bitumen emulsion, liquid glass, synthetic resin, which also penetrate into the pores of the soil, increasing its strength properties after hardening.
The method of thermochemical consolidation consists in immersing hollow electrodes - anodes and cathodes - into the soil mass in a certain order, and passing a direct electric current through them. In this case, the water located in the pores of the soil begins to move towards the cathodes and is pumped out through them. And through the anodes, special salt solutions or liquid glass are pumped into the soil, saturating the soil and promoting the formation of denser and stronger structures. It is used to strengthen sandy, silty and clayey soils.
The thermal method involves burning soil under high temperature. Roasting is carried out by injection of hot air into drilled wells or by burning petroleum products in them. As a result, structural changes occur in the bonds between soil particles, increasing its strength and stability. Used to strengthen clayey and loess soils with high porosity and subsidence.
Arrangement of retaining structures
To prevent landslide phenomena, the following retaining structures and materials are used:
Retaining walls
Retaining walls are used to hold layers of soil of a certain thickness with installed sliding surfaces along which soil masses can slide. Retaining walls can be built from various materials - stone or brick, rubble concrete, concrete and reinforced concrete, small-sized blocks. The design and configuration of retaining walls are determined by the project. When constructing them, it is important that the foundation of the structure is located in a layer of stable soil.
In difficult cases, when it is necessary to construct a protective barrier to a depth of more than 4 meters, the “wall in the ground” method is used. Using earthmoving equipment, soil is removed to a great depth and the cavities are filled with monolithic reinforced concrete, prefabricated concrete products or a mixture of clay soil and cement. A wall in the ground can also be created from bored piles.
Pile structures
In cases where the layer of unstable soil is thick, retaining structures made of piles are used. Typically, bored piles are used, which cut through the soil mass to the required depth. The number, depth of depth, and location of piles are determined by the project. In certain cases, prefabricated piles can be used - reinforced concrete, steel, wood by driving, pressing, vibrating, screwing. In each case, the danger of the dynamic impact of the immersion method on the stability of the soil mass and on nearby buildings or utilities is assessed.
A continuous retaining structure made of piles is called a sheet pile or sheet pile course. Pile structures can be combined with retaining walls.
Larsen sheet piling is often used for the construction of retaining walls (especially for bank protection and strengthening the slopes of pits).
Larsen Sheet Pile Retaining Wall.
Geotextiles, geogrids and geogrids
One of the ways to strengthen slopes is reinforcement using the following materials:
All these materials have high tensile strength, resistance to temperature changes, moisture, aggressive chemicals, and harmful microorganisms.
Strengthening the slope with geogrid.
Strengthening slopes using geopolymer materials is done in a similar way. The canvases are laid on a leveled base of the slope, secured to each other and to the ground using metal anchors, then covered with a layer of crushed stone or gravel, then with a layer of fertile soil. Finally, they are covered with a layer of turf or tiles provided for by the landscaping project. Reinforcement with geopolymer materials can be used for steep slopes with a slope of up to 60-70°, in combination with agroforestry measures, when the roots of planted trees and shrubs penetrate through the canvas and further strengthen the slopes.
Gabions
Gabion structures for strengthening slopes are constructed using a steel mesh with hexagonal cells made of double twisted wire, which gives special strength to the gabions. Rectangular volumes are created from wire, which are filled with small and large stones of hard and durable rocks. Gabions are constructed in places most susceptible to landslides - at elevation changes and at the bottom of slopes.
What affects the stability of retaining walls?
Maximum stability and resistance to high pressure are very important qualities that a well-made retaining wall should have. Otherwise, the structure can easily collapse and the soil can slide. Therefore, it is necessary to take into account every factor on which the strength of retaining walls depends.
So, we need to figure out what actually affects retaining walls? The influence of the building’s own weight, the forces of adhesion and friction with the ground, soil pressure, the additional weight of components that may be on it - all this is of enormous importance.
What can influence the design of the building:
- soil swelling in winter;
- wind force (if the retaining wall is higher than 2 m);
- vibration level (for example, if there is a railway nearby);
- any seismic phenomenon (each region has its own characteristics);
- washing away by rainwater.
An additional factor influencing the level of stability of a building is the thickness of the wall. It is determined by the type of soil and the height of the structure itself. If the ground is soft and the support is high, then it is natural that the width of the protective “shield” should be greater. It's logical.
Traditional methods
Traditional methods are used to strengthen slopes in areas where private residential buildings and dachas are built. In most cases, the same industrial measures are used, only more simplified so that they can be implemented.
Planting shrubs and trees
When strengthening slopes by planting trees and shrubs, it should be borne in mind that in these areas it will be impossible to cultivate garden crops. Therefore, the slopes on which vegetable beds are supposed to be constructed are best strengthened by terracing.
Construction of terraces
On a slope intended for growing vegetables, it is enough to cut terraces 1.5-2 m wide, which is enough to create beds. Moreover, the steeper the slope, the narrower the terraces will have to be made. The optimal height difference is 500-600 mm; the ledges can be reinforced with wooden boards, placed on stakes driven into the ground, or retaining walls can be built from stone, logs and other available materials.
Retaining walls
Retaining walls intended to strengthen terraces or constructed in places of large differences in the landscape of the site are best built from natural stone - slate, limestone, sandstone, etc. – dry method, that is, without the use of cement mortar. Seeds of perennial plants can be planted in the seams between the stones, which will later add a special flavor to the landscape of the site.
Geopolymer materials
To reinforce the soil on the slopes of a summer cottage, it is quite possible to use geotextiles, meshes, mats, geogrids, since strengthening slopes with the help of geopolymer materials does not present any difficulties even for non-professionals. These activities are best carried out in combination with other methods - terracing, installing retaining walls and planting trees and shrubs.
Measures for drainage of surface water
Great attention should be paid to the drainage of surface water from the site, since under the influence of water, erosion of slopes most often occurs. To drain surface water, all methods of constructing drainage structures are used - trenches, pipe drainage, trays, with the help of which rain and melt water are drained outside the site.
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Source
Surface version of the construction features
To determine which surface drainage method at the dacha will allow you to get rid of dirt on the site, you must:
Analyze the number of places where water accumulates after heavy rain - perhaps it is enough to make just a few drainage points.
Determine the direction of natural flows so as not to make a mistake with the trajectory of the ditches.
Find a place where you can drain excess water. If there is no pond nearby, a drainage ditch between plots or a deep ditch, you will have to equip a drainage receiver.
Surface channels on the site
Types of surface drainage systems
With your own hands, it is advisable to equip only surface dacha drainage of a point or linear type - these systems do not require the use of equipment, and you can plan the locations for laying ditches yourself:
Point outlet. A system for local collection of excess moisture is the installation of receivers or arrangement of drainage ditches directly in places where liquid accumulates: in recesses, under drainage pipes, in the lowest places of the site, points of height difference. Several rainwater collection points can solve the problem if the main area does not flood after rain.
Linear system. This method involves covering the entire area of the summer cottage with a system of connected trenches to drain liquid. The linear scheme is implemented with the construction of a closed or open trench system. The advantage of this method is uniform drainage of the soil throughout the entire area.
Installation of a linear drainage system in the garden
Open system for removing moisture from the ground
The easiest and cheapest way to make drainage in a summer cottage is to equip an open linear surface drainage system. Drainage ditches are dug at an angle to a relatively small depth - up to 50 - 70 cm. The width of the trenches varies: from the narrowest at the beginning of the branch, to widening by several tens of centimeters in the direction from the beginning of the ditch to the connecting highway. The greatest width is dug at the drainage site. The walls of the trenches are formed at an angle to the bottom - the angle of inclination should be up to 30 - 35 degrees.
To strengthen the walls use:
Remains of building materials: slate, brick, concrete slabs.
Reinforced with slate sheets to prevent walls from collapsing
Perforated textiles – agro- and geotextiles. Special material that does not rot. Plants grow through small holes, which with their root system are able to strengthen the soil on the walls and protect the ditch from crumbling.
Gutter protection with soft material
Concrete gutters, metal mesh, stone laid on the mortar.
Gutter lined with river stones: this gutter is easy to clean
How to make the most economical drainage in your dacha? Leave the channels completely open, filling them with crushed stone, gravel or a mixed gravel-sand mixture. This budget solution is perfect for areas where problems with soil erosion occur infrequently.
Surface drainage groove with backfill
There are many design options for open channels: ready-made trays made of plastic, metal, concrete with decorative gratings.
Closed drainage network
It is much more difficult to make closed drainage on a summer cottage without the involvement of specialists. A closed system is a network of perforated pipes laid with mandatory observance of technology and slope along the entire perimeter of the site.
Closed system diagram
To carry out the work, it is necessary to accurately plan the installation locations of the pipes - in case of an error, the entire branch will have to be redone. Therefore, craftsmen use laser rangefinders and special equipment to calculate with millimeter accuracy the required depth and slope of the pipeline.
Execution of work: selection of installation direction
Before installing the perforated pipes, the dug trenches are strengthened and a gravel bed is created. Textiles must be installed under the backfill. For different sections of the system, pipes of different diameters are selected.
Installation of perforated pipeline
In addition to the costs of pipes and excavation work, it is necessary to calculate the number of inspection tanks. Perforated pipes will have to be washed, and in order to get to the junction, wells with access to the surface are installed along the main line.
Wells are an essential part of a closed system
The advantage of a closed discharge system is absolute invisibility. The pipes are dug into the ground, and after the work is completed, there are no open ditches left on the surface. It is advisable to install closed drainage during the construction of a house. On a summer cottage, which is used only for seasonal growing of vegetables, it is enough to make a simple, economical open system.
