One of the difficult tasks faced by the owners of country houses and suburban areas - construction of a fence in a moist soils exposed the so-called frost heaving.This often becomes a real problem: the cold saturated with moisture in the soil expands and pushes upward hammered support and drenched foundations.The power of nature "jack" is sometimes that the steel trapezoidal sheet is torn like paper and brick fences on capital foundations are cracked.
soils, more or less susceptible to frost heaving, are found in many regions, so that users FORUMHOUSE accumulated considerable experience dealing with this enemy of fences and foundations.Let's try to summarize it and to understand the advantages and disadvantages of different options of construction of the fence on heaving soils.
- If the ground puchit, no dead weight of the fence can not prevent this.Even small diameters of the pillars will not help, since the shear stresses in the frost heaving will still mangle it.
Experienced Gameday warn universal solutions, alas, does not exist.Thoughtlessly using other people's good example or advice "seasoned", the owner of a new fence may be in the first winter get a nasty surprise in the form of a raise or lop-sided pillars.Therefore, the construction of the fence should be started only after you have decided on the type of soil, and to calculate the possible risks.Do not interfere, and information on how to behave in the previously constructed fences neighbors.But one needs to be careful: the parameters affecting the degree of heaving soils can vary even in the surrounding areas.
for self-determination of the degree heaving need to know the depth of the groundwater level (GWL) and the depth of soil freezing.GWL is subtracted from the depth of freezing and the ground water level get below the freezing depth (Z value in the table).Compare with the tabulated value in the column of your soil.For example, 1.2 m in the obtained clayey soil - component Z & lt; 1,5, i.e. ground silnopuchinisty high relative deformation & gt; 0,07 (7%).Columns in this ground, if not installed can lift more than a dozen centimeters each winter.
The calculations should use the pre-winter groundwater levels (measured not earlier than August), but for reassurance heaving better determined by the maximum seasonal groundwater table, advises forumchanin al185 .It should also be understood that a separate calculation is approximate and that not much mistaken, come from the "worst" performance.
One common option to control frost heaving - deepening of the pillars of the fence below the freezing depth.Thus, on the heel post below is not to press the frozen expanding ground.
But fundamentally it does not solve the problem: the seasonal freezing of soil heaving significant lateral forces that put pressure on the pole at a tangent.A simple case of concreting also not help, it will only increase the area of application of forces and a post will be squeezed out with concrete "skirt". To reduce the tangential swelling, some forum users concreted poles, placing them in the pocket of tar paper or plastic pipes.Under the heel post poured drainage bed of gravel, which should always be below the freezing depth.Here's how the user entered offline welser:
- At 0.25 meters in diameter hole put a shirt of roofing material, poured into 1.5 buckets of gravel, put a post (70-ka, shaped tubes), filled with concreteto the edge of Ruberoid shirt.Everything costs, no swelling.
Many, however, believe the pouring of concrete, even deeply buried pillars on heaving soils unnecessarily risky and costly and time consuming option.And prefer instead to backfill pillars unaffected by heave materials - sand and gravel, gravel, coarse sand.
- digging holes on 1,5metra, to the pillars - and gravel mixed with sand rammed.Before the fence was a concreted pillars wave.New fence winter and is survived after thawing of soil, as a string.The soils have a very distending.
When backfilling forum users are also often used in roofing liners and geotextile-for insulation backfill from the ground.The best option, according to the user SidorD , if between the sleeve and the wall of the hole is the same sand and gravel layer.
- Over time, any smooth surface silted up and still comes into contact with the ground.The layer of material nepuchinistyh solve the problem, it does not give ground when heaving pull a pole: bulk materials in a low adhesion between the layers, ie. E. At the edges of the sleeve ground rises, and in the center, where there is a post, remains in place.
Plus this method in the fact that if due to incorrect calculations of the fence all the same "lead" to correct the situation will be easier than in the case of concrete pillars.However, many people confuse that no concrete fence can turn out not too stable.Experience of members of the forum shows that quality, layer by layer, with pouring some water, tamping backfill mixture of sand and gravel around the post provides a monolithic mass without cavities, and post it will hold firmly.Again, a little rickety support can be in a few minutes to fix and strengthen with a crowbar and a bucket of gravel.
user Groundworkturf advises to minimize wind loads zabutovany strengthen further concrete pillars "hats".
- Before drilling the holes for the pillars dig a square pit 0,4h0,4 m depth of 30 cm (to clay loam), and then the center of the hole for the post;install it, butite gravel to loam.Square pit was covered with geotextile and filled with rubble from the same rammer 20 cm. You set the formwork along the perimeter of the pit and pour the slab 15 cm in height.
less popular due to more expensive and time consuming way - to use as poles screw piles with bladesat the end of performing the function of the anchor.Screw piles also need to move deep below the frost line, or in the winter they also can "squeeze."
above methods are good for relatively light fences, for example, corrugated sheet or wood.However, embodiments with a deep pillars below the freezing depth of soil are suitable, of course, not all and not always.In some regions, the freezing depth can reach up to two meters - drilled out long and troublesome.
You may want to consider the option of construction of the fence on the unburied supports.For example, robust but, alas, labor-intensive and expensive way - the construction of a belt or a combination of foundation designed to cushion nepuchinistyh of materials, reinforcement and blind area to protect them from rain and melt water.
- Make excavation of clay to the width of twice the ribbon foundation.Bed geotextile flare and make dumping the rammer 10 cm and 30 cm sand gravel.Then cast tape racks installed fence.
user al185 found that its soil srednepuchinistogo practical to build a fence on the unburied supports (concrete soles) with additional insulation.According to him, dug in between heaving soils post and sole have a fundamental difference: every year outsole sits down and bulging pillar accumulates each year.Warming is particularly important on the pillars of the gate - this site is cleared of snow in winter, and therefore less protected from freezing.
to manufacture soles by linear fence posts forumchanin leveled basis put on the formwork board of 100 mm.It installed plumb pipe on the legs.Poured concrete layer of 3 cm, was putting several cross rods of 4 mm and topped up with concrete top.
- Under the gate is filled w / w platform 4h1h0,1m with asbestos cement pipes, surrounded by fieldstone.Under it - 100 mm foam PSB-25.Fence posts of asbestos cement pipe embedded in the sole of rhombic 1h0,5h0,1m, buried 15 cm. The sense of the foam under the linear columns do not see under the snow heave does not exceed 1-2 cm. Sam fence - horizontal boards 25h150 overlap.80 m fence defended two winters and two springs with squalls.Fences neighbors on stone pedestals curves.
If the incorrect calculations or wrongly chosen technology led fence yet, you can try to solve the problem of insulation of the foundation or supports, according to the user Val7676.According to him, it will be cheaper and easier entrenchment of each fence post and replace the soil around it on nepuchinisty.
- from the fence near where nobody goes and cleans the snow, there is almost no problems.Events on warming - compensator lack of snow in the Gates (ie, where it is not), in order to align it with the freezing of the soil columns located under the snow.Thus the pillars can be erected and backfill and concrete, and other methods.
experience in the construction and installation of poles and foundations for various types of fences divided Gameday in this section. here and here - to discuss options for the construction of the fence on the heaving soils and how to combat frost heaving.On the experience of building the foundations on swampy soils covered in this video.