Build Daily

August 12, 2017 18:06

The foundation of quicksand on its hands

One of the most difficult situations for the construction of the building is the presence in the ground quicksand - a mixture of soil and water particles.Quicksand typically localized at a particular depth, if it is not damaged, it is quite stable.However, when you try to build a buried foundation quicksand builders can deliver a lot of trouble.

The foundation on quicksand

foundation on quicksand

How to build a foundation on quicksand?There are several ways, and the choice depends on the location and depth of placement of the unstable soil layer.Therefore, before you stop the choice on any method, it is necessary to order a geological study of the site for construction.In the study you must identify:

  • depth of soil freezing (PIP);
  • groundwater level (GWL);
  • depth of occurrence of quicksand and the thickness of its layer.

methods of combating quicksand and the choice of the type of foundation

Fight quicksand is possible only in one case - if it is possible arrangement of the drainage system below the level of its occur

rence.Quicksand is a suspension of fine dust particles of sand with clay impurities in the water and has a semi-liquid consistency of the high viscosity.Qualitative drain with tap water can dry quicksand and prevent its further occurrence.In the process of use of the building would have to conduct regular audit of the drainage system.

Ways to combat quicksand

methods of combating

quicksand quicksand is not itself dangerous, if not damaging its integrity.Therefore, if the dry quicksand is not possible, you must choose a method of construction of the foundation, which will avoid contact with the foundation of quicksand, or will bring the contact to a minimum.

If the geological studies of soil it was found that quicksand is at a considerable depth below the depth of soil freezing, to a private house, you can choose a monolithic strip foundations shallow gravel bedding, or if the size and weight of the buildings are significant, slab foundation on gravel-peschanoy preparation.

When quicksand is located at a depth of no more than 0.5 meters and its thickness is negligible, and beneath it are solid and stable ground, it is better to opt for a pile foundation with the raft of concrete or using screw piles.Piles bury in solid layers of soil at least 1 meter, perform thickening basis, preventing expulsion of the forces of frost heaving piles.

Melkozaglublenny strip foundation on quicksand

This foundation is carried out at occurrence of quicksand at a depth of not less than 1.5 meters on slabopuchinistyh soils.If you want to equip built his cellar by lifting the cap on the ground, not buried underground part of the foundation.

  1. Site preparation is reduced to site clearance, leveling, digging a shallow pit and arrangement of horizontal drainage.In the case of raising the level of ground water drainage will prevent capillary rise of moisture.Pit depth - from 0.5 to 0.7 meters.The bottom of the pit is filled with gravel, crushed stone on top - coarse sand.Carefully ram podsypku, spilling its water.
  2. Perform formwork made of boards or panels at the height of the basement foundation.The formwork is laid plastic sheeting or other waterproofing material to prevent leakage of concrete during concrete pouring milk, and then carry out reinforcement of the foundation in accordance with the calculation.
  3. Pour concrete formwork M200 or higher grade, remove air bubbles from concrete with a vibrator and level the surface.Maturation of concrete last for at least 28 days, at this time, the foundation must be protected from rain and direct sunlight.
  4. After drying concrete foundation waterproofing is necessary to perform, if necessary, its insulation, then produce backfill sand pit.
A sample of the construction of the foundation

foundation erection Sample

slab foundation on quicksand

applied in the case of deep-seated quicksand on heaving and moist soils.Called floating slab foundation - its designed to withstand a considerable load of the building, and when frost heaving and shifting of soil foundation is shifted together with the entire building, without strain.

  1. leveling pad and perform podsypku gravel with sand to a height of 0.5 meters.Firmly tamp it, spilling the water.Produce markup.Stack underground utilities.
  2. Produce horizontal hydro and thermal insulation of the base slab foundation: placed on a prepared podsypku layer of expanded polystyrene insulation and waterproofing roll on it.
  3. Formwork slab foundation is made of boards or plywood boards, shuttering height - about half a meter.Prepared surface veiled polyethylene film strips prokleivaya joints with duct tape.The film prevents the flow of concrete and the concrete formwork from milk, in addition, it provides mobility in the case of slabs of ground movements.
  4. Perform reinforcement using grooved rods 12-16 mm in diameter, putting its net increments of 15-20 cm. At the intersection of bar knit with wire.To fittings were completely sunk in concrete, it is necessary to lay on the plastic rod guides.
  5. Concrete is poured into the prepared formwork, leveled and compacted it using vibrators and vibrating beams, smooth regulation.Dries concrete 4 weeks, at this time it must be protected from precipitation.
The sample is poured foundation

Sample flooded basement

pile foundation on quicksand

Such foundations operate in the event that quicksand is located in close proximity to the surface of the soil, but its depth is low and stable solid soil layers located below.This situation is typical for wet silty loams, where shallow groundwater is located.They feed off of quicksand, and drainage device is not sufficient for the drainage of the soil.Therefore, the only way to create a stable and secure foundation is the penetration depth of the pile on solid grounds.

  1. Site preparation is reduced to its purification from vegetation, debris and markup.
  2. Piles can be used as concrete and steel screw.The second option is preferable because of the cost, in addition, screw piles can be easily installed without the use of specialized equipment.The advantage of screw piles is the fact that their installation is in conjunction with the drilling, then do not have to take measures against flooding wells and pump water in case of damage quicksand.
  3. piles installed in the corners of the building, at the intersection of walls, as well as every two meters under the load-bearing walls.Screwed metal piles together, with a lever inserted into special ears, checking the level of verticality.Concrete pile hammer with a special technique.

Metal piles screwed up hard soil and continue their penetration least a meter.If necessary, they are increasing.Surplus steel piles cut grinder, and secure the top rail: from metal - welding, timber-framed - with the help of special end walls.

Pile foundations on quicksand

pile foundation on quicksand

Safety

If any excavation in the area with quicksand need to take action against the breakthrough quicksand.In the event of damage to the integrity of the flooding of the excavation can occur in a matter of seconds, and it is very difficult to get out of the viscous mass.

Therefore, when working you must:

  • walls pits strengthen boards;
  • The pit depth of more than a meter to set a ladder that provides rapid rise upward;
  • All work should be carried out a brigade of two or more people.