Boiler House Foundation and Foundation Design

Contents

1. Analysis of the initial data on the above-foundation structure

2. Analysis of engineering-geological and hydrogeological conditions of the construction site

3. Determination of foundation depth

By purpose and structural features of the designed structure

By depth of foundations of adjacent structures

On loads and impacts on foundations and foundations of engineering and geological conditions of the construction site

On the existing and projected terrain of the built-up area

By depth of soil freezing

According to hydrogeological conditions during construction and operation of the facility

4. Selection of Base and Foundation Types Based on Case Comparison

Determination of preliminary dimensions of foundation bottom of shallow foundation by graphical method

Determination of preliminary dimensions of deep foundations

5. Construction of foundations. Protection of premises from groundwater and damp

6. Calculation of bases by limit states

7. Literature

4. Selection of Base and Foundation Types Based on Case Comparison

Selection of types of bases and foundations is carried out on the basis of joint analysis of initial data on engineering-geological and hydrogeological conditions of the construction site and above-foundation structures.

In most cases, soils are used in a natural state. But if the upper, relatively small thickness is composed of weak soils that are not able to perceive the load from the foundation in a natural state, then the following measures are provided (compaction, fixation or replacement with other soils with the necessary properties). If the thickness of weak soils is large, then measures to artificially improve them or replace them can be provided by a foundation method, in which the load is transferred to dense layers lying at a significant depth under the thickness of weak soils.

For this purpose, pile foundations (for example, piles, piles - shells, piles and pillars) are arranged.

It is necessary to consider two options of foundations (shallow or deep laying), and choose from them the most suitable.

The foundations of the shallow foundation include finishing (columnar), tape or in the form of a continuous railway plate.

Types of piles are distinguished by material, cross-sectional or longitudinal shape, manufacturing method and soil immersion. At the same time, penetration by piles of clay soils of hard and semi-solid structure is allowed in exceptional cases. Piles cannot be used when there are boulders.

4.2 Determination of preliminary dimensions of deep foundations.

We are developing the following option:

- pile foundation with low pedestal at vertical piles.

The elevation of the sole of the solution is applied to the geological section. Analysis of geotechnical conditions allows you to conclude about the type of piles. If there are practically incompressible rocks in the soil massif (rock, half-rock, large-breaking and clay soils of hard consistency, then piles are used - posts, otherwise - hanging piles (friction piles)).

The bearing capacity of the hanging pile is composed of the resistance of the soil under the tip and the friction forces of the soil along the side surface, therefore, the pile point must be located in stronger soil when buried in it by 2-3 m. Soil strength qualitatively characterizes the value of the conditional design resistance of the soil Ro. Thus, the pile length in the first approximation is obtained.

If within the length of the submerged part of the pile there is a layer of strongly pressed (weak) soils (peat or thickness more than 30 cm), then the friction forces in this section of the pile length are considered to be equal to zero. The friction forces of the soil located above the strongly pressed layer are considered negative (negative) and they should then be added to the load from the building acting on the pile.

The type of hanging pile is chosen: driven or stuffed with different structures, shell piles (with a diameter of more than 800 mm), piles - poles. For example, if a pile cuts through a powerful thickness of strongly compressed soils and its lower end in dense (strong) soil, then it is most advisable to accept

bored pile with widening within the limits of strength soil. In this case, the strength of the pile concrete is used as much as possible. Driven and bored piles without widening are used with sufficiently homogeneous layers of soils in terms of strength. Dimensions of driven piles and piles - shells are accepted according to GOST and padded depending on technical parameters of equipment. The mating of the pile pile with the piles can be both freely resting and rigid. The free opiraniye is considered, be quits as hinged and the grillage on 5 - 10 cm is structurally carried out by seal of the head of a pile monolithic. Tough interface of a pile to a grillage is carried out by seal of the head of a pile in a monolithic grillage on depth corresponding to length of anchoring of fittings or seal in a grillage of releases of fittings.

The bearing layer against which the pile rests must be with a maximum value of Ro and it must be located at a depth of not more than 12 m from the sole of the pile cap. Deepening of the pile into the bearing layer must be not less than 1 m into clay soils and 0.5 m into sandy soils. After selecting the pile length from the catalog, select the desired pile and define its parameters.

5. Construction of foundations. Protection of premises from groundwater and damp.

The foundations of buildings, as a rule, are concrete and reinforced concrete, therefore they are designed on the basis of SNiP according to concrete and reinforced concrete structures .

For prefabricated foundations, separate typical elements will be used, for example, foundation slabs, wall blocks, sub-column parts of foundations. Ordinary foundations for columns, foundations for spacer structures.

The dimensions of the upper stage in plan (cut) for the metal column are taken taking into account the placement of the metal shoe for sealing anchor bolts. Distance from anchor bolt axis to vertical face of upper stage of foundation is taken not less than 150 mm and at diameter of bolts 50 mm and 200 mm at diameter of bolts more than 50 mm.

When using prefabricated unified foundation elements, they are not designed, but you need to specify the element or foundation mark and GOST number or typical series.

When applying monolithic foundation, formwork drawing.

For pile foundations, the type of pile sealing in the pile pile. The construction of the seal depends on the type of piles.

Under monolithic foundations, regardless of the underlying soils (except for rock), concrete preparation with a thickness of 100 m from M50 concrete is provided. For prefabricated foundations, instead of preparing from concrete, sand filling with a thickness of 100 mm can be used.

Measures to protect rooms from groundwater and damp are aimed at protecting buried parts of the building, from damp and flooding with groundwater, from corrosion and destruction of structural materials. The choice of these measures depends on the hydrogeological conditions, the peculiarities of the structures and the characteristics of the premises.

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