Soil mechanics, foundations and foundations

Contents

Introduction

1. Geotechnical and hydrogeological conditions of construction site

1.1 Determination of normative values of soil physical state characteristics and complete soil name

1.2 Determination of normative values of physical and mechanical characteristics of soils

2. Shallow Foundation Design

2.1 Purpose of foundation depth (well 2)

2.2 Sizing the Foundation Floor

2.2.1 Assignment of preliminary dimensions of foundation foot

2.2.2 Check of pressure under foundation base

2.3 Calculation for plate part pressing

2.4 Determination of base settlement value

3 Design of pile foundations

3.1 Selection of pile type and pile depth

3.2 Determination of pile bearing capacity

3.3 Determination of number of piles in pile pile, pile pile design

3.4 Checking the load capacity of the busiest pile

3.5 Settlement calculation of pile foundation

3.5.1 Sizing the conditional foundation

3.5.2 Check of pressure under the base of the conditional foundation

3.5.3 Determination of pile foundation settlement

3.5.4 Selection of pile-piercing equipment and determination of pile failure

4 Technical requirements for performance of works

List of sources used

1. Geotechnical and hydrogeological conditions of construction site

To substantiate the design solutions for the foundation arrangement, it is necessary, first of all, to study the engineering and geological conditions of the site.

In the course work there is a base consisting of three different layers of soil. For each layer, you must:

determine design characteristics of soil physical condition;

determine the full name of the soil according to [1];

determine the normative values of strength and deformation properties of soils according to the corresponding tables;

determine design values of physical and mechanical characteristics of soils;

construct a geotechnical section of the construction site.

1.3 Characteristics of the designed building

1.3.1 General provisions

You must install:

- the degree of responsibility of the building;

- functional purpose;

- assess rigidity of above-ground structures ;

- set values of maximum possible deformations for this structure;

- determine design values of loads acting on foundations and bases;

- select the main load-bearing structures of the above-ground part of the building.

1.3.2 Design values of loads acting on foundations

The assignment for the course design gives the normative values ​ ​ of the longitudinal force acting in the plane of the foundation cut (Non = 1400 kN, Qon = 200 kN/m).

In the course design, the values ​ ​ of design loads on the foundations NoI are allowed, NoII accept:

- when calculating bases according to the II group of limit states (by deformations) equal to the normative ones (αf = 1.0);

- at calculation by I group of limit states - equal to standard ones, multiplied by averaged reliability factor by kam load (αf = 1.2).

1.3.3Selection of main load-bearing structures of the above-ground part of the building

- for framed buildings with incomplete framing :

type and dimensions of columns: columns of square section 400 × 400 ;

external walls: made of silicate brick, 0.38m thick.

Technical Requirements for Performance of Works

4.1 Comparison of Options

When comparing the costs of foundations of shallow and pile foundations, it should be noted that when erecting a foundation of shallow foundation on a natural base (no sand cushions, no ramming), such a foundation will be cheaper and more economically profitable than a pile one. Therefore, we accept and draw in the graphic part precisely the foundation of shallow laying.

4.2 Technical Requirements for Performance of Works

All work on the construction of foundations can be divided into such processes as:

- binding of reinforcement frames;

- formwork installation;

- concreting and layer-by-layer compaction of concrete mixture;

- dismantling of formwork;

- waterproofing works;

- backfilling with layer-by-layer compaction of soil.

After the pits and trenches for the foundations are opened, it is possible to geodetic split the foundations, at the entrance of which the axes (intermediate and main) are placed on the pit, and then determine the position of the foundations in the project plan. These foundation locations are indicated in the pit using pegs.

Reinforcement for the framework is knitted directly on the construction site from separate rods using special knitting hooks.

As a formwork, we will accept inventory formwork.

To install and remove the formwork, we will take a caterpillar crane .

Design position of the formwork is checked using geodetic instruments.

Before concreting, it is required to clean the reinforcement from dirt and rust. Concreting of structures is carried out using the Liebherr 50M5 XXT auto-concrete pump, we also use the 58148Y auto-concrete mixer, after supplying the concrete mixture to the place of acceptance eѐ they are laid in a formwork. After the mixture is laid, the concrete mixture should be compacted, the concrete mixture is compacted using the deep vibrator IV112, and the mixture is compacted in layers. When using deep vibrators, it is not allowed to contact during concreting of its tip with reinforcement. The vibration time of the tip in one place is approximately 30 seconds.

After concreting, concrete is maintained, the essence of which is to ensure the most favorable conditions for concrete hardening, since without this concrete may not achieve its design characteristics.

Fracturing can be carried out only after reaching design or fracturing strength, on average after 3-7 days.

After the formwork is removed, waterproofing of the foundations is carried out. After that, the floor slab is installed, which will ensure stability of the foundation during backfilling. After installation of the slab, backfilling of the soil is performed, which is performed as a layer-by-layer, while each layer is compacted with vibration rams or vibration plates.