Soil mechanics, foundations and foundations

Contents

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 = 1450 kN, Mon = 146 kNm).

In the course design, the values ​ ​ of design loads on the foundations NoI, NoII, MoI, MoII can be accepted :

- 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 three-span industrial building:

• type and dimensions of columns: columns of rectangular continuous section K126, with a section of 500 × 600.

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

Foundation arrangement includes the following technological processes:

- 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.

Geodetic breakdown of foundations is performed after passage to pits for foundations. The breakdown consists of moving the main and intermediate axes of the buildings to the pit first, and then determining the position of each foundation according to the project. The location of the foundations on the ground is fixed with wooden necks .

Reinforcement frames are tied by hand with wire from separate rods directly on the construction site before installation of the formwork.

The use of industrial construction methods leads to the use of inventory formwork. As a formwork, we will use inventory block forms.

Installation and removal of the formwork is carried out using a caterpillar crane (MKG25BR ).

Geodetic instruments are used to adjust position of each block-form to design position.

Before concreting it is necessary to check the quality of rust cleaning of reinforcement. When laying concrete mixture in reinforced structures, the free drop height (up to 3 m) must be observed.

The concrete mixture will be supplied to the construction site by a concrete mixer. The concrete mixture is unloaded into rotary trays, from which later, using a caterpillar crane (MKG25BR), the concrete mixture enters the formwork .

Consolidation of concrete mix is carried out layer-by-layer, by means of the deep IV117A vibrator. No contact between the vibrator and the fittings is allowed during vibration. Vibration time is determined experimentally (optimal duration of vibration of the mixture in one place from 20 to 30 s), as a result of visual inspection

After laying and compacting the concrete mixture, it is necessary to create favorable conditions for its hardening in order to achieve the required physical and mechanical properties. To this end, we care for concrete until it reaches its design strength. Decay is carried out after 4 days.

After disassembly of the formwork, it is necessary to perform waterproofing of the foundation surface, at the end of which backfill with layer-by-layer compaction of the soil with pneumatic rams.