Foundation cylinders and caissons

44 Pages·02.929 MB·Russian

by  Коллектив авторов

Министерство образования и науки Российской Федерации
Сибирский федеральный университет

Foundation cylinders and caissons

Учебно-методическое пособие

Электронное издание

Красноярск
СФУ
2017
УДК 624.157.2/.3(07)
ББК 38.582.4я73
F81

Составитель: Преснов Олег Михайлович

F81 Foundation cylinders and caissons : учебно-методическое
пособие [Электронный ресурс] / сост. О.М. Преснов. – Электрон.
дан. – Красноярск : Сиб. федер. ун-т, 2017. – 44 с. – Систем.
требования: PC не ниже класса Pentium I; 128 Mb RAM; Windows
98/XP/7/8/10; Adobe Reader V8.0 и выше. – Загл. с экрана.

Содержит краткий теоретический материал по опускным колодцам и
кессонам.
Предназначено для студентов направления 08.03.01 «Строительство».

УДК 624.157.2/.3(07)
ББК 38.582.4я73

© Сибирский федеральный
университет, 2017

Электронное учебное издание

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E-mail: [email protected]
CONTENTS
INTRODUCTION……………………………………………………………….4
1. FOUNDATION CYLINDERS…………………………………………….5
1.1. Foundation cylinders’ classification………………………………...5
1.2. Foundation cylinders’ design technology…………………………...8
2. THE CAISSONS’ FOUNDATION………………………………………11
2.1. Classification of caissons…………………………………………..12
2.2. Caissons’ construction and settling equipment………………….....13
2.3. Caisson work technology…………………………………………..16
3. DIMENSIONING OF FOUNDATION CYLINDERS AND
CAISSONS……………………………………………………………….18
3.1. Calculation for penetration………………………………………...19
3.2. Cylinder calculation for floating up………………………………..20
3.3. Problem-solving examples…………………………………………20
APPENDIX 1. TEST VARIANTS……………………………………………...31
APPENDIX 2. CLASSIFICATORY VALUES OF SANDY AND CLAY
SOIL……………………………………………………………………………..40
BIBLIOGRAPHIC LIST………………………………………………………..44

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INTRODUCTION

The purpose of the study-guide is to give students an opportunity to deepen
knowledge and reinforce a skill in foundation cylinders and caissons. During the
theoretical part of the course, students have to complete the test, using examples
and recommendations, and literature reference material from the appendix.
The test includes five problems and one written task. The first problem is to
design characteristics of foundation soil. The second is to design the diameter of
the foundation cylinder. Third and fourth are to calculate the cylinder for floating
up and penetration. The fifth is to design caissons settlement. The sixth is to
answer on three questions in written form. There are 32 variants for problems (1-
32). The 32nd variant is an example. Student chooses the variant according to his
number in rolls. This work has to be arranged on A4 format lists. Calculations have
to be followed by graphs and schemes.

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1. FOUNDATION CYLINDERS.
Foundation cylinder – hollow-core construction, opened form the top and from
the bottom, down-dropped under the load influence or gravity.
Benefits of foundation cylinders:
 Great horizontal and vertical load transmission on the soil against the
backdrop of big sections
 Deep penetration (lower than the water level = 40 m)
 There is no need in special equipment
 Lack of vibration allows you to locate ones in constrained conditions
 Intrusive geodesy and technical monitoring during the downwarping of the
foundation cylinder

1.1. Foundation cylinders’ classification
Foundation cylinders classified by following characteristics:
 Form of vertical sections: cylindrical, cone and cone-stepped (table 1.1);
 Form of the cylinder in plain view: circular, rectangular, square, with round
side walls (table 1.2);
 Material: reinforced concrete, concrete, metal, wooden, flinty, masonry;
Clear width of circular ccylinders and dimensions of rectangular cylinders should
be taken from 6 to 24 m – divisible by 3, but from 24 to 60 – divisible by 6. Depth
should be divisible by 1m, height of knife console – by 0,2 m.
The shoe of the cylinder is better to be made of reinforced concrete.
The shoe of the cylinder must overlap the edge of the wall 100-150 mm to
indicate the split to reduce the friction while downwarping.
There are 6 main different types of shoes according to foundations. Type of
the shoe elevations depends on following characteristics:
 Soil type
 Cylinder construction

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Table 1.1
Vertical section forms of foundation cylinders
№ Scheme of the section Name of the section
1 Cylindric

2 Cone

3 Cone-stepped

Table 1.2
Form of foundation cylinders in plain
№ Scheme of the foundation cylinder Form of the foundation cylinder
1 Circular

2 Rectangular

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End of table 1.2
3 Square

4 With round side walls

*N.b. 1 – the wall, 2 – bottom of the cylinder, 3 – cross-wall

Table 1.3
Shoe elevations types of foundation cylinders
№ Scheme Name
1 On the embedded sand cushion and wooden gobb

2 On the sand cushion in bulk and wooden gobbs

3 On the wooden prism in bulk

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End of table 1.3
4 In the special prepared cut (working trench)

*N.b. 1 – cylinder shoe; 2 – wooden gobb; 3 – sand cushion; 4 – wooden timbering or
reinforced-concrete shell-slab

It is clear from the Table 1.4 that methods of locating a shoe on the foundation
such as sand cushions and wooden gobbs are the most widespread.

1.2. Foundation cylinders design technology
Foundation cylinders installation is accomplished in the following sequence:
1) Cylinder design
2) Cylinder downwarping
3) Building-up walls due to downwarping (if needed)
Design starts with construction of temporary support for the shoe. Wooden
gobbs could be taken as a temporary supports, shared across the perimeter. First
step of the design is carried out by downwarping the first layer with shoe not less
than 5 m. Then, levels are build up steadily to the overall height of 4-6 m.
Silent pile drivers are used to embedment thin-walled foundation cylinders.
This method is used to downwarp foundation cylinders into wet sandy, sandy loam
and clay loam.
Rigging up of cylinders from vertical prefabricated panels reduce the length of
construction and labour intensity. The drawback of the prefabricated foundation
cylinder is its small weight, which cannot allow to stabilize the cylinder, locating
under the ground water level, what requires extra equipment to prevent it from
uplift.
In the past few years, hollow archy blocks are applied, constructed with binding
of stones, uniting by looping joint. Unit-construction solid-cast variant of
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foundation cylinder is widely used. Cutting unit is made of insitu reinforced
concrete, and two-core concrete block are built up on the edge of the cylinder,
made on the flat of a matrix (figure 1.1. b). Blocks are stick together with vertical
units, hearted in concrete. This construction is widely used in big foundation
cylinders with diameter larger than 20 m and penetration 30-40 m. The main
drawback is overuse of materials in units and construction of matrix.
To overcome the force due to friction tickstrope cover is used. This is made to
prevent the cylinder from downwaroing and anticipated arching.
Tickstrope cover is a special loam solution layer filled up between vertical
ground shaft wall (working trench) and the top exterior face of the cylinder.
Function of the cover is to reduce the friction force; prevention of destruction and
slipping of vertical ground walls because of forces created by matrix.
a a) Made of vertical panels

b b) Made of blocks

Figure 1.1. Unit-construction foundation cylinder
1 – panel; 2 – foreshaft; 3 – tickstitrope cover; 4 – blocks; 5 – shoe; 6 – insitu
reinforced concrete band

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Unification of space planning and constructive decisions of foundation
cylinders is one of the main ways lead to industrial planning. Such decisions allow
once to use projects of foundation cylinders more than once. In designing industry
cylinders are constrained by specifications.
Consistent reinforced concrete foundation cylinders are widely used with
diameter from 8 to 24 m. Concrete panels foundation cylinders are used with the
lengths of panels 11,5 m, width to 1400 mm and thickness 450 mm. (Table 1.5)
From the external side of the cylinder walls are stick together with metal
slab with overall width 50 mm, thickness 12 mm, pitch 200 mm. From the internal
side solid-core metallic slab is welded on.
Table 1.5
Consistent characteristics
Cylinder Number of Geometrical dimensions, mm
diameter panels a a b b
1 1
8 17 104 248 220 450
10 21 115 231 240 430
12 25 122 220 240 420
14 30 77 159 200 360
16 34 88 160 210 360
18 38 95 159 220 360
20 42 102 160 220 360
22 46 109 162 230 360
22 47 76 128 200 360
24 50 113 162 230 360
24 51 84 132 200 330

Depending on the function, dimensions in plain, hydrogeological conditions
and cost-effectiveness following downwarping methods are used: earthworks
absent with ground water and earthworks on the water-cut territory.
Absent with ground water or in water depression conditions push-type scrapers and
backdiggers are used for earthworks in a working trench (figure 1.2.) Upcast is
lifting to the surface with bailer. This method is acceptable in free-open-texture
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