книги / Interpreting in the Construction Industry Geotechnics and Underground Construction

Soil stabilization methods

Soil stabilization aims at improving soil strength and increasing resistance to softening by water through bonding the soil particles together, water proofing the particles or combination of the two. The simplest stabilization processes are compaction and drainage (if water drains out of wet soil it becomes stronger). The other process is by improving gradation of particle size and further improvement can be achieved by adding binders to the weak soils. Soil stabilization can be accomplished by several methods. All these methods fall into two broad categories, namely:

–mechanical stabilization. Under this category, soil stabilization can be achieved through physical process by altering the physical nature of native soil particles by either induced vibration or compaction or by incorporating other physical properties such as barriers and nailing.

–chemical stabilization. Under this category, soil stabilization depends mainly on chemical reactions between stabilizer (cementitious material) and soil minerals (pozzolanic materials) to achieve the desired effect. Through soil stabilization, unbound materials can be stabilized with cementitious materials (cement, lime, fly ash, bitumen or combination of these). The stabilized soil materials have a higher strength, lower permeability and lower compressibility than the native soil.

The commonly used binders are: cement, lime (quicklime, hydrated lime, and slurry lime), fly ash, and blast furnace slag. Lime stabilizations technology is mostly widely used in geotechnical and environmental applications. Some of applications include encapsulation of contaminants, rendering of backfill (e.g. wet cohesive soil), highway capping, slope stabilization and foundation improvement such as in use of lime pile or lime-stabilized soil columns.

Stabilized soils cannot withstand freeze-thaw cycles. Therefore, in the field, it may be necessary to protect the stabilized soils against frost damage. Shrinkage forces in stabilized soil will depend on the chemical reactions of the binder. Cement stabilized soil are susceptible to frequent dry-wet cycles due to diurnal changes in temperature which may give rise to stresses within a stabilized soil and, therefore, should be protected from such effects.

2) Fill in the blanks with the appropriate words from the text

Soil …………. involves the use of stabilizing agents (binder materials) in

…..soils to improve its geotechnical ……….. such as compressibility, strength, permeability and durability. The components of stabilization ………. include soils and or soil minerals and stabilizing agent or binders (cementitious materials).

KEY: stabilization, weak, properties, technology

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3)Render the essence of the text in Russian using the mind map.

4)The partner simultaneously interprets your talk back into English.

Task 8. Watch the video and put down1) the difference between compaction and consolidation 2) equipment used for compacting different types of soil

https://www.youtube.com/watch?v=qq09VuGYE1E Introduction to Soil Compaction

Mind the words: expulsion =removal; smooth drum roller – гладковальцо-

вый каток, pneumatic roller – пневмокаток, impact roller – ударный каток; dynamic compaction – динамическое уплотнение; vibroflotation technique –

технология виброфлотации.

Task 9. Interpret the text at sight

Vibration of ground surface: This method is used to strengthen the soil by rearranging and compacting coarse granular particles to form stone columns with the ground surface either by using the natural coarse granular soil or by replacement. This is carried out by a large poker vibrator (глубинный виброуплотнитель) which has an effective compacting radius of 1.5m to 2.7m.

This method is used to strengthen the ground to increase the bearing capacity of soil with a range of 200 to 500kN/m2.

Dynamic Compaction of soil: Dynamic Compaction method of improving bearing capacity of soil consists of dropping a heavy weight from a considerable height. This method is particularly effective in granular soils.

Dynamic Compaction of soil

Jet Grouting

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When water is present in the subsoil, it is first drained out before using dynamic compaction method. The pattern, size, weight and height of drop for dynamic compaction are selected to suit each individual site. Generally 3 or 4 drops are made in each position forming a crater up to 2.5 m deep and 5 m in diameter.

Use of dynamic compaction method creates vibrations in the surroundings due to free-fall of heavy weight. This can cause problems in nearby structures and buildings. Therefore, conditions of existing buildings should be considered before using this method for improving bearing capacity of soil.

Jet Grouting (струйная цементация): This method of consolidating ground can be used in all types of subsoil. Jet grouting is done by lowering a monitor probe into a 150mm diameter pre-bored guide hole.

The probe consists of two jets, the upper jet blasts water, concentrated by compressed air to force any loose material up the guide to ground level. The lower jet fills the void with cement slurry which sets into a solid mass.

Task 10. Find the translation of the terms in bold and put down the respective section next to the title.

1. Multi-auger Deep	a) Soil-cement gains strength and reduces compressibility
Soil Mixing (DSM)	faster than conventional soil improvement methods and
	shortens the construction period.
2. Proven Technology	b) The drilling and mixing operation is low noise and low
	vibration, and does not generate dust.
3. Reliable Gain	c) DSM method is an in-situ soil mixing technology that
in Strength	mixes existing soil with cementitious materials using mixing
	shafts consisting of auger cutting heads, discontinuous
	auger flights, and mixing paddles. The mixing equipment
	varies from single to six augers configurations depending on
	the purpose of the deep mixing. The soil-cement produced
	generally has higher strength, less compressibility, and low-
	er permeability than the native soils.
	The cementitious materials are generally delivered in a
	grout or slurry form from ports in the cutting heads located
	in the lower ends of the multiple shafts. The multiple shafts
	consist of mixing paddles or a combination of discontinuous
	auger flights and mixing paddles depending on the soil types
	and the purposes of soil-cement columns.
	DSM is effective for liquefaction mitigationof seismi-
	cally sensitive soil layers, foundation improvement under
	future structures and in-situ stabilization of contaminated
	soils for environmental remediation among other uses.

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4. Environmentally	d) Required strength can be obtained reliably by setting a
Friendly	proper cement dosage according to the conditions of soil to
	be treated.
5. Reduce	e) Since its development in 1975 by the Port and Harbor
Construction	Research Institute of Japanese Ministry of Transportation,
Period	thousands of projects have been completed. It is also proven
	to be effective for liquefaction prevention.
	KEY: 1c; 2e; 3b; 4b; 5a.

Task 10. Draw up a mind map detailing soil improvement techniques based on the material studied.

Task 11

A.Watch the advertizing video Стабилизация грунтов, устройство осно-

ваний at https://www.youtube.com/watch?v=x1WvpVbqnjM

B.Summarize the content in English, stopping the video every minute.

Mind the words:
суглинок – sandy clay, loam	чернозем – humus;
щебень – crushed stone /aggregate;	фреза – milling cutter, cutter, mill

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UNIT 2. TYPES OF FOUNDATIONS

AND METHODS OF CONTROL

Part I

Task 1. Read the text to find answers to the questions:

1.What is the foundation function?

2.How are foundations reinforced?

3.What does the foundation design depend on?

Foundation is the lowest part of the building or the civil structure that is in direct contact with the soil which transfers loads from the structure to the soil safely. Generally, the foundation can be classified into two, namely shallow foundation and deep foundation.

To construct a foundation, trenches are dug deeper into the soil till a hard stratum is reached. To get stronger base foundation concrete is poured into this trench. These trenches are incorporated with reinforcement cage (армокаркас) to increase the strength of the foundation. The projected steel rods (стальная арматура) that are projected outwards act as the bones and must be connected with the substructure above.

The construction of the foundation can be done with concrete, steel, stones, bricks etc. The material and the type of foundation selected for the desired structure depends on the design loads and the type of underlying soil.

The design of the foundation must incorporate different effects of construction on the environment. For example, the digging and piling (забивка свай) works done for deep foundation may result in adverse disturbance to the nearby soil and structural foundation. These can sometimes cause the settlement (осадка) issues of the nearby structure.

Task 2. Summarize the role of foundations in 1 sentence. Role of Foundations

1.Transfer the building load to the ground.

2.Anchor (крепить) the building against wind and seismic load.

3.Isolate the building from frost heaving (морозное вспучивание).

4.Isolate the building from expansive soils (расширяющиеся грунты).

5.Holds building up from moisture.

6.Provide living spaces (basement, storage).

7.Houses mechanical systems.

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Task 3. Find the translation of the terms on the drawing

Memorize the following:

Types of Foundation and their Uses

1.Shallow foundation – фундамент мелкого заложения

2.Individual /isolated footing – отдельный / столбчатый фундамент

3.Combined footing – комбинированный (монолитный) фундамент

4.Strip foundation – ленточный фундамент

5.Raft or mat foundation – сплошной фундамент, опорная плита, основание (фундамента); свайный ростверк

II. DeepFoundation – фундамент глубокого заложения

1.Pile foundation – свайное основание /фундамент

2.Drilled Shafts or caissons (буровые сваи или свайные колонны / кессонные сваи)

Task 4. Look up other combinations with the words foundation and footing in the dictionary entries

Task 5. Translate the text at sight

Pile Foundations

Pile foundation is a type of deep foundation which is used to transfer heavy loads from the structure to a hard rock strata much deep below the ground level.

Pile foundations are used to transfer heavy loads of structures through columns to hard soil strata which are much below ground level where shallow foundations such as spread footings and mat footings cannot be used. This is also used to prevent uplift of structure due to lateral loads such as earthquake and wind forces.

Pile foundations are generally used for soils where soil conditions near the ground surface is not suitable for heavy loads. The depth of hard rock strata may be 5m to 50m (15 feet to 150 feet) deep from the ground surface.

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Fig. Pile Foundation

Pile foundation resists the loads from structure by skin friction (поверхност-

ное трение) and by end bearing (концевая опора). Use of pile foundations also prevents differential settlement of foundations.

Task 6. Look up the types of piles in the dictionary entry and memorize them

Task 7. Take turns to read and translate the texts

	Memorize the following:
Shaft – зд. колонна		Fieldstone – валун, булыжник
Toe – пята		Reinforced concrete – железобетон
Auger (['ɔːgə] – бур		Gabion ['geɪbɪən] – габион
Retaining wall – подпорная стенка		Reinforced earth – армированный грунт
Backfill – засыпка		Timber – крепежный лесоматериал

A. Drilled Shafts or Caisson Foundation. Drilled shafts, also called caissons, are a type of deep foundation and have action similar to pile foundations discussed above, but are high capacity cast-in-situ foundations. They resist loads from

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structure through shaft resistance, toe resistance and / or combination of both of these. The construction of drilled shafts or caissons is done using an auger.

B. Retaining walls are structures that support backfill and allow for a change of grade. For instance, a retaining wall can be used to retain fill along a slope or it can be used to support a cut into a slope.

Walls might be constructed from materials such as fieldstone, reinforced concrete, gabions, reinforced earth, steel and timber. Each of these walls must be designed to resist the external forces applied to the wall from earth pressure, surcharge load, water, earthquake, etc.

Task 8. Draw a mind map detailing the information about foundations, their types and functions

Part II

Non-destructive testing (NDT) of existing structures is an important tool in ensuring their safety. It involves the use of methods such as wave propagation, electromagnetism, electrical conductivity, and thermal conductivity to test structural integrity and thereby allow nondestructive assessment of structures and the possibility of structural failures before they occur.

Task 9. Read the texts and make a list of NDT methods and properties of concrete they measure

Memorize the following:

Specimens cast – литые образцы	Penetration test – испытание на пенет-
	рацию / зондирование
Strength – прочность:	Rebound test – тест на отскок
compressive – на сжатие,
flexural – на изгиб
tensile – на растяжение /разрыв
Projectile [prə'ʤektaɪl]- забиваемый	Pull-out techniques – зд. испытания
предмет	на выдергивание
Rebound capacity – упругость, спо-	Maturity concept – понятие зрелости
собность восстановления после де-	(степени отвердения бетона)
формации

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Non-destructive testing of concrete

The standard method of evaluating the quality of concrete in buildings or structures is to test specimens cast simultaneously for compressive, flexural and tensile strengths.

Certain physical properties of concrete can be related to strength and can be measured by non-destructive methods. Such properties include hardness, resistance to penetration by projectiles, rebound capacity and ability to transmit ultrasonic pulses and X- and Y-rays.

These non-destructive methods may be categorized as penetration tests, rebound tests, pull-out techniques, dynamic tests, radioactive tests, maturity concept. It is the purpose of this Digest to describe these methods briefly, outlining their advantages and disadvantages.

Methods of Non-Destructive Testing of Concrete

1.Penetration method – зондирование

2.Rebound hammer method – метод отскока молотка

3.Pull out test method – испытание на растяжение

4.Ultrasonic pulse velocity method – ультразвуковой импульсный метод

5.Radioactive methods – радиометрические методы

Task 10

A.Read the text and summarize its content in Russian.

B.The partner should simultaneously interpret the summary back into English in whisper.

Penetration Tests on Concrete

The Windsor probe is generally considered to be the best means of testing penetration. Equipment consists of a powder-actuated gun (пороховой пистолет) or driver, hardened alloy probes, loaded cartridges, a depth gauge for measuring penetration of probes and other related equipment.

Calculations performed to estimate settlement in coarse-grained material are usually undertaken using empirical methods based on data obtained during the exploration program. Since it is expensive and impractical to obtain “undisturbed” samples of coarse-grained material for laboratory testing, predictions are based on field-testing methods such as the standard penetration test (SPT), cone penetration test (CPT – зондирование конусным наконечником), dilatometer test (DMT – испытание дилатометром) and the pressuremeter test (PMT – прес-

сиометрическое испытание). Researchers have synthesized information collected from testing programs and studies and have developed a number of empirical relationships to estimate the settlement of footings underlain by granular soil.

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Task 11. Dynamic Non Destructive Tests on Concrete

A. Arrange the text paragraphs in the logical order.

The Ultrasonic Pulse Velocity Method

a)Pulse velocity tests can be carried out on both laboratory-sized specimens and completed concrete structures, but some factors affect measurement.

b)The fundamental design features of all commercially available units are very similar, consisting of a pulse generator and a pulse receiver.

c)In summary, ultrasonic pulse velocity tests have a great potential for concrete control, particularly for establishing uniformity and detecting cracks or defects. Its use for predicting strength is much more limited, owing to the large number of variables affecting the relation between strength and pulse velocity.

d)Pulses are generated by shock-exciting piezo-electric crystals, with similar crystals used in the receiver. The time taken for the pulse to pass through the concrete is measured by electronic measuring circuits.

e)At present the ultrasonic pulse velocity method is the only one of this type that shows potential for testing concrete strength in situ. It measures the time of travel of an ultrasonic pulse passing through the concrete.

f)The pulse velocity method has been used to study the effects on concrete of freeze-thaw action, sulphate attack, and acidic waters. Generally, the degree of damage is related to a reduction in pulse velocity. Cracks can also be detected.

KEY: e), b), d), a), f), c)

B. Read the text and answer the questions:

1.What does the method measure?

2.Where is it used?

3.What does it detect?

Task 12. Read and translate the text at sight

Memorize the following:

Honeycombing – щербатость, пористая	Delaminated – отслоившийся
поверхность;
Honeycombing concrete – раковистый бетон
Sounding – зондирование	Voids – пустоты, поры
Spalled – сколотый

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