Chapter 3: Ground Improvement Works (1-13) ⑫👷‍♂️ [What is the purpose of ground improvement?]

What is ground improvement?

Ground improvement is a technique that involves applying artificial treatments to weak or unstable ground to enhance its strength and stability.

Buildings, roads, bridges, and river structures are all built on the ground. Therefore, if the ground remains weak, it cannot safely support these structures.

That is why ground improvement is performed to upgrade the ground to a state suitable for the structure.

Why is ground improvement necessary?

If construction is carried out on weak ground,

• building settlement

• structural tilting

• road deformation

• embankment collapse

• liquefaction during earthquakes

and other problems may occur.

Ground improvement is performed to prevent these risks and to create safe, long-lasting structures.

Main purposes of ground improvement

1. Improving bearing capacity

This is one of the most important purposes.

Bearing capacity refers to the ability of the ground to support a structure.

Since weak ground lacks sufficient bearing capacity,

• Buildings

• Bridges

• Retaining walls

• Embankments

cannot be supported.

Ground improvement increases bearing capacity and creates a safe foundation ground.

② Preventing settlement

Consolidation settlement and differential settlement occur in soft ground.

When settlement occurs, it causes:

• building tilting

• road level differences

• structural damage

and other issues.

Ground improvement suppresses settlement and leads to improved structural durability.

③ Improving ground stability

There is a risk of ground sliding or collapsing on slopes and embankments.

Ground improvement increases shear strength, which helps with:

• slope failure prevention

• embankment stabilization

• retaining wall protection

and so on.

④ Preventing liquefaction

In sandy ground with a high groundwater level, liquefaction can occur during an earthquake.

When liquefaction occurs,

• building settlement

• manhole flotation

• ground deformation

and other damage occur.

Ground improvement is also important as a countermeasure against liquefaction.

⑤ Implementing groundwater countermeasures

In places with high groundwater levels,

• spring water

• excavation collapse

• ground softening

occur.

The construction environment is improved using methods such as the well-point method or chemical grouting method.

⑥ Accelerating consolidation

In soft clay ground, consolidation settlement continues for a long period of time.

Therefore,

• paper drain method

• Vertical drain method

• Preloading method

These are used to accelerate consolidation and complete settlement in advance.

Types of ground improvement methods

Surface improvement method

A method for improving shallow soft ground.

Deep mixing method

A method for improving deep soft ground.

Sand compaction pile method

Compacts the ground using sand piles.

Paper drain method

Aims to accelerate consolidation.

Chemical grouting method

Used for ground strengthening and water cutoff measures.

Wellpoint method

Lowers the groundwater level.

What happens if ground improvement is not performed?

If ground improvement is not performed,

• the building may tilt

• the bridge abutment may settle

• Embankment collapse

• Road deformation

• Increased earthquake damage

These can lead to serious problems.

Therefore, ground investigation before construction and the selection of an appropriate ground improvement method are important.

Key points on-site

When selecting a ground improvement method,

• soil type

• groundwater level

• type of structure

• load conditions

• construction period

• cost

and other factors are judged comprehensively.

Selecting a method suitable for site conditions determines construction quality.

Points frequently appearing on exams

In the Second-Class Civil Engineering Construction Management Technician Exam,

• improving bearing capacity

• preventing settlement

• accelerating consolidation

• Liquefaction countermeasures

• Groundwater countermeasures

and other purposes are frequently asked on exams.

In particular,

"improving bearing capacity" and "preventing settlement"

are the most important points.

Tips for memorization

The purpose of ground improvement,

"Support, don't sink, don't collapse, don't lose to water"

is easier to understand if you remember it this way.

• Support → Improving bearing capacity

• Don't sink → Preventing settlement

• Don't collapse → Improving stability

• Don't lose to water → Groundwater countermeasures/Liquefaction countermeasures

If you grasp these four, you can handle the exam.

Summary

The purpose of ground improvement is to improve soft ground to increase bearing capacity, prevent settlement and collapse, and create ground that supports safe structures.

Also, liquefaction countermeasures, groundwater countermeasures, and consolidation promotion are important purposes, and various construction methods are adopted depending on the construction conditions.

In the Grade 2 Civil Engineering Construction Management Engineer exam, not only the characteristics of each construction method but also the purpose of "why ground improvement is performed" is frequently asked, so make sure to understand it thoroughly.

#Grade2CivilEngineeringConstructionManagementEngineer
#CivilEngineeringConstructionManagementEngineer
#CivilEngineering
#ConstructionIndustry
#ConstructionManagement
#GroundImprovement
#SoftGround
#BearingCapacity
#ConsolidationSettlement
#DifferentialSettlement
#LiquefactionCountermeasures
#GroundwaterCountermeasures
#FoundationWork
#EmbankmentWork
#SiteSupervisor
#CivilEngineeringTerms
#QualificationStudy
#NationalQualification
#CivilEngineeringLearning
#TaigaConstructionNotes