treating subsoil Flashcards
What is the angle of repose for most subsoils during excavation?
Neutral angle of repose
Most subsoils have a neutral angle unless temporary support is provided.
What must be completed when ground is contaminated?
A risk evaluation must be completed
Contaminants may include gases, brownfield sites, and contamination from animals or food.
What are the options for dealing with poor subsoil?
- Not build
- Remove and replace
- Surcharging
- Dynamic compaction
- Vibration
- Jet grouting
These methods help stabilize or improve the subsoil conditions.
What reaction can sulphate cause with concrete oversite?
Weakens its structure
Key components affected include calcium aluminate and calcium hydroxide.
What determines the type of foundation to use?
Existing ground conditions and soil properties
Understanding soil characteristics is essential for foundation design.
What factors must be considered in site remediation?
- Pre remediation
- Time scale
- Cost
- Remedial works planning
- Constraints
- Sustainability
Comprehensive evaluation is crucial for effective site remediation.
What are the three types of treatment for weak soil?
- Not specified in the text
The text does not detail the three types, but other methods are discussed.
What does Insitu contamination treatment involve?
- Enclosing contaminated soil
- Perimeter trench to rock/sound strata
- Filling with impervious agent
- Impermeable horizontal capping
High specification barriers are needed for liquid or gas contaminants.
What are some methods of soil treatment for contamination?
- Soil washing
- Vapor extraction
- Electrolysis
- Biological treatment
- Chemical treatment
Each method targets specific types of contaminants.
What is involved in soil washing?
- Eliminates fuel, metals, and chemicals
- Sifting to remove large objects
- Scrubbing with water and detergents
The scrubbing process is akin to using a concrete mixer.
What does vapor extraction remove?
- Fuels
- Industrial solvents
- Organic deposits
This method uses vacuum piles to draw air through contaminated soil.
What is the process of electrolysis in soil treatment?
Transfer of positive and negative ions between anode and cathode
Metal ions in water accumulate before being pumped to soil for treatment.
What is phytoremediation?
Removal of contaminants by plants
Plants absorb harmful chemicals, which are then harvested and destroyed.
What chemicals are used in soil chemical treatment?
- Liquid hydrogen peroxide
- Potassium permanganate
These chemicals help break down oils, grease, and chemicals in the soil.
What are the two forms of borehole samples?
- Disturbed samples
- Undisturbed samples
Disturbed samples use an auger, while undisturbed samples use a long tube.
What information is included in borehole logs?
- Company name
- Project name
- Date
- Coordinates of the borehole
The log also includes a diagram and depth breakdown of soil contaminants.
What can geotechnical engineers find using borehole logs?
The water table of the ground
This information is crucial for foundation planning and building on site.
