CPCS Ground Conditions & Stability

Question 1

Why are ground conditions critical to construction plant stability?

Accepted Answer

Soft or unstable ground can cause plant to sink, tilt, or overturn, especially during lifting operations

Answer

Ground conditions only affect tracked plant, not wheeled machines

Answer

Ground conditions are only relevant when it is raining

Answer

Stability only matters when the plant is moving

Question 2

What is 'bearing capacity' of the ground and why does it matter for plant operations?

Accepted Answer

The maximum load per unit area the ground can support without failing — plant must not exceed this

Answer

The depth to which plant tracks must be embedded

Answer

The speed at which plant can travel over soft ground

Answer

The number of plant items that can work in the same area

Question 3

How can outrigger pads help with ground stability during crane operations?

Accepted Answer

They spread the outrigger load over a larger area, reducing ground pressure to within the ground's bearing capacity

Answer

They increase the crane's lifting capacity

Answer

They are only used on soft sand and have no effect on normal ground

Answer

They are decorative and have no structural function

Question 4

What should be checked regarding underground voids before operating heavy plant?

Accepted Answer

The location of any cellars, culverts, tunnels, or buried services that could collapse under plant weight

Answer

Only surface drainage channels

Answer

Voids are not relevant if the ground looks firm at the surface

Answer

Only voids deeper than 3 metres are a concern

Question 5

What is the risk of operating plant on a slope steeper than the manufacturer's specified gradient?

Accepted Answer

The plant may overturn laterally or tip forward, causing serious injury or death

Answer

Operating on slopes only affects fuel efficiency

Answer

Slopes only affect visibility, not stability

Answer

Gradients are only relevant for loaded vehicles

Question 6

Before placing a crane on outriggers, what ground investigation should be carried out?

Accepted Answer

Check for underground services, voids, and confirm ground bearing capacity is sufficient for the outrigger loads

Answer

Only a visual surface inspection

Answer

Outrigger placement is the crane operator's decision alone

Answer

A ground investigation is only needed if the crane weighs over 50 tonnes