Can deep excavations near you affect your property?

September, 30 2020

Construction projects in congested environments, such as cities, often require heavy vibrating equipment and deep excavations close to nearby structures. These hazardous activities require careful engineering and planning to prevent nearby structures and buildings from sustaining joint damage.

How can deep excavations lead to damage?

Buildings built onto compressible and loose soil can benefit from the support of sheet piles, which are usually installed by impact driving. However, to extract and drive these sheet piles, construction workers often use vibrating equipment. During the impact driving process, the sheet pile is put under short stress waves, causing vibrations that diffuse from the shaft of the pile directly into the soil.

The more intense the stress wave is, the lower the ground vibrations will be, and the larger the force required. In addition to the intensity of these vibrations, the frequency also affects the surrounding structures. When the resonance frequency of the surrounding building elements coincides with the vibrations’ dominant frequencies, this can increase the risk of building damage.

What kind of building damage can occur?

When you’re assessing your construction project’s risk, it’s important to figure out what kind of damage could occur to the buildings that surround your project. It’s also important to be aware that damage can occur to buildings as a result of the secondary effects of vibration via the soil’s settlement.

Damage to foundations and buildings can be classified into four categories:

Damage category I

This damage category is caused by static ground movements, which occur in the area where the deep excavation is taking place. After installing displacement piles, this can lead to lateral and heave displacements, causing damage to buildings. The movement of static soil can also be caused by the movement of adjoining slopes triggered by vibrations.

Damage category II

The distortion of the ground causes this damage category. When the vibration waves move along the soil’s surface, the foundations of nearby buildings can be subjected to several downward and upward movement. The risk of nearby buildings being damaged is largest when the building is as long as around half of the vibration wavelength.

Damage category III

This damage category is caused by settlement as a result of ground vibrations. This settlement is most significant in granular, loose soils such as silt and sand.

Damage category IV

Dynamic effects within the building itself cause this damage category.

Are you looking for vibration monitoring services to assess the potential damage caused by your construction project? Contact us and maximize your project’s productivity and profitability in Southern California by supporting it with our geotechnical and geological experience.


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