What term describes subsurface or physical conditions at a site that differ materially from those indicated in the contract documents?

The term that describes subsurface or physical conditions at a site that differ materially from those indicated in the contract documents is known as "Differing Site Conditions." This concept is vital in construction contracts because it identifies situations where unexpected conditions are encountered that can impact project costs and timelines.

When a contractor discovers that the actual site conditions are significantly different from what was shown or described in the contract documents, this can lead to additional costs, delays, or even require changes in work methods. Recognizing and addressing these differing site conditions allows for fair adjustments to contract terms, protecting both the contractor and the owner from unforeseen problems that could not have been accounted for in the original agreement.

The other terms provided in the options refer to different concepts. Constructive acceleration pertains to situations where a contractor is required to expedite work without a corresponding adjustment in time or compensation. Joint and several liability is a legal term used to describe situations where multiple parties may be held liable for an obligation, creating a shared responsibility among them. A teaming agreement is a contract between two or more parties to collaborate on a project, often used in complex bids or proposals. Therefore, these terms do not pertain to the specific conditions described in the question about subsurface or physical differences at a site.