physics

Persistence (discontinuity)

Persistence (discontinuity) is a physics topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Persistence (discontinuity) rather than just read about it. In short: Persistence determines the possibilities of relative movement along a discontinuity in a soil or rock mass in geotechnical engineering. Discontinuities are usually differentiated in persistent, non-persistent, and abutting discontinuities (figure).

Key takeaways

Persistence (discontinuity) belongs to physics; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Persistence (discontinuity) to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Persistence (discontinuity) from memory before moving on to harder problems.

Reference excerpt

Persistence determines the possibilities of relative movement along a discontinuity in a soil or rock mass in geotechnical engineering. Discontinuities are usually differentiated in persistent, non-persistent, and abutting discontinuities (figure).

Persistent discontinuity A persistent discontinuity is a continuous plane in a soil or rock mass. Shear displacement takes place if the shear stress along the discontinuity plane exceeds the shear strength of the discontinuity plane.

Non-persistent discontinuity A non-persistent discontinuity ends in intact soil or rock. Before movement of the material on both sides of a non-persistent discontinuity is possible, the discontinuity has to extend and break through intact material. As intact material has virtually always far higher shear strength than the discontinuity, a non-persistent discontinuity will have larger shear strength than a persistent discontinuity.

Abutting discontinuity An abutting discontinuity abuts against another discontinuity. Abutting discontinuities might continue at the other side of the intersecting discontinuity, however, with a displacement to give so-called ‘stepped planes’. Shear displacement along the discontinuity can take place if the shear strength along the discontinuity plane is exceeded, and the blocks of material against which the discontinuity abuts can move or break.

Anisotropic persistence A discontinuity might be persistent in dip direction but be not persistent perpendicular to the dip direction or vice versa.

See also Discontinuity (geotechnical engineering) Rock mechanics Shear strength (discontinuity)

References

Illustrations

Worked examples

Example 1 — a first encounter with Persistence (discontinuity)

Start with the simplest possible case. Write down what Persistence (discontinuity) claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In physics, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Persistence (discontinuity) before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Persistence (discontinuity) ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Persistence (discontinuity)

In research: Persistence (discontinuity) appears in physics research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Persistence (discontinuity) in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Persistence (discontinuity) is common in secondary-school and first-year university syllabi. It links to neighbouring topics Rock mass classification, Soil mechanics, so understanding it makes those chapters shorter.
In everyday life: Look for Persistence (discontinuity) outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Persistence (discontinuity) in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Persistence (discontinuity) means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Persistence (discontinuity) out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Persistence (discontinuity) in simple terms?

Why does Persistence (discontinuity) matter?

Because it connects several physics ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Persistence (discontinuity)?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Persistence (discontinuity).