JNTU
JNTU B.Tech III ROCK MECHANICS Previous Question Paper (January/February - 2023 - R18)
Note: i) Question paper consists of Part A, Part B. ii) Part A is compulsory, which carries 25 marks. In Part A, Answer all questions. iii) In Part B, Answer any one question from each unit. Each question carries 10 marks and may have a, b as sub questions.
Part A
Write about formation of sedimentary rocks.
Answer
Sedimentary rocks are formed through the weathering, erosion, transportation, and deposition of pre-existing rock fragments or organic material. These sediments accumulate in layers, undergo compaction (overburden pressure), and cementation (precipitation of minerals like silica or calcite), a process collectively known as lithification.
Define specific gravity of rocks and write its typical range for rocks.
Answer
Specific gravity of rock is the ratio of the unit weight of the rock material to the unit weight of water at a standard temperature. For most common rocks, the typical range is between 2.0 and 3.0.
Write the importance of Q index formula.
Answer
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Write the importance of slake durability index in rock engineering.
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Write the correction to be applied for point load index.
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How do you know a given rock is fractured rock?
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How do you control rock fall?
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Write about planar failure of rocks.
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Which explosive is used commonly in blasting? Write its chemical composition.
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What are the blasting parameters?
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Part B
What are various physico - mechanical properties of rocks? Explain what is porosity and write the visual representation of porous rock.
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What is Rock Quality Designation? Discuss how do you measure it and also write its practical use.
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Discuss in detail the various parameters used in RMR and RSR classification systems and write relative merits of RMR and RSR systems.
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Explain with neat sketches, how do you conduct plate bearing test in an underground? Also discuss the interpretation of test results.
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Explain with neat sketches how do you conduct in-situ tests such as seismic cross hole test and borehole shear test? Discuss the interpretation of their results.
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What is the difference between intact rock and rock mass? How do you estimate intact rock strength? Explain.
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Discuss with clear illustrations a unified strain – hardening and strain-softening elastoplastic constitutive model for intact rocks.
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Discuss various factors that result in rock slope failure. Explain kinematic analysis of wedge failure.
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What are the reasons for toppling failure of rock? Discuss with clear illustrations, the stability equations for toppling failure.
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What is the purpose of blasting in underground mines? Discuss the principle of blasting.
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How many types of blasting are there in underground mines? Explain.
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Describe with clear illustrations pre-split blasting design method and explain the advantages of this method in underground mining.
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