JNTU B.Tech III ROCK MECHANICS ENGINEERING Previous Question Paper (February - 2023 - R18)

Find out Particle or grain density of a soil sample that has a bulk density of 1.55 g/cm3 and a porosity of 40%.

Differentiate between stress and strength.

Differentiate between Active and Passive support.

Classify the artificial support for ground control.

List the purpose of Convergence indicators.

List the different types of slope failures that may take place in opencast mines.

What is a wedge failure?

State the purpose of anchorage testing equipment.

What is Mohr’s theory of failure?

Define the term Gas outbursts.

Distinguish between an elastic and plastic rheological models.

Distinguish between Protodyaknov index and Impact Strength index from strength determination point of view.

In a field density test of an overburden, the following results are obtained; Soil density ρ = 1.95 Mg/m3, Moisture content w =16%, Specific gravity of solids is 2.7. Find dry density, void ratio, air content, degree of saturation.

Explain the method determining slake durability index of rocks.

Discuss the distribution of induced stress on a square pillar by neat sketches.

Explain supports at the junctions.

Describe the design of systematic support rules for B&P and Long wall (Face and Roadways)

Different variations of Chock support and their stress vs. strain characteristics.

Compare the working principle of flat jack. Over coring and hydro-fracturing techniques for in-situ stress measurement.

A surface mine is operated with two overburden benches as shown in figure. Upper bench face FD is moving 10 m ahead of the lower bench face AB. The Cohesion and angle of internal friction of the failure plane (AA′) are 10 k Pa and 30 deg., respectively. The rock mass unit weight is 22 k N/m3. Find the slope factor safety.

For in-situ strength measurement, all the tests are carried out with different loading conditions as mentioned below. Why? i) Cyclic Loading ii) Incremental Loading iii) Creep loading

By schematic diagram, discuss the modes of slope failure.

With neat sketches, draw and briefly explain the curves: i) Vertical subsidence ii) Horizontal strain

Describe the surface, underground, and face arrangements for stowing practice.

Explain the subsidence prediction techniques.

What is hydraulic profile with reference to hydraulic stowing arrangement in an underground mine?

Describe the Grififith theory failure and their field of application.

Explain the rock burst phenomena, causes, prediction.

A bord and pillar operation is planned at a depth of 300 m in a strata of average unit weight 24.5 kN/m3 and compressive strength 15.50 MPa. If the width of the opening is 6m considering a factor of safety of 1, calculate the maximum possible extraction ratio in percentage?

Describe the stress distribution in underground workings in Bord and Pillar.