Your Answer : (Not Answered)

Correct Answer : A

Correct answer: 36.7 per cent

The rock quality designation counts only sound pieces 100 mm or longer, so the 90 mm piece is excluded: \[ \frac{400 + 300 + 250 + 150}{3000} = \frac{1100}{3000} = 36.7\ \mathrm{per\ cent}. \] Against a recovery of 80 per cent this is a poor rock mass - the difference between the two figures is a measure of how broken the core is.

Your Answer : (Not Answered)

Correct Answer : C

Correct answer: the assertion is false although the reason offered is a true statement in itself

The reason is a true general statement, but it does not support the assertion, which is the reverse of the truth. Bursts require rock strong and brittle enough to store elastic strain energy and release it suddenly, under a stress close to its strength - which means hard rock at depth. Weak clayey ground yields gradually and squeezes instead.

Your Answer : (Not Answered)

Correct Answer : C

Correct answer: a steady advance rate in uniform sound rock

A steady advance in sound rock is the absence of a warning, not a warning. The other three all indicate deterioration ahead or around: convergence increasing behind the face means the ground is still moving, a fall in RQD from probe cores means the rock ahead is broken, and a sudden increase in inflow means a water-bearing zone is being approached.

Your Answer : (Not Answered)

Correct Answer : B

Correct answer: the degree of jointing of the rock mass

Rock quality designation is computed from a core run as the percentage made up of intact pieces longer than 100 mm, so it measures how closely the mass is broken by discontinuities rather than how strong the rock itself is. That is why it appears in classification systems alongside a separate term for intact strength.

Your Answer : (Not Answered)

Correct Answer : A

Correct answer: the presence of an overlying bed of much lower permeability

Confinement is defined by what lies above the aquifer, not by the aquifer itself. The same sand may be unconfined where it outcrops and confined where a clay covers it downdip. Porosity, grain size and the depth of the wells drilled into it are all properties of the aquifer or of how it is exploited, and none of them determines whether it is confined.

Your Answer : (Not Answered)

Correct Answer : B

Three quite different geological settings produce large earthquakes in India, and the structures involved differ in each. Knowing which applies tells the engineer what kind of rupture and what kind of ground motion to expect.

Your Answer : (Not Answered)

Correct Answer : B

Water pressure penetrating a fault lowers the effective normal stress and so the frictional resistance, allowing accumulated strain to release. Koyna remains the most studied Indian case, and the loading rate matters as much as the depth.

Your Answer : (Not Answered)

Correct Answer : C

Shaking adds a horizontal force to a slope whose factor of safety is already near unity, which is enough to start movement. Mapping marginally stable slopes is therefore part of any seismic hazard assessment in hill country.

Your Answer : (Not Answered)

Correct Answer : C

Correct answer: 1-Q, 2-P, 3-R

The three features record three quite different processes. Slickensides are polished striations produced by blocks grinding past each other, so they mean fault movement. Columnar jointing is a primary igneous feature produced by contraction as a lava or sill cools. Sheet jointing forms as erosion removes the overburden and the rock expands upward, so it records unloading rather than any tectonic event.

Your Answer : (Not Answered)

Correct Answer : B

Correct answer: 25 degrees

Hade is measured from the vertical and dip from the horizontal, so the two are complementary:

The steep fault has a small hade. Answering 65 degrees confuses the two conventions, which is exactly what the question tests.

Your Answer : (Not Answered)

Correct Answer : D

Correct answer: a normal fault

A normal fault drops the hanging wall, so beds slide past one another and part of the sequence is cut out where the hole crosses the plane. The amount missing gives a minimum estimate of the throw. The converse test applies to reverse and thrust faults, which repeat beds rather than omitting them.

Your Answer : (Not Answered)

Correct Answer : D

Correct answer: its strike together with its dip

A plane in space needs two quantities to fix its orientation, and strike and dip are the pair conventionally used. Either alone leaves a whole family of possible attitudes, and outcrop width fixes neither, depending as it does on the thickness and the dip together.

Your Answer : (Not Answered)

Correct Answer : B

Correct answer: younger rock entirely surrounded by older rock

An outlier is a remnant of a formation left standing after erosion has removed the rest, so the younger rock survives as an island in the middle of older ground - typically capping a hill. Its opposite is an inlier, where erosion has cut through younger cover to expose older rock beneath.

Your Answer : (Not Answered)

Correct Answer : D

Correct answer: hard, tough and chemically inert

Quartzite is almost pure quartz recrystallised into an interlocking mosaic, so it is very hard, tough and chemically unreactive - excellent aggregate that resists abrasion and does not react with cement. Those same properties make it expensive to drill, blast and crush, so it is difficult to excavate for the same reason it is valuable once excavated.

Your Answer : (Not Answered)

Correct Answer : C

Correct answer: orthoclase feldspar

Ferromagnesian means containing iron and magnesium, and augite, hornblende and olivine all do, which is why all three are dark and all three weather relatively readily. Orthoclase is the potassium feldspar and contains neither, which is why it is pale and why granite looks as it does.

Your Answer : (Not Answered)

Correct Answer : B

Correct answer: silicon-oxygen tetrahedron

Every silicate is built from a silicon atom surrounded by four oxygens at the corners of a tetrahedron. The whole classification of the silicates follows from how those tetrahedra are joined - isolated, in chains, in double chains, in sheets or in a framework - and so, in turn, do their cleavage and their hardness.

Your Answer : (Not Answered)

Correct Answer : B

Each branch asks a different question of the same rocks, and an engineering problem usually needs several of them at once. A tunnel needs the petrology for the material, the stratigraphy for what lies ahead and the hydrogeology for the water.

Your Answer : (Not Answered)

Correct Answer : B

Correct answer: 25 to 30 degrees Celsius per kilometre

This average is the figure to work from in the absence of local measurement, and it governs the temperature to be expected in a deep tunnel or mine. It cannot be extrapolated far - maintained to 100 km it would give impossible temperatures, and in fact the gradient falls off sharply below the crust.

Your Answer : (Not Answered)

Correct Answer : B

Correct answer: shear waves do not pass through it

A shear wave requires the medium to resist a change of shape, and a liquid does not, so S waves cannot propagate through the outer core. The resulting shadow zone over more than half the globe is the direct evidence, and it is one of the clearest inferences in the whole of geophysics.

Your Answer : (Not Answered)

Correct Answer : C

Correct answer: core

The primary division is compositional: a thin crust of light silicates, a thick mantle of denser silicates, and a metallic core of iron and nickel. The lithosphere and asthenosphere are a different division of the same material, made on mechanical rather than compositional grounds, and the Moho is a boundary rather than a layer.