Untitled Quiz

<p>During feasibility and preliminary design stages (B)</p> Signup and view all the answers

<p>Joint Spacing (C)</p> Signup and view all the answers

<p>The continuity of joints in rock (D)</p> Signup and view all the answers

<p>The number of joints per unit volume of rock (A)</p> Signup and view all the answers

<p>It assesses the in-situ stresses affecting the tunnel. (B)</p> Signup and view all the answers

<p>0.57 (C)</p> Signup and view all the answers

<p>Ja (D)</p> Signup and view all the answers

<p>It relates to the intended use and degree of security of the excavation support system. (D)</p> Signup and view all the answers

<p>The equivalent dimension of the excavation (C)</p> Signup and view all the answers

<p>High stability after 1 hour in massive rock (C)</p> Signup and view all the answers

<p>The roughness of the most unfavorable joint (A)</p> Signup and view all the answers

<p>The amount of rock core recovered in drill samples (C)</p> Signup and view all the answers

<p>The loosening load in the case of excavation (B)</p> Signup and view all the answers

<p>It can cause softening and possible out-wash in clay-filled joints (A)</p> Signup and view all the answers

<p>JA (C)</p> Signup and view all the answers

<p>They are smooth and wavy (D)</p> Signup and view all the answers

<p>The amount of water pressure on joints (D)</p> Signup and view all the answers

<p>Loads experienced by plastic incompetent rocks (C)</p> Signup and view all the answers

<p>Less than 3 meters (C)</p> Signup and view all the answers

<p>Cable Bolts (C)</p> Signup and view all the answers

<p>$L = rac{Span}{2} + 0.15 imes ESR$ (D)</p> Signup and view all the answers

<p>Punching (A)</p> Signup and view all the answers

<p>Rapid early strength development (D)</p> Signup and view all the answers

<p>Shear strength maintenance (D)</p> Signup and view all the answers

<p>Fibers (B)</p> Signup and view all the answers

<p>Compression / Tension (B)</p> Signup and view all the answers

A laboratory-measured property describing the strength of the rock material itself, without considering the effects of fractures or joints.

The stresses acting on rock in its natural, in-situ environment.

Water present within the rock mass, potentially affecting its stability and strength.

Assessment of the quality of rock cores collected from drilling, including their fracture density.

The distance between fractures or joints within the rock mass.

The length of a fracture or joint within the rock mass.

Schemes used to describe a rock mass based on its composition and characteristics to predict support requirements and strength/deformation behaviour, typically used during feasibility/design.

The direction and angle of joints or fractures in the rock mass.

Rock Quality Designation, a measure of the quality of rock core obtained from drilling, indicating the degree of fracturing and jointing.

A ratio used to estimate the required length of rock bolts based on the span of the excavation and the rock mass's strength.

The length of a rock bolt installed in the rock mass to provide support, estimated based on the excavation span and ESR.

Short rock bolts (typically less than 3 meters long) used for reinforcement in underground excavations.

Long rock bolts (typically greater than 5 meters long) used for reinforcement in underground excavations.

A type of sprayed concrete used for rapid tunnel lining, providing support and sealing the excavation face.

Ways shotcrete can fail in a tunnel lining, caused by factors like adhesion, shear, and compression/tension.

Shotcrete with added fibers, making it stronger and more durable, used for long-term stability in tunnels.

A system for classifying rock mass quality based on factors affecting its stability under excavation. Considers factors like rock quality, structural features, and water conditions. Used for predicting tunnel support requirements.

A parameter used in the Q-system to represent the size of an underground excavation and its effect on rock mass stability. It considers the span or diameter of the tunnel/cavern.

A measure in the Q-system that quantifies the reduction in stress around an underground excavation due to its creation, which can influence rock mass stability. Lower SRF indicates greater stress reduction, potentially leading to instability.

The Q-system considers rock quality, structural features (like joint sets and their characteristics), water conditions, and stress conditions to assess a rock mass's stability under excavation.

The number of distinct sets of fractures or joints in the rock mass.

A measure of the roughness of the joint surfaces, where smoother joints are less stable (higher JR means rougher, more stable).

A measure of the degree of weathering or alteration present on the joint surfaces, with higher JA indicating more weathering (weakness).

A factor that considers the impact of water pressure on the strength of the rock mass, especially in joints, affecting its stability.

The Q-System provides an estimate of the rock mass's strength and stability, helping engineers choose appropriate support measures for excavations, tunnels, and other underground structures.