Recent Lessons

Show all results for ""

Feature Overview

Ace your exams with our all-in-one platform for creating and sharing quizzes and tests.

Quizzes

Create quizzes and tests automatically from your content using AI.

Flashcards

Automatically turn your notes into digital flashcards.

Share, Export & Embed

Share with classmates or export to Excel and your learning management system.

Stats & Reporting

Auto-grading quizzes and tests with detailed stats and reports.

Mobile Apps

The smarter way to study – wherever you are.

Pricing

Search...

10 Questions

0 Views

Tunneling and Support Systems Problem

Choose a study mode

Play Quiz

Study Flashcards

Spaced Repetition

Chat to lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is a primary reason the connection between surface elements and rock bolts is considered the weakest link in the support system?

It is far from the failure zone.

The surrounding rock is highly stable.

It is close to areas of unsupported rocks. (correct)

Rock bolts are usually too short.

What external factor can affect the integrity of rock bolts apart from the rock joint visibility?

The temperature variations in the rock.

The type of bolt used.

The length of the rock bolt.

Corrosion from ground water. (correct)

What is the effect of high dry shrinkage in shotcrete on construction practices?

It eliminates the need for joint spacings.

It requires closer control-joint spacings. (correct)

It allows for wider joint spacings.

It improves the hardness of the shotcrete.

Why does shrinkage occur in hardened concrete?

From the loss of water during curing. Signup and view all the answers

Which of the following methods can help mitigate tensile stresses in shotcrete?

Adding fibres to the mix. Signup and view all the answers

What defines creep in shotcrete under load?

Time-dependent deformation. Signup and view all the answers

What is a consequence of tensile stresses caused by shrinkage in shotcrete?

Increased risk of cracking. Signup and view all the answers

Which factor does NOT contribute to the weakening of rock bolts in corrosive environments?

Increased tensile strength. Signup and view all the answers

What role does the aggregate type play in the shrinkage of shotcrete?

It can affect the contraction rates. Signup and view all the answers

What condition in shotcrete can cause greater loads on the ground support system?

External deflection and internal warping. Signup and view all the answers

Study Notes

Question 1-1

Connection between surface elements and rock/cable bolts is weakest point in support system.
Tunneling exposes rock in failure zone, making it unstable.
Rock outside failure zone is stable.
Bolts and cables must extend to stable rock to anchor unstable rock.
Locating support structure depth is challenging cause features inside the rock are usually unseen.
Corrosion weakens rock support systems.
Galvanizing and corrosion reducing treatments are needed.
Exposure to aggressive water can lead to pitting, erosion, corrosion fatigue, and fretting.

Question 1-2

Shotcrete shrinkage varies based on water content and aggregate type.
High dry shrinkage requires closer control joints.
Shrinkage causes contraction and tensile stress in hardened concrete.
Cracks form at joints and cause external deflection.
Adding fibers reduces tensile stress.
Creep is time-dependent deformation under load.
Low water-cement ratio reduces creep.
High water-cement ratio increases creep and deflection, leading to collapse risk.
Forces from deflection and rock wall pressure can cause collapse.

Question 2

Rock bolts have two main functions:
Increase beam depth.
Reinforce lamination to reduce interlayer slip.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

Explore the critical aspects of tunneling and support systems in geological conditions. This quiz addresses the challenges posed by surface elements, rock stability, support structure depth, and the effects of corrosion and shrinkage in concrete. Test your knowledge on the connections and materials that play a crucial role in maintaining rock stability and integrity in tunnel construction.