Podcast
Questions and Answers
What primarily causes a slope to become unstable and potentially result in a landslide?
What primarily causes a slope to become unstable and potentially result in a landslide?
- When the slope gradient is zero
- When shear stress is greater than shear strength (correct)
- When shear strength is greater than shear stress
- When there is no rainfall
Which factor is indicated as reducing the cohesion of materials on slopes, making them more susceptible to landslides?
Which factor is indicated as reducing the cohesion of materials on slopes, making them more susceptible to landslides?
- Increased vegetation on slopes
- Heavy rainfall (correct)
- Gradual temperature changes
- The presence of granite rocks
How does shear stress influence the movement of materials on a slope?
How does shear stress influence the movement of materials on a slope?
- It pulls materials downhill due to gravity (correct)
- It increases the friction between soil grains
- It helps to stabilize the slope
- It adds cohesion to the slope materials
What effect does strong weathering have on rocks that can lead to landslides?
What effect does strong weathering have on rocks that can lead to landslides?
Which of the following describes the relationship between slope gradient and shear stress?
Which of the following describes the relationship between slope gradient and shear stress?
What happens to essential services and infrastructure during a landslide in built-up areas?
What happens to essential services and infrastructure during a landslide in built-up areas?
What is the primary consequence of weakened slope materials due to heavy rainfall?
What is the primary consequence of weakened slope materials due to heavy rainfall?
Which component of soil directly affects the force of friction among soil grains?
Which component of soil directly affects the force of friction among soil grains?
What is one primary factor that contributes to landslides in Hong Kong?
What is one primary factor that contributes to landslides in Hong Kong?
At what slope gradient does the risk of landslides significantly increase?
At what slope gradient does the risk of landslides significantly increase?
How do human activities contribute to landslide risks in built-up areas?
How do human activities contribute to landslide risks in built-up areas?
What is a significant consequence of poor maintenance of man-made slopes?
What is a significant consequence of poor maintenance of man-made slopes?
What measure can be taken to prevent landslides from damaging settlements?
What measure can be taken to prevent landslides from damaging settlements?
Which organization is responsible for monitoring and maintaining slopes in Hong Kong?
Which organization is responsible for monitoring and maintaining slopes in Hong Kong?
What is the effect of heavy rain on landslide risks in Hong Kong?
What is the effect of heavy rain on landslide risks in Hong Kong?
Which of the following is a preventive measure that the government has implemented regarding slope management?
Which of the following is a preventive measure that the government has implemented regarding slope management?
What should be done to help people who have lost their homes due to landslides?
What should be done to help people who have lost their homes due to landslides?
How does the removal of vegetation from slopes affect landslide stability?
How does the removal of vegetation from slopes affect landslide stability?
Flashcards
Landslide
Landslide
The collapse of slopes due to gravity, where a mass of soil and rock moves rapidly downhill.
Shear Stress
Shear Stress
The force that pulls materials downhill under the influence of gravity. It is affected by slope gradients and the weight of materials.
Shear Strength
Shear Strength
The force that resists movement down a slope, keeping materials from sliding. It is influenced by cohesion between particles and friction.
Cohesion
Cohesion
Signup and view all the flashcards
Friction
Friction
Signup and view all the flashcards
Slope Failure
Slope Failure
Signup and view all the flashcards
Heavy Rainfall and Landslides
Heavy Rainfall and Landslides
Signup and view all the flashcards
Weathering and Landslides
Weathering and Landslides
Signup and view all the flashcards
What makes Hong Kong's slopes prone to landslides?
What makes Hong Kong's slopes prone to landslides?
Signup and view all the flashcards
How does slope gradient influence landslide risk?
How does slope gradient influence landslide risk?
Signup and view all the flashcards
How do human activities affect landslide risk?
How do human activities affect landslide risk?
Signup and view all the flashcards
How does vegetation affect the stability of slopes?
How does vegetation affect the stability of slopes?
Signup and view all the flashcards
Why is maintenance of man-made slopes essential?
Why is maintenance of man-made slopes essential?
Signup and view all the flashcards
How can barriers prevent landslide damage?
How can barriers prevent landslide damage?
Signup and view all the flashcards
How can we strengthen slopes?
How can we strengthen slopes?
Signup and view all the flashcards
Why is slope monitoring essential?
Why is slope monitoring essential?
Signup and view all the flashcards
How do laws and regulations help prevent landslides?
How do laws and regulations help prevent landslides?
Signup and view all the flashcards
How do landslide warning systems protect people?
How do landslide warning systems protect people?
Signup and view all the flashcards
Study Notes
Landslides in Hong Kong
- Landslides are the rapid movement of soil and rock down a slope due to gravity.
- Approximately 300 landslides occur annually on natural terrain in Hong Kong (60% of the land area).
- Landslides in built-up areas can cause injuries, deaths, damage to buildings and infrastructure (e.g., pipes, powerlines), and disrupt traffic.
Slope Stability
- Slope stability depends on the balance between shear stress (driving force) and shear strength (resisting force).
- Shear stress is influenced by slope angle and weight of materials.
- Shear strength is affected by soil cohesion and friction.
- A stable slope has greater shear strength than shear stress; an unstable slope has greater shear stress than shear strength.
Factors Affecting Landslides
- Heavy Rainfall: Increased rainfall weight increases shear stress and reduces the cohesion and friction of slope materials. Summer months are often high-risk periods.
- Strong Weathering: Weathered rocks (e.g., granite) have lower shear strength, increasing landslide susceptibility.
- Steep Slopes: Larger slope gradients increase shear stress, elevating landslide risk, especially above 30°. Hong Kong's hilly terrain contributes to high risk.
Human Activities and Landslides
- Slope Modification: Cutting and filling slopes for development increases shear stress and reduces stability. Removal of vegetation has similar negative effects.
- Poor Slope Maintenance: Inadequate maintenance of man-made slopes, such as cracked surfaces and improper drainage, reduces shear strength and increases the risk of landslides.
Preventing and Mitigating Landslides
- Barriers: Barriers can be constructed on or at the base of slopes to prevent downward movement in natural terrains.
- Slope Strengthening and Monitoring: Enhancing slope stability, inspecting slopes regularly (like GEO) using instruments, and maintaining records are crucial in managed areas.
- Land Use Regulations: Laws restrict development on steep slopes, need for proper slope studies and government authorization.
- Landslide Warning Systems: The government issues warnings during heavy rain, enabling people to reduce their exposure to potential hazards.
- Public Education and Preparedness: Education programs inform the public about actions to take during warnings. Emergency plans should include well-trained rescue teams, emergency aid, temporary shelters, and financial assistance.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
This quiz explores the phenomenon of landslides in Hong Kong, focusing on their causes, impacts, and the concept of slope stability. Discover the factors that contribute to these natural disasters, including weather conditions and geological properties. Test your knowledge on how these elements interact and influence the safety of the terrain.
