Geotechnical Engineering & Risk Assessment Flashcards

What is the primary objective of geotechnical engineering?

Answer: Analyzing soil & rock for structures

Geotechnical engineering is a branch of civil engineering that deals with the behavior of earth materials, specifically soil and rock, and their application to engineering design. Its primary objective is to investigate and analyze the properties of these materials to ensure the safe and stable design and construction of foundations, retaining walls, and other structures.

What test is commonly used to determine soil shear strength?

Answer: Direct shear test

The direct shear test is a common laboratory test used in geotechnical engineering to determine the shear strength parameters (cohesion and angle of internal friction) of soil. It involves applying a normal load to a soil sample and then shearing it along a predefined plane, measuring the shear force required to cause failure.

What does the standard penetration test (SPT) measure?

Answer: Soil penetration resistance

The Standard Penetration Test (SPT) is an in-situ test widely used in geotechnical investigations to assess the density and consistency of granular soils and the stiffness of cohesive soils. It measures the resistance of the soil to the penetration of a standard sampler driven by a hammer, providing an N-value that correlates to soil strength.

What is liquefaction in geotechnical risk assessment?

Answer: Loss of soil strength during shaking

Liquefaction is a phenomenon where saturated, loose granular soils temporarily lose a substantial portion of their strength and stiffness, behaving like a liquid, due to the rapid increase in pore water pressure caused by earthquake shaking. This loss of strength can lead to severe ground deformation and structural damage.

What role does slope stability analysis play?

Answer: Assess landslide risk

Slope stability analysis is a geotechnical engineering process used to evaluate the potential for a natural or engineered slope to fail, primarily through landslides. It involves analyzing factors like soil properties, groundwater conditions, and external forces to determine the stability of a slope and assess the associated risks.

Why is foundation design critical in geotechnical engineering?

Answer: To ensure stability and safety

Foundation design is critical in geotechnical engineering to ensure the stability and safety of structures. Geotechnical engineers analyze soil and rock properties to design foundations that can safely support the imposed loads without excessive settlement, tilting, or catastrophic failure. Proper design prevents structural damage, ensures long-term performance, and protects human lives.

What is the significance of soil permeability testing?

Answer: Water flow measurement

Soil permeability testing is significant because it directly measures the rate at which water can flow through a soil sample. This property is crucial for various geotechnical and environmental applications, such as designing drainage systems, assessing groundwater movement, and evaluating the suitability of soil for waste containment or irrigation. Understanding permeability helps predict how water will interact with the ground in different engineering contexts.

What is the purpose of a risk assessment in geotechnical engineering?

Answer: Identify and mitigate hazards

The purpose of a risk assessment in geotechnical engineering is to systematically identify potential geological and geotechnical hazards, such as landslides, excessive settlement, or liquefaction. Once identified, engineers can then develop strategies and design solutions to mitigate these risks. This proactive approach ensures the safety, stability, and long-term performance of civil engineering projects and protects public safety.

What is a retaining wall used for in geotechnical engineering?

Answer: Stabilize slopes and prevent erosion

A retaining wall is a structure used in geotechnical engineering to hold back soil or rock from a slope that would otherwise collapse or erode. Its primary purpose is to stabilize slopes, prevent soil erosion, and create usable land on uneven terrain. By counteracting lateral earth pressure, retaining walls ensure the stability of elevated ground surfaces for construction or landscaping.