Geotechnical Flashcards
7 cards from real BCE practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Geotechnical flashcards as text
What is the primary purpose of a consolidation test (oedometer test) in geotechnical engineering?
Answer: Determine compressibility and rate of consolidation of cohesive soils
The oedometer test measures how much a saturated cohesive soil compresses under load and how quickly excess pore pressure dissipates.
Which of the following best describes the coefficient of consolidation (Cv)?
Answer: Parameter combining permeability and compressibility that governs consolidation rate
Cv = k/(mv·γw), combining hydraulic conductivity and volume compressibility to describe how fast consolidation proceeds.
A soil has a liquid limit of 60% and a plastic limit of 30%. What is the plasticity index?
Answer: 30%
Plasticity Index (PI) = Liquid Limit − Plastic Limit = 60 − 30 = 30%.
In Terzaghi's bearing capacity equation for a strip footing, which factor accounts for the depth of embedment?
Answer: Nq
Nq is the bearing capacity factor associated with the surcharge term (q = γDf), which represents the overburden pressure from footing embedment depth.
What type of failure surface does Rankine's earth pressure theory assume?
Answer: Planar (straight line) slip surface
Rankine's theory assumes a planar failure surface inclined at 45 + φ/2 degrees from horizontal for active conditions.
Which in-situ test provides continuous soil profiling by measuring cone resistance (qc) and sleeve friction (fs)?
Answer: Cone Penetration Test (CPT)
The CPT pushes an instrumented cone into the ground at a constant rate, continuously recording qc and fs to classify soil layers.
What does a negative value of the pore pressure parameter B indicate in a triaxial test?
Answer: Partially saturated or dilative soil behavior
B < 1 indicates partial saturation or dilative dense sand behavior where pore pressure decreases under shear.