Q151
The primary failure cause in the St. Francis Dam disaster (1928) was related to:
A.
Earthquake
B.
Rainfall-induced landslide
C.
Poor foundation geology
AnswerD.
Overflow erosion
Answer: Option C
Solution
Answer: Option C
Solution:
The St. Francis Dam failed due to unrecognized weak sedimentary rock at the foundation. The left abutment was composed of schist that weakened when saturated, leading to collapse.