Question

The article on the next page from the San Francisco Chronicle, January 27, 1996, describes very serious problems of subsidence, water supply, and environmental pollution that exist today in Mexico City. A stratum of very soft, very high water content clay is the source of most of the settlement that accompanies the pumping of water from the underlying aquifer systems. The clay stratum thickness averaged 79 ft in 1936, and had an average water content of 356 percent. The soil solids have a specific gravity of 2.65. The average settlement of 22 feet during the 60 year period referred to in the newspaper

Answer 1

Answer:

246.3%

the complete question is found in the attached document

Step-by-step explanation:

1st step:

using 1936 data,

w1= 356% = 3.56(356/100) , H= 79 feet

specific gravity = 2.65

Sₓ= 100%= 1

initial void ratio(e₀)= (w1 x specific gravity)/Sₓ

=3.56 x 2.65/1 = 9.434

2nd step

using 1996 data

ΔH= 22ft

ΔH/H = Δe/(1 + e₀)

22/79 = Δe/(1+9.434)

0.278=Δe/10.434

Δe= 0.278 x 10.434

Δe= 2.905

Δe= e₀ - eₓ

eₓ= e₀-Δe

eₓ= 9.434 - 2.905

eₓ= 6.529

3rd step

calculating water content in 1996

eₓ =6.529, specific gravity= 2.65, Sₓ= 100%

W2 X 2.65 = 1 x 6.529

w2 = 6.529/2.65 = 2.463 = 246.3%