The Ground Movement Problem and Common Misconceptions in a Nutshell
In the US alone, infrastructure damage due to ground movement is estimated at $19 billion annually and growing at a rate of about $0.35 billion/year. This deterioration is caused primarily by strength loss, settlements and swelling/shrinking of the soils constructed beneath foundations and pavements. These ground movements' damage rigid infrastructure such as commercial centers, industrial facilities, roads, residential developments, schools, parking lots, levees, etc.
This historical problem persists primarily because the industry required engineering standards for soil (“fill”) design are essentially never achieved in construction. Fill construction is the only element of infrastructure, where the industry does not achieve design requirements in construction. This condition is largely unrealized in the industry because of assumptions used in design and construction processing, though it is proven by monitoring data on every construction project. Because ground movement often begins developing a few years after construction, there is largely no connection made to this condition as the source of a problem.
Many in the industry assume the earth movement problems come from natural soils well below the construction. However, deeper soils are always well investigated and conservatively managed in design. This management usually includes replacement of upper natural soils and added soils built up above the surface. It is in this new soil construction where the industry makes erroneous assumptions. This is where the primary problems lie. The integrity and stability of our infrastructure foundations and pavements depends on the strength and stability of the soils that we construct beneath, but the industry does not know the strength of fill construction. See the most critical component of ground risk today.
These underlying conditions are most readily visible on most roadways across the country. All roadways are designed and constructed to smooth surface grades, assuming stable soil construction below. However, most road surfaces turn out to be uneven and cracked, with “hills and valleys”, spalls and potholes - all requiring constant maintenance and repair. These conditions generally start developing 2-5 years or so after construction.
A common industry response to the ground problem is to spend more dollars “strengthening” infrastructure construction above the ground, in effort to “bridge over” the unsolved problems in the soil. But this only increases construction costs unnecessarily.