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Soil Testing Indiana

## CPT Dictionary: Overburden Stress

Overburden stress, also called vertical stress or overburden pressure, is the pressure imposed on a layer of soil by the weight of the layers on top of it. Overburden stress can cause errors or drift in CPT measurements, creating the need for correction factors in deeper tests depths and soft or fine-grained soils. However, overburden stress is also useful in determining the soil’s mechanical properties. In this blog, we’ll give an overview of the effect of overburden stress on CPT testing and what we can learn from it. The formula for overburden stress is given by: σvo = overburden stress ɤi = in situ density of soil layer hi = height of soil layer If it’s been a while since you’ve seen summation notation, this means that for each soil layer, you multiply the density of the layer by its height, then add all the resulting weights together until the pressure at the desired depth is known. In practice, the exact height and density of the soil layers at the test site are usually not known, so you may have to determine an average density based on what you do know about the geology of the area. CPT measurements of tip resistance, sleeve friction and pore pressure tend to increase along with increasing depth and increasing overburden stress. This effect can be seen in the graph at right. For this reason, we correct for overburden stress in calculating the normalized friction ratio and normalized tip resistance: to ensure that your data is consistent, it is important to use these parameters in deep tests and in soft, fine-grained soils, as we discussed in an earlier blog. In addition to normalized CPT parameters, overburden pressure allows us to understand and calculate the following engineering parameters: Effective overburden stress: the effective stress on [...]

## I-65 construction south of Indy tests commuters’ patience

Trips from Southport to southern Johnson County can take up to an hour longer Story Highlights More than \$286M in road projects from Indy to Louisville on I-65 this summer. 20 motorists have died in accidents on I-65 this year Southside commuters are swerving, merging and yielding a lot for road construction this summer — and there’s little relief in sight. From Southport Road to Edinburgh and beyond, concrete testing barricades and orange traffic barrels on Interstate 65 have led drivers through myriad lane shifts and closures, adding precious time to rush-hour commutes, as the highway and bridges are rebuilt or repaired. Alternative routes, including portions of U.S. 31, also are being revamped. “There aren’t too many areas (of I-65) where we don’t have construction testing and inspection going on right now,” said Indiana Department of Transportation spokesman Harry Maginity. “If you are driving from Indianapolis to Louisville (Ky.), you are going to see a lot of it all year.” INDIANAPOLIS STAR I-65 NB lanes reopen in Lafayette area The biggest projects are on I-65 around Greenwood where about 63,000 cars travel both ways each day. Heavy machinery in the blocked-off medians and on bridges has made space in the travel lanes tight and twisting. Combined with reduced speeds, the journey in and out of Indianapolis can add more than hour of travel time for a trip between Southport and Edinburgh. “Our drivers plan that a trip from I-465 on the Southside to Edinburgh is going to be 45 minutes slower,” said Tim Piper, owner of Same Day Transportation, Indianapolis, which has 35 trucks. “If there’s an accident, it’s going to be even longer.” Overall, INDOT Construction Testing is doing three repair projects worth a combined \$156 million on I-65 in the metro area. Four other projects to the Kentucky [...]

## Percolation test

Testing method A percolation test consists of digging one or more holes in the soil of the proposed leach field to a specified depth, presoaking the holes by maintaining a high water level in the holes, then running the test by filling the holes to a specific level and timing the drop of the water level as the water percolates into the surrounding soil. There are various empirical formulae for determining the required size of a leach field based on the size of facility, the percolation test results, and other parameters. For leach line testing, a minimum of three test holes are drilled, most commonly six to eight inches in diameter. Ideally, these should be drilled to different depths from three to six feet below the surface. For better, more conclusive results, five drill holes are used in a pattern of one hole at each corner of the proposed leach field and one test hole in the center. Testing of these holes will result in a value with units of minutes per inch. This value is then correlated to a predetermined county health code to establish the exact size of the leach field. Testing for horizontal pits typically requires five to eight test holes drilled in a straight line, or along a common contour, from three to ten feet below the surface. Testing is identical to leach line testing, though the end result is a different type of septic system, established through a different calculation. Vertical seepage pits are slightly different in testing methods due to their large size, but the basic testing method is essentially the same. A hole, typically three to four feet in diameter is drilled to a depth of twenty or thirty feet (depending on the local groundwater table), and a fire hose is used to [...]

## California highway landslide leaves vehicles buried – video

Aerial footage shows work crews clearing mud and debris following flash floods that left nearly 200 vehicles stuck in up to 5ft (1.5 metres) of mud. The Leona Valley, about 20 miles north of Los Angeles, saw extensive downpours on Thursday, with 3.58 inches (9 cm) of rainfall during a 30 minute period. Elsewhere in southern California, several roads were washed out and there were reports of motorists having to be rescued from torrential flooding

## Pence signs bill repealing Indiana construction wage law

A Republican-backed measure that will repeal Indiana's law setting wages for state and local government construction projects has been approved by Gov. Mike Pence. INDIANAPOLIS (AP) - Pence signs repeal of IN construction wage law A Republican-backed measure that will repeal Indiana's law setting wages for state and local government construction projects has been approved by Gov. Mike Pence. Pence signed the legislation Wednesday and says it will allow the free market to determine pay scales rather than government boards. Supporters estimate the change will reduce project costs by as much as 20 percent by allowing more contractors to pay wages below union scale. Opponents dispute such savings will occur and say it will open the door for low-paying, out-of-state contractors. The measure sparked controversy during this year's legislative session, including a rally that brought thousands of contractors and union members to the Statehouse lawn in April. The repeal takes effect in July.