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May 12

May 12, 2015 Update

Posted on May 12, 2015 at 10:26 AM by Saja Aures

Now that the majority of utility lines have been relocated, crews have begun the first steps towards surcharging the existing unsuitable subsoil.  “Surcharging” is required on this project due to the unsuitable nature of the underlying soils found along the majority of the project.  The existing subsoil consist of soft clays and a large amount of organic matter.  If these soils are not properly surcharged, long term settlement of the new roadway and utility lines could be at stake.  Surcharging of these soils involves undercutting the first five feet of material, placing geotextile fabric along the bottom of the trench and then backfilling with suitable soils.  Next wick drains will be installed approximately 40’ vertically into the ground.  Wick drains are not always required to accomplish surcharging of unsuitable underlying soils, but will accelerate the surcharging process.  The addition of wick drains with surcharging will allow the process to occur in six months versus potentially a year and a half or two years.  Once wick drains are installed, then suitable soils will continue to be built up on the surface (above proposed final grades).  The combination of wick drains and the weight of soil over the unsuitable subsoil will force moisture out of the underlying soils, consolidating this unsuitable material.  This surcharging affect will result in predicted settlement over a six month period.  This settlement over a six month period will prevent the underlying unsuitable soils from settling gradually over a long period of time.  Surcharging efforts have begun along the new alignment of General McIntosh Boulevard as well as along the south side of President Street closest to town.  These efforts will continue over the next few months. 

A second crew continues to make progress on the south side of President Street by installing the new 8” water main, manholes, valves, and fire hydrants.  Once these lines are installed, this crew will mobilize to General McIntosh and Randolph Street to continue new utility line installation of water, sewer, and storm drainage lines in this location.

As mentioned in previous posts, a third crew continues to work along the south side of President Street (either side of the Truman Parkway) installing steel casing beneath the railroad tracks found in this area of the project.  Installation of these steel casing will allow utility crews to run future water, sewer, and gas mains beneath these tracks without damaging the tracks or interruption of train operations along the tracks. 

An additional fourth crew will be mobilizing to the site this week to begin installation of water and sewer utility lines on the far east end of the project (along the south side of President St., both sides of Truman Parkway). 

Rain during previous weeks has delayed the paving contractor, but he hopes to be back on schedule this week to pave Randolph Street (just south of President Street).