High water table
High water table
(OP)
I have parking area under construction, the water table is high, about 1 m deep , the compacting machines sinking about 25 cm when operated in the area , and the water is going to the surface ,, any advice,,





RE: High water table
You don't mention the type of compaction equipment, but don't use rubber-tire equipment and don't use vibratory. Use steel wheel static compaction for this condition. If clayey soils, use static sheepsfoot compactor. In either case, use more passes with lighter compactor.
RE: High water table
RE: High water table
Sometimes it is possible to stabilize the situation using rock fill that we call 3" clear, the same stuff as breaker run, but with no fines below the 3 inch size. In this case this is placed over the unstable area and compacted into the lower mushy material and the fines are driven into the voids of this rocky fill. With enough of the rock, things stabilize since all loads are carried rock to rock.
When it comes to design, however, I consider any stabilizing layer as just subgrade, not base course material.
There are other treatments that may be considered, such as stabilizing with lime or old cement.
RE: High water table
Run these drains into a solid pipe then lay the solid pipe into a drainage structure (inlet) outfall etc.
Then I would begin with subgrade treatment, base, and surface layers.
Vibratory equipment is only bring the water to the top I would suspect.
........or you could raise the elev. of your parking area(s)
RE: High water table
So, for placing base over a weak subgrade (assuming you have to and the schedule won't permit delays), I call for undercut at all storm inlets, and other grade fixing details. In the rest of the area I play with grades with a thicker than standard base course. The thickness of undercut as well as final base course is determined in the next step shown here.
This is determined by placing a test area tapered thickness of base course over a typical unstable subgrade area. Thickness varies from the design thickness to maybe twice that thickness.
Then drive fully loaded trucks over the tapered thickness test area. Where you find no "significant" ruts develop in the base surface, then chose a base course thickness somewhat above that and go with it on the job.
Adjust grades and slopes accordingly.
This tapered test area procedure also can be used to find the thickness of 3" clear or other treatment needed for upgrading the subgrade you are trying to fix.
I've used this procedure a lot and find it is accepted by owners especially when time is critical.