Need information on drain tile pipe

[kmatte]

I am designing a project that involves the use of drain tile pipe. My current specification and drawings show the trench being lined with a geotextile filter fabric and filled with a clean coarse filter aggregate. The pipe is to be placed on two inches of aggregate, and covered with aggregate. The aggregate is then to be wrapped with the fabric.

The contractor has asked if it is allowable to wrap the pipe instead of lining the trench. The soils that I am working with are predominately SC and SM type soils.

Either way there will be some clogging of the fabric. Will the aggregate trap some of the fines before it reaches the fabric and extend the life of the drain, or would it be better to remove the fines before they enter the coarse aggregate.

 

[GeoPaveTraffic]

If you wrap the pipe instead of the trench, you will need to make sure that the aggregate you placing in the trench will serve as a filter for the natural soils. You do not want to loose soil into the trench and cause subsidence problems.

If you are concerned about the functional life of the drain, don't use fabric and use a graded filter instead.