I have a project where we are designing 12 ft high wall in front of a Storm Water detention pond. Due to seasonal water fluctuations the water level at front of the wall will vary. It is also expected at some point 80% of wall in front will have water during peak flow event.
I wall be using a heavier dry cast block in conjunction with Polyester Geogrid Strata or Mirafi. My question wrt to reinforced infill what is the best type of infill i should be using. Well graded granular with 35% fines or limiting only 5% to 10% fines.
I am going to use lots of drainage outlet points
In my external analysis i will be accounting for Hydrostatic pressure just be conservatively safe and recommending geogrid length accordingly (base to height ratio 80%H to 100%H).
For my internal stability analysis i will assume since the reinforced is free draining gravel with frequent outlet points hydrostatic pressure will not be an issue.
Contractor is suggesting to use 57 stone (clear stone wrapped in filter fabric) for the entire gegorid zone since he thinks he will have to put a blanket,face & chimney drain anyway due to water conditions.
He is ok with cost of clean stone & additional geogrid length due to light weight of stone but he wants to stick with 1 material in reinforced zone. The additional benefit he says is that he will not need to compact it since the material is self compacting.
My issue is due to unit weight difference between block facing (approx 145pcf) & 57 stone (118 pcf) the entire MSE wall structure will not act as a coherent mass. I also feel some %age of fines as found in well graded granular soils is helpful to provide adhesion to polyester geogrids. The Gegorids & Clear stone does not give you strong interlock (binding) as Graded Granular material. Even though, foundation soil can be controlled to limit differential settlement the MSE structure will be a weak and prone to movements. The situation is almost like concrete without fine aggregates.
Please provide suggestions.
Thanks.
I wall be using a heavier dry cast block in conjunction with Polyester Geogrid Strata or Mirafi. My question wrt to reinforced infill what is the best type of infill i should be using. Well graded granular with 35% fines or limiting only 5% to 10% fines.
I am going to use lots of drainage outlet points
In my external analysis i will be accounting for Hydrostatic pressure just be conservatively safe and recommending geogrid length accordingly (base to height ratio 80%H to 100%H).
For my internal stability analysis i will assume since the reinforced is free draining gravel with frequent outlet points hydrostatic pressure will not be an issue.
Contractor is suggesting to use 57 stone (clear stone wrapped in filter fabric) for the entire gegorid zone since he thinks he will have to put a blanket,face & chimney drain anyway due to water conditions.
He is ok with cost of clean stone & additional geogrid length due to light weight of stone but he wants to stick with 1 material in reinforced zone. The additional benefit he says is that he will not need to compact it since the material is self compacting.
My issue is due to unit weight difference between block facing (approx 145pcf) & 57 stone (118 pcf) the entire MSE wall structure will not act as a coherent mass. I also feel some %age of fines as found in well graded granular soils is helpful to provide adhesion to polyester geogrids. The Gegorids & Clear stone does not give you strong interlock (binding) as Graded Granular material. Even though, foundation soil can be controlled to limit differential settlement the MSE structure will be a weak and prone to movements. The situation is almost like concrete without fine aggregates.
Please provide suggestions.
Thanks.
