ive dug some trenches for foundations but have got loads of clay drainage pipe all over the place. i was thinking i could just put some spanlites, maybe dig into the clay either side and have them rest on some concrete commons. but then i googled it and now im not sure whether i have to shutter the whole pipe as well. its trenchfill. got the BI coming on monday so would rather do it sunday if i have to. any advice would be appreciated.