foundation protection

huangyhg

foundation protection
there is an existing fence wall with a shallow foundation 300mm. a  drain is to be constucted along the fence line with inverts much lower that the foundation base of the wall. excavation is to commence; how can this be achived without compromising the wall foundation?
thank you

can the drain line be moved the soil influence distance away from the foundation?
i think it depends on how long the wall is.  you can do it in sequence.  maybe use a trencher? may dig 1/6 of the length, put the drain and the slurry (gravel), back fill most of it, and dig some more.  use your engineering judgement on how much you can dig at a time without affacting the wall.  when you dig one side of the wall, think of it as the wall will act like a retaining wall.  i think a trencher/small bucket hoe and a jumping jack will do the job.  what do you think?
bkhenry2,
get your geotechnical consultant on the phone, pronto!
jeff