Posted By Pete Sutton Your right in that ground conditions are the most significant factor. General rule of thumb for good ground is 1m or waist height on an average person

Posted By laugar I agree paul you Need to support excavations where their is a risk if collapse, a risk assessment should highlight the risk such as the affects of weather rain frost traffic movement in and around the excavation and length of time left open

Posted By peter gotch Hi Mark Yes depends on ground conditions. In hard rock you could have a 6m sheer excavation with zero chance of collapse - effectively lots of these on the railway line South of Inverness. Conversely, in gravelly ground, collapse readily foreseeable with depths of much less than 1m and with the potential for someone to be trapped e.g. if kneeling down to joint pipes in a trench. Regards, Peter

Posted By Luke. As someone one that works in ground works... Each excavation will have to be assessed prior to starting by a competent person. They will decide the best course of action i.e. battering back (advice can be found in HSG185), stepping or shoring. As far as inspections go, the previous comment on 7 days etc.. is correct. There have been people killed in excavations less than 1m again, risk assess the ground conditions. When it comes to ground works you can not have a general rule. .... it will be interesting to see what the revised version of HSG185 stipulates when it is released.