Abstract: It is introduced the constructing of stamping equipment ribbon trench that is inside a completed factory building and close to its foundation since area confined.On the condition that the maximum depth of stamping equipment ribbon trench is 4.5 m deeper than the workshop foundation,the method of bored piles with prestressed anchors is adopted to ensure the stability of the existing building;and the relevant data on basic testing and acceptance testing of prestressed anchors are also given.