Monitoring and Analysis of Pile-anchor Retaining Structure for a Deep Foundation Pit in Beijing

Based on supporting a deep foundation pit by adopting pile-anchor retaining structure.During the constrction,the displacement of pile head,the surface settlement,the axial load of anchor rope are monitored and analyzes the main monitoring data.The results indicate that the pile-anchor retaining structure can control the horizontal displacement of foundation pit and the surface settlement of surrounding structure effectively,and there are some laws in variation of horizontal displacemen and surface settlement.The losses of prestresses of anchors is large,it's about 30%~50%,and the range of variation is about 15% during the constrction;the first anchor rope play an important role in controlling displacement and settlement,the third anchor rope is the key of controlling the maximum bending moment in pile.Giving advice for the design of similar pile-anchor retaining structure combine with the reasons of the calculating data different from the measuring data.