Application of Composite Soil Nailing Structure in Foundation Pit Supporting

Soil nailing supporting technology is applied widely in China, soil nailing and prestressed anchor cable combined is a new composite soil nailing structure for foundation pit supporting, and there are more advantages, but many key issues require to be studied further. In present, the perfect standard of the design and the calculation and the construction control can not be determined for the supporting structure. The mechanism of supporting technology and the cause of destruction were analyzed in the paper. The key problem was that horizontal displacement of the structure was controlled for the safety of composite soil nailing structure. According to a composite soil nailing supporting in foundation pit, horizontal displacement of pile body was measured by reasonable measuring point. Some conclusions were drawn by displacement curves: horizontal displacement was progressive and sensitive to upper several layers digging, and was affected greatly by upper two layers, anchor cables arranged in upper layers were advantageous to reducing deformation of foundation pit slope, horizontal displacement of supporting structure was affected obviously by structure dimension. According to field test of soil nailings and prestressed anchor cables, the conclusions were drawn that horizontal displacement was affected by them.