Comparative analysis of common retaining structures in Xining area

Based on the design and construction status of deep excavations and engineering practices of supporting and retaining structures in Xining area in recent years, the mechanism, application scope, design status and shortcomings of 4 kinds of supporting and retaining structures are compared and analyzed for the future research direction. The practices show that when the surrounding environment of excavations allows step-slope, the depth is not more than 12 m, the groundwater level is low and the economic requirements are high, soil-nailing wall should be used as the first choice. When the surrounding environment of excavations allows step-slope, the depth is more than 12 m, the requirements of displacement are strict and the groundwater level is high, composite soil-nailing wall or grillage with prestressed anchors should be used as the first choice. Considering beauty and cost, the grillage with prestressed anchors is better than the composite soil-nailing wall, especially as a permanent support. When the surrounding environment of large complex deep excavations is narrow, the requirements of displacement are strict, the anchorage length or pile diameter selection is limited and the geological conditions are complex, it is more reasonable to choose the combined support of soil-nailing wall at the upper part and anchor pile at the lower part. Finally, combined with the current large complex examples of deep excavations in Xining, the relevant applications are illustrated.