Application and monitoring analysis of combined supporting system by prestressed anchors and soil nails for a deep excavation in Lanzhou

Taking a deep excavation of Gansu Co., Ltd. of China Mobile Group as an example, the application of combined supporting system by soil nails with single-row and double-row prestressed anchors in deep excavations with complex soil strata in Lanzhou is introduced. The key construction technology is also discussed. The engineering application effect shows that the design scheme for the support is reasonable, the effectiveness is good and the requirements of design and environment are satisfied. The monitoring results show that the deformation of deep excavation as well as the change rate of vertical settlement of the slope can be effectively controlled by the prestressed anchors. The effect of applying double-row prestressed anchors is better than that of single-row prestressed anchors. The experience gained from this project plays a guiding role in the similar projects in Lanzhou.