Abstract:With the gradual replacement of traditional power lines by underground power pipe trenches, the design of support and excavation of power pipe trench needs to be further studied. Based on the design and construction of power pipe trench along municipal roads in the high-speed railway east urban zone of Xi'an, by sorting out the applicable conditions, advantages and disadvantages of common foundation pit support methods and combined with the specific cases, the summarized conclusion shows that (1) power pipe trenches are often set close to the road red line. The conventional slopping excavation process may have no implementation space. During the design period, the support design should be taken into consideration. (2) In loess regions with sufficient slopping space, the stepped slopping form can be adopted. When the depth of foundation pit reaches 17.2 m, the safety factors still meet the specifications. (3) When there is no space for slopping on site, in light of the stratum characteristics of the loess regions, the priority should be given to the use of soil nail wall support, which is convenient for construction and has better economy. (4) When the cantilever sheet piles are used, the cantilever height should be controlled to be no more than 4 m. When the cantilever height exceeds 4 m, an additional layer of tension anchor rods should be added, which can effectively control the deformation of the steel sheet piles and ensure the safety of the foundation pit.
