## 4 Parametric Analysis
#### 4.2.2 The Influence of Different Support Channels  
To explore the influence of the number of supporting lanes of deep and large foundation pits on the deformation of adjacent existing subway stations and tracks, five working conditions of three, four, five, six and seven supporting lanes were set for foundation pit excavation simulation. The maximum deformation curves of the station and track structures under various conditions are shown in Figure 28.  
The maximum vertical deformation of the station and track structure decreases with the increase in the number of interbracing channels. When the interbracing of the foundation pit increases from four to seven, the deformation of the maximum vertical displacement of the station and track structure is no longer significantly increased. The maximum vertical deformation of the station is between 1.82 and 4.10 mm, and the maximum deformation of the track is between 1.64 and 3.51 mm. Compared with the deformation of the station and track under the influence of foundation pit construction of three interbracings and one anchor cable support system, when the foundation pit adopts four interbracings, the maximum vertical displacement of the station and track structure deformation is reduced by 21% and 24%, respectively. When five interbracings are adopted, the maximum vertical displacement deformation decreases by 24% and 22%; when six interbracings are adopted, the maximum vertical displacement deformation decreases by 30% and 29%; when seven interbracings are adopted, the maximum vertical displacement deformation decreases by 30% and 24%.  
The maximum horizontal deformation of the station and track structure decreases with the increase in the number of interbracings. The maximum horizontal deformation of the station is between 2.28 and 4.68 mm, and the maximum deformation of the track structure is between 1.97 and 4.21 mm. The horizontal displacement deformation of the station and track structure is sensitive to the number of supporting paths in the foundation pit. Compared with the three interbracings and one anchor cable support structure of the foundation pit, when the foundation pit adopts four interbracings, the maximum horizontal displacement deformation of the station and track structure is reduced by 12% and 20%, respectively. When the foundation pit adopts five interbracings, the maximum horizontal displacement deformation is reduced by 17% and 18%, respectively. When the foundation pit adopts six interbracings, the maximum horizontal displacement deformation is reduced  
Figure 28: Maximum vertical and horizontal deformation values of stations and tracks under different numbers of interbracings.  
by 18% and 15%, respectively. When the foundation pit adopts seven interbracings, the maximum horizontal displacement deformation is reduced by 24% and 28%, respectively.  
The deformation of the station and track is greatly affected by the number of interbracings in the foundation pit. When the number of interbracing paths is greater than four, the maximum vertical displacement decreases less, and the maximum deformation of the station and track changes by approximately 20% compared with the three interbracings and one anchor cable support system. Considering the economic cost of construction, three interbracings and one cable support system can be selected for foundation pit support design, but further protective measures should be taken for foundation pits and station structures.