Differential Analysis and Prediction Optimization of Ground Surface Settlement Induced by Quasi-Rectangular Shield and Pipe Jacking Tunnelling

Table 3

The critical ground loss ratio of different tunnel depths [24].

Axis buried depth Z (m)	Width coefficient of settlement trough i (m)	Critical ground loss rate (%)	Critical ground loss rate (%)
6	3.29	0.344	0.194
7	3.73	0.389	0.214
8	4.15	0.433	0.233
9	4.56	0.476	0.253
10	4.96	0.518	0.273
11	5.35	0.559	0.292
12	5.73	0.599	0.311
13	6.11	0.639	0.330
14	6.49	0.678	0.349
15	6.86	0.716	0.367