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To explore the stress and deformation characteristics of an existing tunnel caused by foundation pit dewatering, a threedimensional numerical model was established based on an actual project. Taking the maximum vertical displacement of the tunnel as the evaluation index, an orthogonal table is used to screen the optimal combination and the main influencing factors. Then, the main influencing factors are analyzed via univariate analysis to study the stress and deformation law of the tunnel. The results of the range and variance analyses showed that the insertion depth of the diaphragm wall was the main factor affecting the maximum vertical displacement of the tunnel outside the pit. Therefore, when a new foundation pit project adjacent to an existing tunnel has a dewatering demand, this factor can be selected first to control tunnel deformation. As the insertion depth of the diaphragm wall increases, the bending moment and deformation of the tunnel decrease. After the insertion depth of the diaphragm wall reaches a soil layer with poor water permeability, the tunnel deformation decreases significantly. At this time, the deformation of the tunnel can be effectively controlled; however, controlling the deformation of the tunnel by increasing the insertion depth is of little significance. The dewatering causes the adjacent tunnel outside the pit to produce "horizontal duck egg" settlement deformation toward the pit, obliquely downward, and the deformation of the tunnel vault and the side arch waist of the adjacent foundation pit should be emphasized during the construction process.
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| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |
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