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The low-load one-time construction method of PVC micro-pipe jacking was applied in China and is in its infancy. The small stiffness of the flexible PVC pipe ring leads to the redistribution of soil pressure and the generation of elastic resistance during the jacking process. The jacking force can not be accurately calculated by the existing specifications. The principle and construction method of the PVC micro-pipe jacking method were used to investigate. At the same time, the influence of vertical deformation of PVC pipe on soil arching effect and the additional frictional resistance caused by horizontal deformation were considered based on Terzaghi soil pressure. The corresponding jacking force calculation formula was derived on this basis. Furthermore, the factors that influence the jacking force of PVC pipes were analyzed through finite element numerical simulation. The results indicate that the pressure around the PVC pipe will increase due to the deformation of the pipe. The maximum error between the predicted lower limit and the measured value of the jacking force calculation model proposed is 15%. The measured value is between the predicted upper limit and the lower limit, which proves its applicability. The parametric analysis indicates that the jacking force increases by 1.6 times as the pipe diameter increases by 100 mm and the jacking force increases by about 3 times when the buried depth of the pipeline increases from 4.5 m to 6 m.
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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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