In order to further explore the pipe-soil interaction and the failure mechanism of buried pipelines during the collapse process, the element birth and death technology and the displacement load technology were used to simulate the soil collapse process. The coupling models considering the pipe-soil nonlinear effect were constructed respectively to analyze the failure law of buried pipelines under collapse. The results show that the bottom of the pipe jacking is the control point, the axial stress is the control stress, and the junction of the non-subsidence area and the subsidence area and the center of the subsidence area are dangerous sections. Applying displacement load technology to element birth and death technology, the location of the most dangerous section transitions from the junction of non-subsidence area and subsidence area to the center of subsidence area, and the peak value of Von-Mises stress increases from 4.3 MPa to 6.09 MPa. The application of displacement load technology makes the lower part of the pipeline always in contact with the soil, and the pipeline is subjected to strong shear near the junction of the non-subsidence area and the subsidence area. The element birth and death technology is lost with the soil, and the pipe-soil state gradually changes from contact to separation, which is a weak shear effect. The Von-Mises stress peak is larger and the radial stress is smaller, which can better reflect the actual situation. According to the stress and settlement values, the maximum Von-Mises stress prediction formula is fitted, and the error is within 7%. The research results can provide reference for the safe operation of pipelines and the selection of collapse simulation methods.
| 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 |