Marine sediments are characterized by soft texture and low strength, and their strength parameters are closely related to offshore platform pile placement and jacket installation, and are closely related to offshore operation safety. Conventional methods for obtaining strength parameters, such as drilling and cone penetration test, have high cost, few sampling points, and great disturbance to the soil. Therefore, it is of great significance to predict the strength parameters of marine sediments with easily accessible acoustic data. Based on the acoustic propagation theories such as Wood equation, Biot-Stoll model and Dvorkin equivalent medium model, the theoretical P-wave velocity under different physical parameter (density, porosity) gradients was calculated. Combined with the indoor simulated stratum acoustic experiment, the variation characteristics of the calculated and measured sound velocity were compared, and the relationship model between sound velocity and physical parameter was established. The relationship between soil physical parameter and shear strength, cohesive force and other parameters was revealed based on laboratory geotechnical test, and the relationship model between soil physical parameter and strength parameters was established. A prediction model for strength parameters of marine sediments based on acoustic characteristics was established by using physical parameters as bridge. This model not only avoids the problem of water loss disturbance of in-situ sampled soil, but also makes up for the limitation of empirical formula. It has universality and accuracy, and can effectively improve the precision of strength parameters of soil in unsampled areas, improve economic benefits, and play a theoretical guiding role in shallow exploration and development.
| 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 |