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In the process of tunnel blasting excavation, the influence of ground stress and joints on the blasting effect of rock mass is significant, and they are two important factors that must be considered in the layout of tunnel blasting holes. The static and dynamic mechanical parameters of jointed slate were obtained by indoor experiments by taking the Tongan Expressway Bayue Mountain Tunnel as the engineering background. Based on the LS-PREPOST software, a three-dimensional numerical model of jointed rock mass tunnel blasting under different ground stresses (3 MPa, 6 MPa, and 9 MPa) was established to analyze the distribution of effective stress at different locations after blasting. A method for the layout of blasting hole network in jointed rock mass tunnel under different ground stresses was proposed, and the method was verified based on on-site blasting experiments. The results show that ground stress has a restraining effect on crack propagation during jointed rock mass tunnel blasting, and the greater the ground stress, the more obvious the restraining effect. The explosion stress wave will undergo multiple refractions and reflections at the joint location, leading to serious over-excavation. When the hole spacing of the contour holes in the grade IV rock mass was set to 45 cm and the linear charge density was set to 0.375 kg/m, the average over-excavation value was controlled within 20 cm. The designed concrete volume of the research section was 15.1 m3, and the actual concrete consumption in the three on-site tests was 26.4 m3, 23.7 m3, and 25.8 m3, with an average concrete excess consumption of 10.2 m3 and an average excess consumption rate of 67.5%, which were all controlled within 100%.
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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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