Calculation of shock wave transmission and reflection pressure at the water-soil interface

There is a lack of reliable calculation theory for the transmission and reflection pressure of shock wave at the water-soil interface. Using the mass conservation equation, momentum conservation equation, and the equations of state of water and soil, the Hugoniot relationship and the p-u curve of the propagation of shock wave in water and soil medium are derived, and then the transmission and reflection pressures of the shock wave at the water-soil interface can be analyzed theoretically. Two-dimensional numerical models of the free field in water and water-soil layered medium field are established, in which the water and soil parameters are consistent with those in the three-phase medium saturated soil model used in the theoretical derivation. The calculation results show that the theoretical and numerical solutions of the water-soil interface transmission and reflection pressures are highly consistent. Using 80 g TNT explosives, from the water-soil interface 0.1—0.9 m (proportional burst distance of 0.232—2.089 m/kg1/3) explosion, the theoretical and numerical solutions of the transmission and reflection pressure error is less than 7%, according to the analytical solution of the reflection pressure and the ratio of the incident pressure in the water, the coefficient of the reflection pressure is in the range of 1.6—1.8; from the water-soil interface 0.5 m, the saturated soil containing pressure of the water and soil interface, the reflection pressure coefficient of the water and the water interface, the reflection pressure coefficient of the water and the water interface. At 0.5 m from the water-soil interface, the gas content of the saturated soil varies in the range of 0-10%, and the transmission and reflection pressures are 63.8—70.0 MPa, and the reflection pressure coefficients are in the range of 1.55—1.70 at this time. Derived from the shock wave in the water-soil interface transmission, reflection pressure calculation method, the physical meaning of clear, high precision calculations, can be carried out for the underwater explosion on the submerged soil damage assessment of engineering structures in the soil to provide a theoretical basis.