Pipe section foundation of large-scale immersed pipe tunnel

The utility model discloses a pipe section foundation of a large-scale immersed pipe tunnel, comprising an immersed pipe tunnel pipe section foundation trench with an inverted trapezoidal section, wherein a rubble subbase, a gravel secondary substrate and a bentonite mortar grouting layer are orderly arranged at the bottom of the immersed pipe tunnel pipe section foundation trench from bottom upwards, wherein the rubble subbase is 40 cm thick, while the gravel secondary substrate is 20 cm thick and the bentonite mortar grouting layer is 40 cm thick. The rubble subbase is formed by adopting 80-150 mm secondary rubbles; the gravel secondary substrate is formed by adopting 20-80 mm graded gravels; and the bottom surface of the immersed pipe tunnel pipe section foundation trench is 20.43 m to 23.2 m away from the water line. The pipe section foundation of the large-scale immersed pipe tunnel provided by the utility model is capable of reducing the construction cost and also capable of satisfying the structural characteristics of the immersed pipe tunnel; the settlement deformation is stable and the accumulated settlement amount is tiny; therefore, maximum benefit of the construction quantity of the immersed pipe tunnel foundation can be guaranteed to be realized.