This invention provides a pump pit structure, an underground water-sealed cavern, and a construction method for the underground water-sealed cavern, belonging to the technical field of underground water-sealed caverns. The pump pit structure includes a top-opening
water collection trough and an oil collection trough. The
water collection trough includes a sloping trough and a main trough; the sloping trough is connected to the main trough along a downward slope. The oil collection trough is located within the main trough, with its top higher than the top of the
water collection trough. By designing the pump pit as a sloping trough and a main trough, the
effective volume of the pump pit is divided into two parts. The sloping trough gently slopes downwards along the cavern floor, reducing the vertical wall excavation height of the pump pit while providing most of the
effective volume, ensuring efficient and normal operation of the underground water-sealed cavern throughout its entire
operating cycle. The main trough is located at the bottom of the sloping trough, with a depth meeting the height requirements of submersible pumps and submersible oil pumps. Compared to traditional pump pits, this design reduces the width of the deepest vertical excavation, lowering the excavation
workload and construction difficulty of vertical pump pits.