Circular orbit type drilling equipment and drilling method

According to the circular orbit type drilling equipment and the drilling method, rotation operation of the telescopic arm is replaced by annular orbit operation, and the span of the telescopic arm can be greatly shortened. The well drilling equipment comprises a main machine, an open caisson wall, a lifting unit and a well wall lowering unit used for lowering the open caisson wall. The main machine comprises a track beam, a power unit, an annular track and a deslagging unit; the rail beam is in sliding fit with the well wall of the open caisson; an annular track is arranged on the lower end surface of the track beam; the power unit is mounted on the annular track; the power unit comprises a power head, a telescopic arm and a drilling tool; the power head can move along the annular track, the fixed end of the telescopic arm is in pin joint with the power head, and the drilling tool is installed at the end of the telescopic end of the telescopic arm. The telescopic arm can swing around a pin shaft, which is in