Multi-section active switch type in-situ heat conduction soil electric heating device and heating method

The invention discloses a multi-section active switch type in-situ heat conduction soil electric heating device and a heating method.The multi-section active switch type in-situ heat conduction soil electric heating device comprises a power supply system arranged above the ground and a heating system penetrating into the ground, and the heating system comprises a heating well and a heating assembly arranged in the heating well; the heating assembly comprises a spiral coil heating resistor and a plurality of vertical conductive connecting rods, and different conductive connecting rods are connected to different depths of the spiral coil heating resistor; the power supply system and the spiral coil heating resistor are communicated with any two conductive connecting rods through a control circuit to form a closed-loop circuit to realize heating of the spiral coil heating resistor at different depth sections, and the control circuit is provided with a switch for controlling on and off of different closed-loop ci