Sandbox test system and method for karst aquifer based on tracer-hydraulic tomography inversion

A sandbox test system for a karst aquifer based on tracer-hydraulic tomography inversion, the sandbox test system comprising:

• a visual sandbox apparatus including a back plate, a front plate, two porous water permeable plates, and a base, the back plate and the front plate being mounted on the base in a parallel manner;
• a water flow control apparatus including two constant water head storage tanks respectively mounted on a left side and a right side of the back plate and the front plate, one of the porous water permeable plates being mounted on the left-side constant water head storage tank, and between the back plate and the front plate, the other porous water permeable plate being mounted on the right-side constant water head storage tank, and between the back plate and the front plate, the back plate, the front plate, the porous water permeable plates, and the base define a sand layer packing space containing a sand layer;
• a karst conduit buried in the sand layer;
• a peristaltic pump;
• a plurality of horizontal wells;
• a data acquisition apparatus;
• and
• a data processing apparatus connected to the data acquisition apparatus, wherein:
• the two constant water head storage tanks are connected to a water supply apparatus that supplies water to the two constant water head storage tanks, so as to control water volumes of the two constant water head storage tanks;
• the front plate is provided with horizontal well mounting holes and tracer adding holes, the plurality of horizontal wells are respectively mounted in the horizontal well mounting holes, and at least one of the horizontal wells is used as a monitoring well, and at least one of the horizontal wells is used as a water injection and pumping well;
• and
• the water injection and pumping well is connected to the peristaltic pump, and the monitoring well is connected to a seepage pressure sensor or an electrical conductivity sensor, the electrical conductivity sensor and the peristaltic pump are connected to the data acquisition apparatus.