Model test device for subway shield tunnel underneath passing existing tunnel in soft soil area

The invention relates to a model test device for a subway shield tunnel underneath and parallelly passing an existing tunnel in a soft soil area. The invention aims to provide the model test device for a subway shield tunnel underneath and parallelly passing the existing tunnel in the soft soil area, and the device is simple in structure, convenient to manufacture and simple and convenient to operate. The device is provided with a model box, one or more columns of vertically-arranged starting holes capable of being opened and closed are formed in an end face of one end of the model box, and one or more columns of vertically-arranged receiving holes capable of being opened and closed are formed in an end face of another end of the model box; the model box is filled with soft soil, a shieldtunnel model I serving as the existing tunnel is arranged in the soft soil, and the shield tunnel model I extends to the receiving holes from the starting holes; a shield tunnel model II is arranged in the model box and below