The invention discloses a method for freezing a high-gradient heterogeneous freezing wall. The mixed freezing mode of "
salt water +
liquid nitrogen" is adopted, and a freezing
pipe is arranged at the place where the soil around the shaft needs to be frozen, and a brine freezing
pipe is arranged inside the freezing wall. , and a
liquid nitrogen freezing tube is arranged on the periphery. The
liquid nitrogen freezing tubes are arranged in one row, and the brine freezing tubes are arranged in at least one row, and each row is arranged in a circular shape. When there are two or more rows of brine freezing pipes, the
diameter of the ring in the innermost row should ensure that the temperature of the well side during excavation is not higher than the ideal value that is conducive to the stability of the well side; the brine temperature setting of the brine freezing pipes should ensure that It can form a temperature field that gradually decreases from the inside to the outside. The temperature field formed by the freezing tube
layout method of the present invention has obvious high gradient non-uniformity. Compared with conventional brine freezing, under the same load conditions, the thickness of the frozen wall formed by this
pipe layout is small but has a higher
bearing capacity, which will reduce the amount of
frost heaving and thawing, and reduce the amount of
engineering work for freezing holes , The freezing period is shortened.