Indoor model test method for vacuum-membrane-free vacuum pre-compression

The invention relates to an indoor model test method for vacuum-membrane-free vacuum pre-compression. An adopted indoor model comprises a water drainage plate 1, a glass model box 2, a one-way butterfly knot 3, a steel wire hose 4, a steel wire hose supporting tube 7, a steel wire hose main tube 8 and a test soil sample 10, wherein the water drainage plate 1 is inserted into the test soil sample; the water drainage plate is connected to a main tube through the one-way butterfly knot, the hose and the supporting tube; and lower geotechnical cloth 5, mucky clay 6 and upper geotechnical cloth 8 spread on the upper surface of the test soil sample from bottom to top. The test method comprises the following steps of: putting a water-gas separating tank above an electronic scale; connecting the main tube and a vacuum pump to the water-gas separating tank with a vacuum meter; injecting water into the upper geotechnical cloth; opening the vacuum pump to load, observing reading of vacuum pressure of the water-gas separ