Similar material for small and medium solid-fluid coupled model test and preparation method thereof

The invention discloses a similar material for a small and medium solid-fluid coupled model test and a preparation method thereof. The similar material is prepared from the following raw material components in percentage by weight: 71.7-79.2% of sand, 2.4-8.1% of cement, 2.4-11.0% of kaolin, 2.0-9.0% of vaseline and 4.6-6.7% of water. The preparation method comprises the following steps: weighting the sand, the cement, the kaolin, the vaseline and the water in proportion; stirring the sand, the cement and the kaolin in a stirrer to form a first mixed material, and standing the first mixed material in a room at a temperature of 25 DEG C; uniformly stirring the water and the vaseline in a vessel to form a second mixed material; stirring the first mixed material and the second mixed material at a normal temperature for 3-5 minutes to form a third mixed material, then placing the third mixed material into a forming die, tamping and forming, standing the material at the room temperature for 24 hours after demolding and the like, thereby preparing the similar material. The prepared similar material has the uniaxial compressive strength of 0.3-0.8Mpa, the elastic modulus of 130-223Mpa, the osmotic coefficient of 7.45*10 -9.37*10 cm/s, the cohesive force of 54-87Kpa and the frictional angle of 34-46 degrees and is suitable for simulating the model tests of rocks with different mechanical properties and osmosis.