(1. State Key Laboratory of Coal Mine Disaster Dynamics and Control，Chongqing University，Chongqing 400044，China；2. State Key Laboratory of Geomechanics and Geotechnical Engineering，Institute of Rock and Soil Mechanics，Chinese Academy of Sciences，Wuhan，Hubei 430071，China)
Abstract：Based on the dimensional analysis method of similarity theory，the similar experimental model was established to simulate the cavity building using the molded salt rock instead of natural salt. By experiments，a kind of molded salt rock that can be used for cavity building was found. Using the self-developed mould，a kind of large-size molded salt rock was obtained，which has a diameter of 300 mm and a maximum height of 500 mm. Three groups of experiments with different kinds of solution mining techniques were conducted，and a method for measuring the cavity shape by saturated brine for its electrical properties was proposed. The study shows that the cavity shape and the cavity building efficiency are affected by the washing techniques，and main factors include the location of casing pipes，location of oil cushion，time of cavity building and water flow. The step-by-step expansion method for cavity building can induce higher cavity building efficiency，and the cavity is an inverted pear-shaped chamber with a volume of 4 200 cm3，the maximum diameter of 24 cm，the average diameter of 20 cm，and the height of 27 cm. The brine concentration is about 22%，which reaches the demand of salt mining. Based on the similarity criteria in the similar experimental model，relationship between model and prototype parameters was developed. It provides a guidance about the design and control of cavity building.
2012, Vol. 31 
