CURRENT STATUS AND FUTURE TRENDS OF STUDIES ON PREDICTION AND CONTROL OF SUBSIDENCE IN ROCK SALT CAVERNS

The construction of the underground petroleum and gas storage caverns in rock salt has become the direction of the energy reserve development. However,the study on the subsidence in the region of underground storage caverns is still in the state of exploration. Disasters induced by the subsidence happened from time to time. So it is necessary to investigate the subsidence in the region of underground storage caverns in rock salt.The investigation will provide reliable principles for the design and construction. This paper reports the authors literature reviews on the processes and the results in forecast of the subsidence in the region of underground storage caverns obtained by scholars in China and aboard. Three aspects are summarized as follows: 1)insitu monitoring: France,German,and American have established the insitu monitoring net successively,and got a large number of monitoring data; 2)theoretical calculation: the scholars in China introduced the random medium theory to the forecast of subsidence induced by the water mining in rock salt in the late 20th century,which provided a new theoretic basis for the forecast of the subsidence in the region of underground storages; 3)numerical simulation: the scholars in Europe made use of FLAC2D program to simulate the ground stability in the region of the storages in rock salt,and the scholar in China made use of the forecasting model established on the basis of new probability integral 3D model to simulate the subsidence successfully. Besides,in order to control the ground deformation in the region of storages effectively,the pillar supported mining methods have been applied extensively in the construction of underground storages in rock salt in some foreign countries. At last,this paper puts forward that further studies will focuses on the time dependent ground deformation,revise the theoretic model properly,and improve the parameter choosing method with considering the in situ monitoring data. Consequently,it is expected to get more reliable and veracious forecasting result．