experimental study on pipe strength and field performance of pipe jacking tbm in deep-buried coal mines

To study the strength of steel rebar-reinforced jacking pipes under the loading of deep-buried coal mine strata, this paper proposed a specially designed triaxial pipe loading system and a set of similitude model tests are conducted. the mechanical behaviors of pipes under triaxial loading conditions are analyzed and the configuration parameters of pipe prototypes are determined based on test results. the test results show that the loads are mainly undertaken by concrete rather than steel rebars and the strength of pipes can be increased more efficiently using higher grade concrete. compared with increasing reinforcement ratio, using c60 concrete to fabricate pipes can increasing the ultimate bearing capacity to 2420 kn. the pipe jacking tbm penetrated 138 m in underground coal mine with a buried depth of 600 m and a maximum jacking force of 7042.58 kn. the construction methods and the performance of pipe jacking in deep-buried coal mine are illustrated. the monitoring data of jacking force and deviations are recorded and analyzed. the working experiences obtained from engineering practices are summarized. in addition, the suitability of pipe jacking in underground coal mines is examined