Abstract:

The nonexplosive sources are commonlyused in the advance geological prediction of tunnel. The spark source and controllable impact source are used to conduct advance geological prediction test in the Baolin tunnel, to verify the adaptability of the sources and discuss the advantages and disadvantages. The spark source test results show that: (1) The spark source has the advantages of stable excitation and good consistency of takeoff, which is beneficial to the data processing of geological prediction in advance. (2) The spark source will cause more elastic wave than deformation, which has little damage to the surrounding rock. It can be excited in the same excitation hole for many times, which is conducive to the blasting and can effectively ensure the quality of seismic records. (3) In the case of general condition, 40 kJ of spark source is sufficient to meet the demand of seismic wave method for advance geological prediction, and the detection distance can reach 100 m. The controllable shock source test results show that: (1) The shear wave should be used to predict the surface impact source. (2) As a surface impact source, the controllable impact source has controllable energy and convenient transportation, whose energy is 100 times that of hammer source. (3) Under the condition of complete and hard surrounding rocks, the detection distance can reach 100 m.

Key words: spark source, controllable impact source, wave field analysis, tunnel advance geological prediction