Abstract: The influencing factors of trackless transportation technology for the Tianping tunnel of ChongqingGuiyang railway are analyzed to realize trackless transportation with nonexplosionproof equipment in tunnels with high gas concentration, ensure the safety of the tunnel construction environment and high efficiency of the transportation machinery, and to pass the tunnel section with high gas concentration smoothly and quickly. Subsequently, the feasibility of the trackless transportation technology with nonexplosionproof equipment is examined, and the corresponding safety risk prevention and controlsupporting techniques are proposed. The applicable results of trackless transportation technology with nonexplosionproof equipment show the following: (1) The gas concentration and outburst volume in the tunnel were reduced effectively, realizing the comprehensive and fullprocess monitoring of gas concentration during the construction process and ensuring the safe implementation of trackless transportation technology with the nonexplosionproof equipment. (2)The comprehensive calculation results of benefits such as labor consumption, equipment input, transportation cost, and schedule show that the construction schedule and cost can be reduced by 5.4 month and more than RMB 30 million, respectively, realizing the safe and highefficient construction of the tunnel with high gas concentration.

Key words: tunnels with high gas concentration, nonexplosion-proof equipment, trackless transportation, risk prevention and control