On-site monitoring of deep hard rock tunnels can help understand the rockburst characteristics and provide timely warnings. Based on a deep-buried tunnel excavated by TBM, on-site acoustic emission (AE) monitoring was carried out to explore the AE waveforms and parameter characteristics of different sources (rockburst, TBM vibration, rock breaking of cutterhead, rock drilling of anchor drilling machine, etc.) under different AE sensor installation methods (drilling, tunnel wall, grouting anchors, foot anchors, steel bars). The results show that rockburst AE signals are characterized by short duration, high instantaneous energy (though lower total absolute energy than mechanical noise), and a relatively high peak frequency (several tens of kHz). The TBM vibration and excavation signals and rock drilling signals have extremely long duration, extremely high ringing count and absolute energy greater than that of rockburst signals. The rock-breaking signals from the cutterhead and anchor drilling machine are low-frequency signals with a peak frequency of only a few kHz, while the TBM vibration signals have the highest peak frequency (>120 kHz). The ringing count and energy rate slowly increase 10 minutes before rockburst, and there is a short quiet period when approaching rockburst. At the moment of rockburst, the ringing count and energy rate suddenly increase and reach their peak, and various frequency band signals appear, with a large number of low-frequency signals below 10 kHz. The AE b value significantly decreases to around 1.5. The influencing degree of TBM excavation noise on the AE ringing count and energy under different installation methods is in the order of steel bars>anchor rods>tunnel walls>inside the drilling hole, while the peak frequency characteristics are the opposite. AE technology is mainly suitable for rockburst monitoring during TBM shutdown. If drilling conditions cannot be met or more attention is paid to the temporal characteristics of AE parameters, AE sensors can be installed on anchoring structures such as grouting anchors and foot anchors (waveguide rods) to monitor and amplify AE signals. The research results in this study can provide a reference for AE monitoring methods and result analysis of similar deep-buried tunnels excavated by TBM.

Excavated volume is one of the active control parameters of the earth pressure balance shield. In order to examine the influence of excavated volume on shield tunnel construction, and mitigate potential adverse effects from abnormal data, statistical analysis and theoretical derivation of earth pressure balance shield are carried out by analyzing the field excavation data. Research shows that the buried depth of the shield tunnel has no direct influence on the excavation parameters of shield tunneling. The range of the volume coefficient and density coefficient of the excavated soil is obtained. Also, it is concluded that the normal distribution and T estimation method is suitable in the parameter study of the excavated volume in water-rich sandy cobble stratum. At present, the research results of excavated quantity parameters are only applicable to water-rich sandy cobble stratum and composite stratum dominated by sand cobble. Before excavation, the research conclusions can be used to determine the range of excavated volume. During excavation, the proposed research can predict the excavation volume of the excavation ring, and can also predict the excavation soil density of the face. The shield tunneling mode and tunneling parameters can therefore be adjusted in time.