The discrete element method (DEM) can analyze the large deformation and large displacement of rock mass effectively, and it is widely used in underground engineering, slope engineering and other fields. However, due to the low accuracy of rock mass structural surface information acquisition, the application of discrete element method in the analysis of jointed rock mass stability is still deviated. In this paper, combined with the advantages of the tunnel seismic prediction (TSP) in obtaining discontinuous geological interface information and the discrete element method in the calculation and analysis of jointed rock mass stability, this paper proposes an advanced analysis method for jointed rock mass stability based on TSP and DEM. Compared to the traditional methods, the analysis results of the jointed rock mass stability are more reliable. Firstly, relying on the advanced detection system — Tunnel Seismic Prediction 203Plus, the unstructured rock mass structure information of the tunnel is obtained, and the spatial attitude of the discontinuous geological interface is further determined. Secondly, based on the Fish programming language, the non-continuous geological interface information can be expressed in the discrete unit software — 3D Distinct Element Code (3DEC). In this way, the excavation calculation model of the tunnels in jointed rock mass can be constructed. Finally, based on the DEM, the excavation of the tunnels in jointed rock mass can be simulated, analyze the stability of surrounding rock during the tunnel excavation process, and realize the stability analysis of surrounding rock stability of jointed rock mass. Based on the Huangjiazhuang Tunnel Project, this paper uses the above method to carry out on-site application. The results show that the location of the dangerous block is predicted to be consistent with the actual exposure of the tunnel surrounding rock based on TSP and DEM, which verify the accuracy and feasibility of this method, and the research results have practical guiding significance for the safe construction of the tunnels in jointed rock mass.

The proportion of large-span tunnels in newly-built highway tunnels is getting higher and higher, revealing the stress release law and deformation characteristics of the tunnel at different excavation steps has important guiding significance for the rational design of the supporting structure parameters. In this paper, a typical section of the Laohushan Tunnel was selected to analyze the stress and deformation response of the large-span tunnel excavated with the semi central diaphragm method (SCDM), with the numerical simulation and field monitoring method. The study found that during the excavation of the large-span tunnel with the SCDM, the stress and deformation response characteristics are different from those ordinary tunnels. Influenced by the settlement of the vault, there was a significant outward expansion tendency, and a high degree of stress concentration in the sidewall. In particular, the supporting structure at the sidewall has a deformation characteristic of expanding outward and then converging inward. In this paper, the in-depth analysis of the stress release law and deformation characteristics of the excavation process of large-span tunnels can provide reference for the excavation and support parameter design of similar projects.

Behavior of rock mass in the intersection between adit and major tunnel is a complicated three-dimensional problem, the increasing support load and additional tunnel deformation may endanger tunnel stability during construction. To understand the deformation behavior of rock mass in the intersection, a 3D numerical analysis was conducted. Comparing the monitoring data, the distribution of the plastic zone, the extrusion displacement of working face and the deformation of the sidewall in the adit and major tunnel were studied. Following analysis results, the distribution and potential influenced area of the intersection in the adit and major tunnel were analyzed. The principle of detection and reinforcement in the intersection were also discussed.