New prefabricated support structure for TBM tunneling in complex strata of coal mines: engineering practice

Tunnel Boring Machines (TBMs) have been successfully applied in the excavation of deep shaft roadways in coal mines, yielding substantial socio-economic benefits. However, technical bottlenecks remain that hinder their further promotion and application. In response to the challenge of current support structures and techniques failing to simultaneously meet the requirements of support efficiency, strength, and construction costs, which impedes the full utilization of TBM speed advantages, a research team has developed a novel steel pipe segment assembly support structure. Large-scale model tests of the new prefabricated support structure were conducted to ascertain the deformation and failure patterns under loaded conditions, and the support structure was optimized based on the test results. Numerical simulations were performed to evaluate the reliability of the new support structure under TBM tunneling conditions. Industrial trials were subsequently conducted to field-test the feasibility of the new steel pipe segment support structure for TBM-excavated roadways in coal mines. The test results indicate that the maximum tensile strain of the surrounding rock is 803 με, and the deformation of the steel pipe support structure is less than 1 mm. The new support structure can be installed quickly, with the installation of one ring of segments (1.5 m) completed within 90 minutes, significantly enhancing the support strength in TBM-excavated roadways and the adaptability to strata conditions. This research provides a technical reference for further increasing the tunneling speed of coal mine roadways and ensuring the continuity of coal mining operations.