Research On High Performance Shotcrete By Wet-Mix Method And Support For Single-Layer Tunnel Lining

The high performance concrete(HPC) has been widely used in projects such as high-rise buildings, roads, Bridges, nuclear power, and obtained good engineering and social benefits. In the single-layer tunnel lining, the design of shotcrete put forward higher requirements for early strength and waterproof performance. In this study,an orthogonal experimental method of four factors(cementitious materials, W/C ratio, fly ash and silica fume)and three factor levels was adopted to carry out the experiments of proportioning of HPC the strength as the standard. Through field test its performance than ordinary shotcrete is greatly improved: the early strength of 4h from 0 to 1.6 MPa, 12 h strength increased by 72%,1 d strength increased by 73%, 28 d strength increased by 21%;28 d permeability level from P8 to P16. Meet the requirements of single layer lining for high performance concrete.In this study, the plastic zone is similar as the area of broken rock zone. The excavated face and step that influence the area of broken rock zone were studied by numerical simulation(FLAC3D) and the paper research on the area of broken rock zone of double way of passenger dedicated railway tunnel with a speed of 350 km/h with different surrounding rock grade(II~V) and different depth(50 m,100 m,200 m,300 m) and support theory of broken zone was applied to rock classification of railway tunnel, presenting rock classification table, support parameter table. The support parameter of surrounding rock grade IV and 50 m depth is designed. Taking consideration of age-based property of shotcrete, compare the performance of high performance shotcrete(HPS) and ordinary shotcrete lining and the results show that there is no significant difference in displacement and plastic zone control, but the stresses of HPS is about 26% larger, indicating that it can develop better performance of concrete.