玉维高速科色特长隧道地应力特征及工程地质意义

玉维高速紧邻金沙江西岸，全程共30座隧道，隧道占总里程的52.55%，隧道建设中极有可能遇到复杂地质问题及地应力的影响。以玉维高速科色特长隧道地应力特征为研究对象，完成了6个点的地应力测试工作及岩石室内物理力学测试，结合构造稳定性、岩爆分级、隧道空间布置分析理论完成了该隧道工程地质意义研究。研究结果表明：地应力在垂直方向上随深度以似线性增长趋势，整体表现为“浅部以走滑型地应力场为主、深部以正断型地应力场为主”的规律；地应力特征表现为“浅部区域以水平构造应力为主，深部以垂直应力为主”；各测点的最大剪应力与平均应力之比值均未达到稳定临界值，隧道周边的构造相对稳定；岩爆级别随深度逐渐增大，但级别为中等至轻微；隧道方位分析表明，隧道（右幅）K24+995至K25+730段隧道方位不利，K25+730至K28+200段隧道方位有利。

Study on in-situ stress characteristics and engineering geological significance of Kese super-long tunnel in Yuwei highway

Yuwei highway is close to the west bank of Jinsha River, and there are 30 tunnels in this highway, accounting for 52.55% of the total mileage. It is highly likely to encounter complex geological problems and the influence of in-situ stress during tunnel construction. The in-situ stress test work of 6 points and rock laboratory physical and mechanical tests were completed, the in-situ stress characteristics of Kese tunnel of Yuwei highway was taken as the research object. Combined with structural stability, rock burst classification and tunnel direction analysis theory, the engineering geological significance of the tunnel is studied. The results show that the in-situ stress increases linearly with depth in the vertical direction, strike-slip fault type stress field is dominant in shallow part and normal fault type stress field is dominant in deep part. It can be concluded that the shallow area is dominated by horizontal tectonic stress, while the deep area is dominated by vertical stress. The ratio of the maximum shear stress to the average stress of each test point did not reach the critical value of stability, and the structure around the tunnel is relatively stable. The rock burst level increases with depth, but the level of rock burst is medium and slight. The analysis of tunnel direction shows that the direction of K24+995 to K25+730 is unfavorable, while the direction of K25+730 to K28+200 is favorable.