超大跨扁平地下洞库锚喷支护受力特征研究

针对巨跨超扁平洞库围岩荷载分布的复杂性和施工的困难性，为填补国内远超50 m级巨跨超扁平洞库修造技术的空白，提升对支护结构和围岩受力特征的认知，依托巨跨洞库工程展开了巨跨超扁平地下洞库开挖过程中支护技术的研究。通过对巨跨洞库锚喷支护进行数值模拟，得到不同支护结构的受力情况，并对不同支护结构的支护效果进行对比分析。结果表明： 1）在开挖过程中，系统锚杆轴力和喷射混凝土结构内力总体较小，相比之下锚索的拉力较大； 2）在拆除两侧岩柱时，锚索拉力增幅较大； 3）锚索轴力监测数据和数值模拟的变化趋势相同，验证了数值模拟计算结果的合理性。因此，可以认为在整个施工过程中，锚索对围岩稳定起主要支护作用。

Stress Characteristics of Bolt Shotcrete Support in Giant Span Flat Underground Cavern

Because of the complex load distribution of surrounding rocks, giant span flat caverns frequently face more construction challenges. The support technology of a giant span flat underground cavern is studied to investigate the construction technology of a giant span underground cavern (far more than 50 m-level) in China and improve cognition of supporting structure and surrounding rock stress characteristics. Through a numerical simulation analysis of anchor shotcrete support of giant span cavern, stress characteristics of different support structures are obtained, and the supporting effect of different support structures is compared and analyzed. The results show the following: (1) The axial force of anchor cable and the internal force of shotcrete structure are relatively small during excavation process, but the tensile force of anchor cable is relatively large. (2) When removing the rock pillars on both sides, the tension of the anchor cable increases sharply. (3) The variation trend of anchor cable axial force monitoring data matches that of numerical simulation, thereby confirming the validity of the numerical simulation results. Therefore, the anchor cable can be considered to contribute to the stability of the surrounding rock throughout the construction process.