深埋隧道围岩爆破振动损伤效应及超欠挖控制研究

Study on blasting vibration damage effect and overbreak and underbreak control of deep buried tunnel surrounding rock

  • 摘要: 为探究深埋隧道爆破振动损伤效应与超欠挖控制规律,以宜涪高铁五峰隧道2号横洞为工程背景,采用ANSYS/LS-DYNA和HJC本构建立三维数值模型,系统模拟围岩爆破振动响应、损伤演化及超欠挖特征,结合三维激光扫描开展现场围岩爆破成型质量量化评估,针对性地提出施工优化方案并进行现场验证。研究结果表明:爆破近区围岩质点峰值振速呈“垂向>水平径向>轴向”的分布特征,垂直方向为振动能量传递的主导方向;围岩爆破损伤演化可划分为掏槽成腔、逐级扩挖、周边孔隙孔贯通3个阶段;受炮孔间能量叠加与应力集中影响,爆破近区两侧边墙和墙脚的振速高、损伤大、超挖显著,右侧墙脚最大超挖达34.7 cm,为超欠挖关键控制部位。现场实测数据显示,最大超挖均值为53.3 cm,最大欠挖均值为6.9 cm,平均线性超挖22.5 cm,均超出规范限值,与数值模拟结果差异较大。现场调查发现,周边孔实际布设间距不均、开孔数量不足,导致断面爆破能量分配失衡。据此提出以钻孔控制为核心、智能装备定位为保障、动态反馈为闭环的修正方案。现场应用结果表明,试验段欠挖消除,最大超挖均值与平均线性超挖分别降低31.7%和31.6%,超欠挖显著改善。针对优化后局部超挖问题,通过三维地质重构模型分析揭示其主要由局部楔形体掉块所致,进而提出考虑地质因素的炮孔动态优化措施。

     

    Abstract: In order to explore the blasting vibration damage effect of deep buried tunnel and the control law of overbreak and underbreak, taking the No.2 cross tunnel of Wufeng tunnel of Yifu high speed railway as the engineering background, a three-dimensional numerical model was established by using ANSYS/LS-DYNA and HJC constitutive model to systematically simulate the blasting vibration response, damage evolution and overbreak and underbreak characteristics of surrounding rock. Combined with three-dimensional laser scanning, the quantitative evaluation of blasting forming quality of surrounding rock was carried out, and the construction optimization scheme was proposed and verified on site. The results show that the peak vibration velocity of surrounding rock particles near the blasting zone presents the distribution characteristics of "vertical>horizontal radial>axial", and the vertical direction is the dominant direction of vibration energy transfer; The blasting damage evolution of surrounding rock can be divided into three stages: cutting into cavity, step-by-step excavation, and peripheral hole penetration; Affected by the energy superposition and stress concentration between blastholes, the side walls and footings on both sides near the blasting area have high vibration velocity, large damage and significant overbreak. The maximum overbreak of the right footings is 34.7 cm, which is the key control part of overbreak and underbreak. The field measured data show that the maximum average overbreak is 53.3 cm, the maximum average underbreak is 6.9 cm, and the average linear overbreak is 22.5 cm, both exceeding the specification limit, which are quite different from the numerical simulation results. The field investigation found that the actual layout spacing of peripheral holes was uneven, and the number of holes was insufficient, which led to the imbalance of blasting energy distribution in the section. Based on this, a correction scheme with drilling control as the core, intelligent equipment positioning as the guarantee and dynamic feedback as the closed loop is proposed. The field application shows that the under excavation in the test section is eliminated, the maximum average over excavation and the average linear over excavation are reduced by 31.7% and 31.6%, respectively, and the over excavation and under excavation are significantly improved. Aiming at the problem of local overbreak after optimization, through the analysis of three-dimensional geological reconstruction model, it is revealed that it is mainly caused by local wedge falling, and then the dynamic optimization measures of blast hole considering geological factors are put forward.

     

/

返回文章
返回