浅埋偏压隧道进洞施工稳定性分析及控制

Stability Analysis and Control of Shallow Buried Biased Tunnel Construction

浅埋偏压隧道进洞施工常面临边仰坡失稳的问题,危及隧道施工人员和设备的安全。文中从分析某浅埋偏压隧道进洞施工的不稳定性特征入手,在分析裂缝成因和后期影响的基础上,提出处置措施。采用有限元差分软件FLAC3D建立三维数值模型,基于Hoek-Brown强度准则和强度折减法,对隧道进洞施工过程进行模拟,并通过位移、安全系数、塑性区范围等指标评估地层和衬砌结构的稳定性。对锚杆加固、注浆加固,以及两者结合加固3种方式的加固效果进行模拟和分析,确定最优加固方案。通过对比采用加固措施前后隧道衬砌典型位置监控量测数据,对加固效果进行验证。结果表明,采用加固措施后,隧道变形的大小和速率均大幅降低,保证了隧道施工的安全。

The instability of the side elevation slope is often occurred in the tunnel entry construction of shallow buried biased pressure tunnel,which endangers the safety of tunnel construction personnel and equipment.Starting with the analysis of the instability characteristics of the construction of a shallow buried biased tunnel,the treatment measures were put forward based on the analysis of the cause and influence of the cracks.Then,finite element differential software FLAC 3D was used to establish a three-dimensional numerical model.Based on Hoek-Brown strength criterion and strength reduction method,the construction process of tunnel entry was simulated,and the stability of stratum and lining structure was evaluated by displacement,safety factor,plastic zone range and other indicators.Then,the reinforcement effects of bolt reinforcement,grouting reinforcement,and the combination of the two were simulated and analyzed to determine the optimal reinforcement scheme.Finally,the effect of the reinforcement measures was verified by comparing the monitoring data of typical positions of tunnel lining before and after the reinforcement measures were adopted.The results show that the size and speed of tunnel deformation are greatly reduced after adopting the reinforcement measures,and the safety of tunnel construction is guaranteed.