基于岩体指标和掘进参数的TBM净掘进速率预测模型

净掘进速率是TBM施工速度的主要评价指标,与围岩物理力学性质、TBM掘进参数之间存在一定相关性。文章以兰州水源地建设工程输水隧洞双护盾TBM施工为背景,基于现场实测数据,选择岩石单轴抗压强度、抗拉强度、变形模量、泊松比、岩石耐磨性CAI值等岩体指标,以及刀盘推力和刀盘转速等掘进参数,进行TBM净掘进速率与有关影响参数之间的单因素相关性分析,得到相应拟合公式;基于TBM净掘进速率与岩体指标、掘进参数之间的相关性,利用多元非线性回归方法建立了TBM净掘进速率预测模型。通过将兰州水源地建设工程输水隧洞实测TBM净掘进速率和预测结果进行对比,验证了TBM净掘进速率预测模型的合理性。研究结果表明:(1)在复杂的多种地质条件下,TBM净掘进速率与岩石单轴抗压强度、抗拉强度、变形模量、岩石耐磨性CAI值、刀盘推力以及刀盘转速呈负相关关系,与泊松比呈正相关关系;(2)干湿状态对岩石耐磨性CAI值有一定影响,饱和状态下岩石耐磨性CAI值与TBM净掘进速率之间的相关性更显著;(3)建立的多元非线性回归预测模型,预测精度较高,可为相似地质条件下TBM净掘进速率估算提供参考。

Prediction Model of TBM Net Advance Rate Based on Parameters of Rock Mass and Tunnelling

Net advance rate is a main evaluation index of TBM construction speed and it has something to do with the mechanical behavior of surrounding rocks and tunnelling parameters.Taking the double shield TBM adopted in the water diversion tunnel of Lanzhou water source construction project as the research background,a correlation analysis on single factor between TBM net advance rate and relevant influential parameters is conducted in terms of uniaxial compressive strength,tensile strength,modulus of deformation,Poisson′s ratio and CAI value of rock wear resistance as well as cutterhead thrust and rotation speed,and the corresponding fitting formula is obtained based on the field data.A prediction model of TBM net advance rate is established by multivariate nonlinear regression method in light of a correlation among TBM net advance rate,rock mass properties and tunnelling parameters.By comparing the measured TBM net advance rate and the predicted results of the water conveyance tunnel in Lanzhou water source construction project,the rationality of prediction model for TBM net advance rate is verified.The research re sults show that:(1)in complex and various geological conditions,the TBM net advance rate has a negative correla tion with uniaxial compressive strength,tensile strength,modulus of deformation,CAI value of rock wear resistance,thrust and rotating speed of cutterhead while it has a positive correlation with the Poisson's ratio;(2)the moisture state has certain effect on CAI value of rock wear resistance,and there is a closer correlation between CAI value of rock wear resistance and TBM net tunneling rate under saturation condition;(3)this multivariate nonlinear regres sion prediction model with a high precision can be used to estimate the TBM net advance rate under similar geologi cal conditions.