基于“S”型函数的隧道开挖变形预测模型

基于不同开挖阶段围岩阶段变形曲线几何特征,提出一种基于"S"型函数的隧道开挖全过程变形预测模型,实现隧道开挖全过程中的围岩变形预测。对比分析了常用"S"型函数适应性,建立了基于Logistic模型的隧道围岩变形分析模型,模型精度控制在2%以内,并提出了模型参数辨识过程。利用Logistic隧道围岩变形模型,讨论了隧道开挖瞬时变形特征,提出了一种求解隧道瞬时开挖变形值的方法,计算出不同工程条件下瞬时变形值处于2. 192～43. 288 mm,瞬时位移占最终位移的6. 61%～18. 33%。以马尾山隧道为工程实例,建立了具体的工程隧道围岩变形模型,得到隧道开挖瞬时位移值处于1. 041～9. 475 mm,瞬时位移占总位移比值处于5. 52%～36. 44%。

Deformation prediction model of tunnel excavation based on "S" type function

In order to realize the prediction of surrounding rock deformation during tunnel excavation, according to the geometric characteristics of surrounding rock deformation curves of different excavation stages, a deformation prediction model for tunnel excavation based on "S" type function is proposed. The contents include: (1) Based on the geometric characteristics of the surrounding rock deformation curve of the tunnel, The tunnel deformation prediction model of "S" type function is proposed, and the adaptability of common "S" type functions is compared and analyzed. The deformation model of tunnel surrounding rock deformation based on Logistic model is established. The model precision is controlled within the 2%, the model parameter identification process is proposed. (2) Through the deformation model of surrounding rock of Logistic tunnel, the transient deformation characteristics of tunnel excavation are discussed. A method for solving the instantaneous excavation deformation value of tunnel is proposed. The instantaneous deformation value under different engineering conditions is 2.192~43.288 mm. The displacement accounts for 6.61%~18.33% of the final displacement. (3) Taking the Ma Weishan tunnel as an engineering example, the deformation analysis model of the surrounding rock of the concrete tunnel is established. The instantaneous displacement value is 1.041 mm~9.475 mm, and the instantaneous displacement is the total displacement ratio at 5.52% ~ 36.44%.