考虑地层三维空间分布的盾构掘进模拟

Numerical Simulation of Shield Tunneling Incorporating 3D Spatial Distribution of Strata

为研究复杂地层条件下盾构掘进引起的地层扰动规律,提出了一种考虑地层三维空间分布的盾构掘进模拟方法.该方法利用Kriging算法构建三维地质模型,通过条件判断算法将地层空间分布信息嵌入到有限元模型中,进而实现考虑地层三维空间分布的盾构掘进模拟.此外,采用C#语言编写了复杂地层盾构掘进模拟前处理程序.以长沙地铁四号线为例,根据掘进断面内极软岩、软岩、坚硬岩的占比,选取具有3种不同地层条件的区段,利用该前处理程序构建了土压平衡盾构机掘进过程模型,并开展模拟.模拟结果显示盾构掘进断面内极软岩占比增大会导致地表最终沉降量显著增加.相比于极软岩占比为50%的掘进断面,全断面极软岩处的地表最终沉降量增加了11.67 mm.模拟结果与实测数据规律一致,验证了所提方法的有效性.

In order to study the stratum disturbance law caused by shield tunneling under complicated stratum conditions,a simulation method of shield tunneling considering the three-dimensional spatial distribution of the stratum is proposed.This method uses the Kriging algorithm to construct a 3D geological model.The 3D geological information is then integrated into a finite element model via a conditional judgment algorithm,so as to facilitate the numerical simulation of shield tunneling with 3D geological information.According to the proposed method,a preprocessing program for the simulation of shield tunneling in complex strata is developed by C#language.A case study of the Changsha Metro Line 4 project is illustrated here.Three sections with different stratum conditions were chosen.And the excavation process of the earth pressure balance shield(EPBS)machine was simulated by preprocessing program with different proportions of extremely soft rock,soft rock,and hard rock in the shield tunneling face.Simulation results reveal that the increase in the proportion of extremely soft rock in the shield tunneling face can lead to a significant increase in the final surface settlement.Compared with the tunnel section with a 50%proportion of extremely soft rock,the final ground settlement at the full-sectional extremely soft rock was increased by 11.67 mm.This finding is consistent with the measured data,verifying the effectiveness of the proposed method.