急曲线隧道盾构超挖量及铰接角的理论算法

Theoretical Algorithm for Over-excavated Volume and Articulation Angle During Shield Tunneling Along Sharp Curves

为提高盾构机开挖急曲线隧道的能力,应准确预估超挖刀的伸出长度与范围、铰接角等几何作业参数。目前上述参数仅基于盾构与隧道设计轴线的平面几何关系确定,无法适应三维复合曲线隧道的施工要求。基于空间向量分析理论,提出三维复合曲线隧道超挖刀长度与范围、铰接角的理论算法,并基于Fortran语言实现算法的求解。对实际隧道工程盾构的几何作业参数进行了模拟,通过模拟值与实测数据的对比,验证了理论算法的有效性。结果表明:铰接角的实测值与模拟值整体拟合较好,当盾构机在曲线段掘进时,铰接角的实测值略大于模拟值,是由于实际施工中以刀盘的中心点拟合隧道设计轴线为纠偏目标,与理论算法中以管片拼装中心点拟合隧道轴线的理想掘进状态存在差异;模拟的超挖刀范围窄于实测范围,而超挖刀伸出长度的模拟值比实测值略大,存在的微小差异来自于理论算法假定盾构机不挤压地层且周围地层不变形,而实际施工中地层存在一定的变形量。

In order to improve the ability of shield machine during the curved excavation of shield tunnel,operation parameters such as copy cutter length,range and articulation angle should be precisely forecasted.However,above operation parameters,which were set based on plane geometry theory of shield and tunnel design axes,failed to meet requirements of the 3D curved tunnel construction.A theoretical algorithm of copy cutter length,range and articulation angle of the 3D curved tunnel was proposed based on the spatial vector analysis.Calculation formulas were solved by Fortran program.Furthermore,the simulation of operation parameters in an actual shield tunnel was performed.Values of simulation were compared with measured results to verify the validity of the proposed algorithm.The results show that measured values of articulation angle are well consonant with the ones of simulation.When shield machine excavatesat curved sections,the measured value is a little larger than the value of simulation.Through taking fitting tunnel design axes in the center point of cutter disc as an object of rectifying a deviation in the actual construction,there are differences between measured values and ideal values of fitting tunnel design axes in the center point of segment.The simulated range of copy cutter is narrower than the measured range but the simulated value of copy cutter length is a little larger than the measured value.The main reason of differences is that there exists deformation in the stratum in the actual construction but the assumption of the shield is that there is no extrusion as well as no deformation.