盾构掘进趋向预警值的分析和计算

盾构机利用激光导向进行掘进，前后点偏移值固然重要，但掘进趋向更为重要。当趋向值在合理的范围内时，可确保盾构隧道符合设计线形；超出预警范围，将会导致盾构严重偏离中线，造成无法挽回的损失。根据德国海瑞克盾构机在成都砂卵石地层中纠偏能力较差的现状，介绍趋向的概念、曲线段趋向的计算、盾构机实际纠偏能力的统计、趋向允许偏差公式的推导、趋向偏差预警值的确定，最后得到盾构趋向预警值。应用该研究成果在施工中加以严格控制，没有发生过隧道中线偏差超限的情况。

Analysis and Calculation of Trend Alarm Value in Shield Boring

System of Laser Steering(SLS) is widely employed in shield boring.The boring trend is very important in shield tunneling,which determines the oncoming boring alignment.When the trend value is in the reasonable range,the boring alignment can be guaranteed;otherwise the shield will deviate from the alignment seriously.The deviation rectification ability of Herrenknecht shield used in Chengdu Metro is poor.In the paper,the concept of shield boring trend,the calculation of the boring trend in curved sections,th...