As an increasing number of metro lines have been planned or executed in urban area, new tunnel undercrossing existing tunnels has been commonly practiced. Construction of the existing tunnel causes disturbance to the surrounding soil and hence affects the operational parameters of undercrossing tunneling especially the chamber pressure of EPB machine. However, very limited research studies this effect. To fill the gap of knowledge, this paper proposed a new method for calculating the chamber pressure of EPB tunneling machine in undercrossing project. First, the effect of existing tunnel on surrounding soil is classified as removal-and-replacement effect, excavation-induced-disturbance effect, and elastic foundation beam effect. Second, based on analysis of the mutual interaction between existing tunnel and the undercrossing tunneling, three zones have been identified to study the chamber pressure of EPB machine. Next, a new method is proposed to calculate the chamber pressure in the process of undercrossing existing tunnel. Finally, the proposed method has been verified with measured data from two engineering cases. The comparison results show that the proposed method is in good agreement with the measured data, indicating that it is reasonable with high accuracy.

随着在城市地区规划或执行越来越多的地铁线路，通常会在现有隧道下穿行新的隧道。现有隧道的施工会对周围的土壤造成干扰，从而影响地下穿越隧道的运行参数，特别是EPB机器的腔室压力。但是，非常有限的研究对这种效果进行了研究。为了填补这一知识空白，本文提出了一种新的计算过桥工程中EPB隧道掘进机腔室压力的方法。首先，将现有隧道对周围土壤的影响分为去除和置换效应，开挖引起的扰动效应和弹性地基梁效应。其次，基于对现有隧道与地下隧道之间相互作用的分析，确定了三个区域来研究EPB机器的腔室压力。接下来，提出了一种新方法来计算穿越现有隧道的过程中的腔室压力。最后，通过两个工程案例的实测数据验证了该方法的有效性。对比结果表明，该方法与实测数据吻合良好，表明该方法合理，准确。