近来我们为编制双线铁路隧道偏压衬砌标准设计做了一些电算工作,因为没有经验,走了不少弯路。工作之初主要的障碍是如何拟定较合理的断面尺寸。以往无论单线或双线铁路偏压隧道衬砌,均采用外墙厚内墙薄的不对称断面。因此,最初我们就按照这种传统概念拟定断面尺寸进行计算,部分计算结果见表1。该表中第1组与第2组比较,由于拱顶厚度D_(10)减少0.3米,第10截面的安全系数K_(10)仅提高0.1,而对第11截面的安全系数K_(11)几乎没有影响。表中其他几组计算结果K_(10),K_(11)也分别在2.4和2.0上下浮动,而与规范要求的3.6相差很远,虽经多次调整断面尺寸进行计算,均无明显提高,真有鞭长莫及之感。为此,我们想求助于优选法。但是优选法对于解决多因 Recently, we have done some computer work for the standard design of bi-rail railway tunnel lining, because without experience, we have taken a lot of detours. The main obstacle at the beginning of work is how to draw a more reasonable section size. In the past, no matter single or double line railway tunnel lining bias, are used thick wall thickness of the asymmetric section. Therefore, initially, we calculated the section size according to the traditional concept, and some of the results are shown in Table 1. Compared with the second group, the safety factor K_ (10) of the tenth cross section is increased by 0.1 only due to the decrease of the dome thickness D_ (10) Almost no effect. The results of K_ (10) and K_ (11) of the other groups in the table also fluctuate at 2.4 and 2.0, respectively, and are far away from the requirements of 3.6 of the code. Although the calculated results of the sections are not significantly improved after many adjustments, Really beyond expectation. For this reason, we want to resort to the law of preference. However, the preferred method to solve multiple causes