据今年2月在石家庄召开的“铁路地道桥经验交流会”的要求,本刊将陆续选登有关地道桥的设计、施工和科研方面的资料供大家参考。望持有这方面资料的同志或单位能函寄我们,以便选登。本期选登的此文,目的在于介绍“预制钢筋混凝土后背块”,该后背块经过几处施工实践的检验证明,对于简化后背工程,降低工程造价,是一种较好的方法,值得大家参考。 According to the “Railroad Bridge Experience Exchange Conference” held in Shijiazhuang in February this year, we will select information on the design, construction and scientific research of the underground bridge one after another for your reference. Comrades or units wishing to have this information can send us a letter in order to select them. This issue of the selected article, the purpose is to introduce the “precast reinforced concrete back block”, after the back block after several construction practices proved that for the simplified back engineering and reduce project cost is a better method , It is worth everyone’s reference.