复合式衬砌是近年来兴起的一种隧道新结构型式,关于它的承载力问题,看法不尽相同。有的文献认为复合式衬砌的承载力较之同厚度的单层衬砌能提高2～3倍。有的文献认为不能提高反而降低了。也有的文献认为有防水层时承载力降低,没有防水层时承载力提高。为什么会得出如此不一致的结论呢?我们认为这是由于各人进行试验或计算所依据的假设条件不同所致。例如考虑不考虑结构与围岩的共同作用,考虑不考虑围岩的蠕变特性和各层衬砌 Composite lining is a new type of tunnel structure that has arisen in recent years. There are different opinions on its bearing capacity. Some literatures think that the bearing capacity of composite lining can be increased by 2 ~ 3 times than that of single-layer lining with the same thickness. Some literature that can not improve but decreased. Some literatures also consider that the bearing capacity decreases when there is a waterproof layer, and the bearing capacity increases without a waterproof layer. Why do we come to such an inconsistent conclusion? We think this is due to the assumptions on which each person conducts the test or calculation. For example, consider not considering the interaction between the structure and the surrounding rock, consider not considering the creep characteristics of the surrounding rock and the lining of each layer