南山口隧道位于郑西高速铁路巩义市南山口镇,主要为分布于第四系上更新统冲洪积及中更新统坡洪积的厚层砂质黄土、粘质黄土、粗圆砾土,下覆上第三系砂岩,二叠系主要为粉砂质泥岩、粉砂岩,属土、岩多层结构。施工出现塌方及施工后塌方等现象主要发生在构造角砾岩及其上的粗圆砾土。 Nanshankou Tunnel is located in Nanshankou Town, Gongyi City, of the Zhengzhou-Xixi Expressway. It is mainly composed of thick sandy loess, clay loess, rough gravel soil distributed in the Paleogene alluvial and mid-Pleistocene slope-flood accumulations in Quaternary. Underlying the Tertiary sandstone, the Permian is mainly silty mudstone, siltstone, belongs to soil, rock multi-layer structure. The occurrence of landslides during construction and landslide after construction mainly occur in the construction of breccias and rough gravel on them.