大塌方 meaning in English

landfall
landslide
landslip

Through introducing the collapse conditions of xitangwan tunnel and the measures for treating tunnel collapse without large hydraulic pressure equipments , the article states the importance of determining the rock class in lime rock areas , and gives us practical experiences for tunnel construction through complicated geological areas
摘要通过细塘湾隧道大塌方的情况介绍及没有大型液压设备的情况下的处理措施，指出对灰岩地区围岩级别确定的重要性，为通过复杂地质地段的隧道施工提供实践经验。