Relationships between ecological site quality and site index of lodgepole pine and white spruce in Northern British Columbia 不列颠·哥伦比亚省北部小杆松及白云杉立地指数与生态立地质量的关系
The present paper passes on experiences in practice of advance pipe lodgepole steel tunnel support 20m at a time in a serious collapse sector. 介绍在隧道严重塌方段,采用管棚实现一次20m超前支护的实践经验。
Practice of advance pipe lodgepole steel tunnel support 用管棚实现超前支护的实践