**3. Durability Test of Shaft Lining Hybrid Fiber-Reinforced Concrete**

As the supporting structure of the shaft, the shaft lining will be affected by highpressure groundwater after the freezing wall is thawed [27,28]. Therefore, the impermeability of high-performance shaft lining concrete must meet certain requirements. The design life of the shaft is usually more than 50 years, and a large number of SO4 <sup>2</sup><sup>−</sup> and Cl1<sup>−</sup> are gathered in soil and groundwater in many areas, and the shaft often suffered from freeze–thaw action, so the harsh working environment and long service life put forward higher requirements for the durability of wall material [29,30]. At present, there is a significant amount of research on the durability of fiber-reinforced concrete, but little work on the durability of hybrid fiber-reinforced shaft lining concrete. Therefore, to make the prepared hybrid fiber-reinforced concrete of shaft lining better applied in engineering practice, the durability experiment on shaft lining concrete of reference group and hybrid fiber group was carried out by taking C60 high-strength concrete as the object.
