Monitoring the stress change of bolt and knowing the anchoring condition in a reasonable and effective way, accurately, can effectively prevent tunnel accident from breaking out. The stress of rock mass around the roadway is usually transferred to the anchor rod in the form of axial load, so it is of great significance to study the axial load of the bolt. In this paper, a full size anchoring and drawing experiment system was designed and established, innovatively, which realized the pull-out test of 2.5 m prestressed end Anchorage and the full-length Anchorage by using the new resin anchorage agent under vertical and horizontal loads. Through the application of fiber Bragg grating (FBG) sensing technology to the test of full-scale anchor rod, the axial force distribution characteristics of the end Anchorage and the full-length Anchorage anchor rod were obtained under the action of pre-tightening torque and confining rock pressure. The comparison indicates that the proportion of high stress range accounts for only 17.5% and the main bearing range is near the thread end of anchor rod, the proportion of main bearing range of end Anchorage is 83.3%, and the feasibility of FBG force-measuring anchor rod is verified in the field. The research results have certain reference value.
2060-T8 Al-Li alloy was friction stir butt welded under natural and water cooling conditions. Microstructures and mechanical properties of the welding joints were mainly compared and discussed. By spraying water on the top surface of stir zone, the grain size was reduced, attributing to the improvement of microhardness. The maximum tensile strength under the water cooling reached 461.1 MPa. The joint fractured at the stir zone due to the thickness reduction and the joint softening. The fracture surface consisted of many dimples with various sizes, indicating the typical ductile fracture. The strategy to apply the low heat input at the welding stage and high cooling rate at the cooling stage during FSW is necessary to obtain a high-quality FSW joint.