Bireflex Target is used to measure strain of underground areas (tunnel, communication duct, and common utility duct), slopes, and structures. 
It is applied the light reflection principle of a geodimeter for surveying. 
By installing Bireflex Target in a tunnel and recording the location of each point with a geodimeter, calculate the displacement amount of a tunnel as continuous surveying is performed, 
 
▶ Bireflex Target is used to measure strain of underground areas (tunnel, communication duct, and common utility duct), 
   slopes, and structures.
▶ Right after tunnel digging, drill the hole which can install anchor pin of 30~40mm size at installation point. 
▶ Fix the anchor pin to the drilling Hole. Then using connecting bolt at anchor pin, fix Bireflex target. 
▶ after measuring by using geodimeter, record the measured value at Data sheet and record the distance from the mining
   when measured, lining degree, excavation pattern, timbering pattern.