IN-SITU TESTING STUDY ON BEARING CAPACITY OF ROCK BOLTS AND CORRESPONDING CALCULATION METHOD
宜兴抽水蓄能电站地下厂房锚杆承载力现场试验研究与计算方法

The research achievements of in-situ tensile test on the bearing capacity of rock bolts for support of large-scale excavation are presented. The different methods of in-situ tensile test for bolts are discussed. Based on the test results,the distribution characteristics of axial strain along the anchored part and the displacements on bolts head and adjacent rock mass surface are given out. The influence of the dip angle of rock bedding planes on the stress of rock bolts and the coherence between grout and bolt are analyzed. At last,a new method is proposed to determine the bearing capacity of rock bolts. This method is far different from conventional methods. This method is derived from the in-situ test data and the uneven distribution characteristics of shear stress along the bolt are considered. The length of bolt is determined by the stressed part and the anchored part. The bearing capacity of rock bolts is calculated by the peak shear stress along bolt. The calculated results by the method are in accordance with the real force condition in bolting engineering.