Influence of Lateral Pressure on the Mechanical Performance of Bolted Specimens under Biaxial Compression

The influence of lateral pressure (sigma(2)) on the stability of the surrounding rock of roadway increases after excavation. The rock bolt is usually used to improve the stability of the surrounding rock. Therefore, it is important to understand the biaxial compressive behaviors of the bolted samples influenced by lateral pressure. In this study, biaxial compression experiments are carried out to investigate the biaxial compressive properties of bolted rock samples influenced by lateral pressure. The results show that bolting can improve the peak strength, inhibit the post-peak strength attenuation and reduce the pre-peak brittleness of the bolted rock mass. With the increase of lateral pressure, the strength and elastic modulus of the bolted samples increases approximately parabolic and linearly, respectively. The failure modes of the bolted samples influenced by lateral pressure can be divided into splitting failure and compression-shear failure. A reinforcement mechanism of bolt is observed, namely axial action, axial and transverse action at the pre- and post-peak stages of the bolted samples. Based on a modified true triaxial Mohr-Coulomb strength criterion and this bolt reinforcement mechanism, a new method for calculating the equivalent cohesion and equivalent internal friction angle of the bolted specimens under biaxial compression is proposed. The research results of this paper have certain reference value for the stability control of roadway