# An Investigation into Bol Anchoring Performance during Tunnel Construction in Bedded Rock Mass
###### Abstract
The result showed that the failure modes of anchored specimens are affected by anchoring type, and they are further divided into shearing extension and shearing offset. [PERSON] et al. [32] simulated the failure mechanism of tunnel segmental lining joints and confirmed that the deformation of the circumferential joints consisted of opening and dislocation, but dislocation was dominant. In addition, to explore the impact of various factors, [PERSON] et al. [33] carried out shear testing of different bolt sizes, materials, installation angles, specimen strengths, and others. Based on their findings, [PERSON] et al. [34] established a computational formula of structural-plane-anchored specimen shearing strength, which they verified through simulation tests. Furthermore, [PERSON] et al. [35] employed a physical simulation method to assess the impact of the bolt pre-stress force on the shear-bearing capacity of rock mass. [PERSON] et al. [36] studied the mechanical properties of fractured rock mass under anchoring conditions and uniaxial compression. They further verified the bolt \"dowelling function\" in terms of the fractured rock mass. [PERSON] et al. [37; 38] used a method of anchoring the origin rock specimens and performed respective tensile, uniaxial compression, and pressure-shear tests on rocks. They detailed the rules of crack initiation, extension, and so on of the anchored specimens and verified the relationships between the anchorage and enhancement of the specimen's mechanical strengths (tensile, compressive, and shear). In addition, they analyzed the anchoring performance. Based on the classical beam theory and the variational principle of minimum complementary energy, [PERSON] et al. [39] analyzed and determined the resisting mechanical behavior of anchor bolts for different rock mass strengths and bolt diameters. [PERSON] et al. [40] conducted conventional static and dynamic drawing load tests on bonding bolts with end anchorage. The experimental results showed that the distribution of axial stress of a bonded anchor bolt is triangular under static loading. [PERSON] et al. [41] designed an artificial material and loading system to study the influence of bedding cohesion and anchoring behavior of bedded rock mass. The results showed that the axial stress-strain curve of bedded rock mass under the reinforcement of bolts presents the features of strain softening and secondary strengthening. As shown above, considerable studies and research results have helped elucidate the jointed rock mass anchoring performance. Obviously, however, many other factors affect the bolt shearing property for jointed rock mass, and the complicated rock strengthening of the jointed rock mass by bolting remains not fully understood. Moreover, the existing theory of anchorage support falls does not fulfil engineering requirements, and designers have to adopt empirical methods to address the stability of rock in most cases. The intention of this paper is to explore the performance of bolts for bedded and jointed rock masses and to figure out the mechanical properties and failure mode of the rock by different anchoring methods. This study is organized as follows. Section 1 reviews the previous studies made in the field of bolt reinforcement effects. In Sections 2 and 3, a laboratory test program is designed to analyze the mechanical properties (under uniaxial and shear force) from the viewpoint of mechanical effects and the failure modes of jointed rock with different anchoring methods. Section 4 presents verification of the bolt anchoring effect on a bedded shale tunnel by means of a site test. Finally, Section 5 concludes the current study.