节理剪切过程中锚杆的变形分析

当锚杆与砂浆的粘结未破坏时，以指数曲线来描述锚杆的侧剪应力分布；而对于锚杆与砂浆的粘结遭到破坏的区段，采用抛物线来拟合。给出了粘结破坏和未破坏两种情况下锚杆的轴应力-轴位移关系，提出利用锚杆拉拔实验数据来反演确定计算中所用到的参数。并在缺少实验数据的情况下，给出了一些参数的估计方法。根据岩石是否遭到挤压破坏，分别给出了锚杆的横向剪应力与横向位移的关系式，分析了剪切过程中锚杆加固节理的剪应力-剪位移关系，讨论了对锚固节理剪切变形刚度有重要影响的一些参数。分析表明．高的岩石单轴抗乐强度、较大的锚固面积比有助于提高锚固节理的剪切刚度。分析还表明，倾斜锚杆加固的节理比垂直锚杆的剪切刚度更大，倾斜锚杆以较小的剪切位移调动了更大的剪切阻力；倾斜锚杆加固的节理抗剪强度比垂直锚杆大，提高锚固面积比能显著提高节理抗剪强度。

Analysis on the Bolt Deformation As Result of Joint Shear Displacement

When the bond between bolt and grout is intact the shear stress distribution of the bolt side is described by exponent curve. When the bond is destroyed the shear stress distribution on the bolt side can be expressed by parabolic curve. The relationships between axial stress and axial displacement with or without bond failure are presented. Some parameters can be back-analyzed from experimental data of axial tensile stress of bolt. Some parameters can be estimated by empirical equations. The relationships between transverse displacement and shear stress of bolt are also given for the cases with or without compressive failure of rock. Based on the derived analytical equations the relationships between shear stress and shear displacement of bolted joint are also presented and some parameters with significant influence on stiffness of bolted joint are analyzed. All the relevant analysis shows that higher axial compressive strength of rock and greater ratio of bolt section to bolted joint area can lead to higher shear resistance of bolted joint. The analysis also shows that joint anchored by inclined bolt has greater shear stiffness than that anchored by bolt perpendicular to joint. The joint anchored by inclined bolt has higher shear resistance with less shear displacement than the joint anchored by perpendicular bolt. The shear resistance of bolted joint can be obviously improved by higher ratio of bolt section to bolted joint area and inclined bolt.