开挖条件下节理围岩特性及其锚固效应模型试验研究

Research on Failure Behaviour and Anchoring Effect of Jointed Rockmasses around an Underground Opening under Excavation by Model Testing

本文通过堆砌大比尺结构模型并进行地下洞室分步开挖模型试验，研究节理对洞室围岩变形和破坏的影响及锚杆对节理围岩的锚固效应．试验应用ＣＣＤ画像处理法和光学照相法进行位移观测。

Largesized model tests for opening excavation by steps in a jointed rockmass and with boltreinforcement of the opening are reported. The testing model has size of 180×140×15(cm3), and is tested under 16 different working conditions. The varying factors of these conditions include dip of two orthogonal joint sets, joint spacing, initial ground stress field, installing of boltanchoring or not. In the tests, CCD image processing technique and highaccurate photo technique is first applied.Test results indicate that the deformation of rockmass is mostly governed by the deformation of joints and that the collapsing areas of surrounding rocks are completely controlled by the disadvantage combination of free excavation surfaces and joint sets. It is also found that the deformation of surrounding rocks is mainly determined by the sizes of opening、dip and spacing of joint sets and initial ground stress field. The tests justified that using of rock bolts can greatly controll the deformation (esp. the vertical deformation) and failure of the surrounding rocks, and the prestressed bolts are more effective.