不同洞形与加载方式对深部岩体分区破裂影响的模型试验研究

随着地下工程开挖深度的增加，深部洞室围岩将产生不同于浅部洞室的分区破裂现象。为研究分区破裂的破坏机制和形成机制，以淮南矿区丁集煤矿高地应力深部巷道为工程背景，采用模型相似材料和数控真三维加载模型试验系统，开展圆洞、城门洞和马蹄形洞在沿洞轴向和垂直洞轴向加载条件下的洞室开挖真三维地质力学模型试验。模型试验研究表明：(1) 初始最大主应力平行于洞轴方向且其量值超过1.5倍围岩单轴抗压强度是深部岩体产生分区破裂的重要条件；(2) 洞室分区破裂的范围与洞形和洞室尺寸有关，洞室尺寸越大，分区破裂范围越大。模型试验结果有效揭示分区破裂的形成条件和破坏规律，为深入研究高地应力深部岩体的非线性变形特征与破坏机制奠定了坚实的试验基础。

MODEL TEST STUDY OF ZONAL DISINTEGRATION IN DEEP ROCK MASS UNDER DIFFERENT CAVERN SHAPES AND LOADING CONDITIONS

The zonal disintegration phenomena which are different from shallow buried cavern will form with the increasing of the excavated depth of underground engineering. In order to investigate the failure mechanism and formation conditions of the zonal disintegration，taking the Dingji coal mine of Huainan mine area with high geostress as background，the true 3D geomechanical model tests for circular cavern，horseshoe cavern and gate cavern have been carried out by adopting model similar material and numerical controlling true 3D loading model system under different loading condiotions of the parallel loading and vertical loading along cavern axis direction. The model test results show that：(1) The zonal disintegration is going to happen when the direction of maximum principal stress is parallel to the tunnel axis and the value of stress exceeds 1.5 times uniaxial compressive strength of surrounding rock mass. (2) The boundary of zonal disintegration depends on the shape and size of cavern；the larger the size of the cavern is，the larger the zonal disintegration range is. The model test results help to reveal the generating condition and failure laws of zonal disintegration，which lays a solid test foundation for further studying nonlinear deformation characteristics and failure mechanism of deep rock mass.