巷道围岩卸荷破坏裂隙发展模型试验研究

为了深入研究巷道围岩卸荷破坏裂隙发展规律,针对试验考察巷道突然开挖卸荷后周边围岩裂纹的扩展状况,自行设计巷道卸荷试验装置和试验方法,采用有机玻璃板模拟围岩,中心挖去缺口部分代表巷道,遵循试验模拟的相似模型准则来设计试验,并采用高速摄影方法对模型裂缝的发展进行拍摄.试验结果表明:围岩中的弱面不但是加载过程中最容易破坏的位置,也是卸荷破坏过程中强度最薄弱的位置;裂纹的扩展方向与主要卸荷方向垂直,属于拉伸破坏类型;卸荷后在巷道的角部产生了拉应力集中.

Model test of roadway surrounding rock unloading damage fracture development

In order to research the unloading rule of surrounding rock damage fracture development,the unloading testing equipment and testing method were designed,aim to the expansion situation of surrounding crack of sudden roadway excavation after unloaded,the organic glass surrounding rock simulation was used,the center to represent the roadway with gap segments was digged,the experimental simulation model of similar rules to design tests was kept.and high speed photography method was adopted to shoot the development of the crack model.The experimental results show that: The weak section of surrounding rock not only is the position of the most damage in loading process,but also is the weakest position of strength in unloading destruction process;The crack growth direction is vertical to main unloading direction,which type belonged to stretch damage;The roadway corner produced concentrated tensile stress after unloaded.