【摘要】 为研究某城市地下小型采空区的岩层稳定性,采用三维相似模型方法,对城市潜在地质灾害问题进行了超载破坏试验研究。根据相似模拟理论,以中粗河砂为骨料配置了相似材料,采用砌筑法建立了相似模型。对岩层进行逐级竖向加载至破坏,同时监测了地表位移、矿柱和岩层顶板的应变变化,并采用内窥镜拍摄了顶板和矿柱的破坏演变过程。计算分析了岩层表面的位移、曲率变形、顶板的应变,及矿柱的破坏随荷载增加的变化曲线。综合几个方面来分析岩层的稳定性。试验结果表明:①岩层表面荷载小于2 MPa时,岩层表面变形很小,属于稳定状态;2 MPa后岩层变形呈随荷载迅速增大的状态,并表现出明显的不均匀变形特征。②岩层表面荷载不超过1.2 MPa时,顶板应变处于线性小变形阶段,属于稳定阶段;而后顶板应变随岩层表面荷载迅速增加,当荷载增大到5 MPa时,应变曲线上出现明显的拐点,顶板开始出现破坏现象。③根据影像记录,顶板先于矿柱出现受拉裂缝破坏,而后矿柱出现剪切破坏现象。因此,未来的破坏模式必将是顶板先于矿柱出现拉裂缝破坏现象,所以要从防止顶板拉裂的角度来控制岩层的稳定性。综上所述,最终确定岩层表面瞬时荷载为1.2 MPa,并且在未来的开发设计中,应充分考虑该区域岩层因存在地下不规则采空区而导致的不均匀变形问题。更多还原

【Abstract】 In order to test the stability of rock formations in underground mined-out areas under a city,a three-dimensional geomechanical modeling was carried out to test the potential destruction of the potential geo-logical hazards in a city.According to the similar simulation theory,a similar material was configured with medi-um-rough river sand as aggregate,and a similar model was established using the masonry method.The rock strata was gradually loaded until the model damage,and the surface displacements,changes in the strain of the pillars and the roof of the rock were monitored,and the destruction and evolution of the roof and pillars were photographed by endoscopes.The relationship between the displacement of the rock surface,the curvature deformation,the strain in the roof and pillars,and the increasingly load were calculated.The stability of the rock formation was comprehensive analyzed in several aspects.According to the test results,when the rock surface load is less than 2 MPa,the rock surface deformation is very small,and the deformation rapidly increases after 2 MPa,and it shows obvious non-uniform deformation characteristics.When the rock surface load does not exceed 1.2 MPa,the roof strain is in a small linear deformation stage.When the local surface load increases to 5 MPa,a sharp inflection point appears on the strain curve,and the roof plate begins to fail.According to the image records,the roof plate was damaged by tensile cracks before the pillars,and pillars appeared cracking.Therefore,the future failure mode will definitely be that the roof is damaged before the cracks occur in pillars.Therefore,the stability of the rock formation could be controlled by preventing the roof from cracking.In summary,the transient load on the surface of the rock formation is finally determined to be 1.2 MPa.In future development and design,the problem of uneven deformation caused by the existence of underground irregular goaf in rock formations in this area should be fully considered.更多还原