蠕变作用下将军崖岩画区岩体变形机理与加固方案研究

Deformation Mechanism and Treatment Measures of Rock Mass in Rock Painting Area of Jiangjun Cliff under the Creep Effect

针对全国重点保护文物连云港将军崖岩画区岩体因锦屏磷矿开采出现严重开裂的问题,在现场调查的基础上,利用3DEC软件对岩画区因蠕变作用造成的岩体变形情况进行了数值模拟.结果表明,变形体的破坏模式为弯曲—倾倒—拉裂破坏,在岩体蠕变作用下,采空区顶板不断倾倒下沉,40年间位移量达25 cm,岩画区岩体呈现加速拉裂趋势,最大开裂宽度达到1.5 cm,延伸深度约20 m,模拟得到的结果与实际调查的结果基本一致.采用无黏结型预应力对穿锚索和端头锚索相结合的方法加固后,通过3DEC软件模拟加固20年后岩体的变形.结果表明,岩画区各监测点位移曲线斜率趋于一致,岩画区东西边界位移差曲线近于水平,监测点总位移差由未加固时的8 cm下降到4.5 cm,水平位移差则由未加固时的6 cm下降到3 cm,证明该方案加固效果良好.

In this paper,rock painting area of Jiangjun Cliff in Lianyungang is a national key protection relic,which suffers severe cracking caused by the excavation of Jinping phosphate.On the basis of field investigation,the numerical simulation software of 3DEC is used to analyze the process of toppling deformation under the creep.The results show that the failure mode of toppling deformation body is bend-toppling-pull crack.Under the creep effect of the rock mass,the goaf roof continues to fall and sink.The displacement accumulates to 25 cm during 40 years. The cracking speed of the rock mass around the cliff painting is accelerated.The maximum width of the cracks is 1.5 cm and the crack depth is about 20 m.The numerical calculating value of displacement is relatively identical with the investigation.The reinforcement measures are used the unbonded opthread-prestressed strand anchor and end-anchored cables.We use 3DEC to simulate the rock mass deformation after 20 years of the reinforcement.The results show that the displacement curve is collected from the various observation sites in the rock mass near the cliff painting tends to be consistent,while the displacement difference curve of east and west boundary is close to the level.We find the difference of the total displacement reduces from 8 cm before the reinforcement to 4.5 cm,and the horizontal displacement difference reduces from 6 cm before the reinforcement to 3 cm.All above prove that the proposed measure is effective.