【摘要】 以第9、10窟的列柱为代表,在现场地质病害调查、室内测试和分析计算的基础上,对其地质病害进行了研究,制定了支撑方案,并采用围岩与支撑结构耦合有限元模拟方法对支撑结构的可行性和加固效果进行了计算分析。结果表明,列柱底部的应力σ1和最大剪应力τmax集中明显,τmax的最大值出现在列柱底部,从受力条件看列柱是整个围岩中受力条件最差的部位,安全隐患最大;列柱的抗压稳定性系数都不能满足规范要求,处于不安全状态;采用框架式钢管混凝土支撑框柱的支撑方案,其应力分担效果明显,列柱上所承担的竖向荷载与现状相比平均降低了63%,与现状+Ⅷ度地震相比平均降低了70%;其抗压稳定性系数可以提高到3.76～4.02,能够有效地起到保护列柱的作用,使列柱处于稳定状态。更多还原

【Abstract】 Based on the field investigation,laboratory tests,calculating and an alysis of the 9th and 10th grottos of Yungang Grottoes,this paper studies the f ormation cause of the vestibule columniation′s geological diseases and the rein forcing measures.A three-dimensional numerical method was used to simulate the wall rocks stability in different cases including the case after the support str ucture installed.The feasibility and reinforcing effect of the support structur e was analyzed based on the simulation results.Thus,it is concluded that the c oncentration of 1 and max is very obvious at the bottom of the columniation.The max of max in all calculating model is also at the bottom of the columniation. It can be found from the stress condition of the columniations that the columnia tions are in the biggest security risk,and the compression coefficient of stabi lity can not meet the requirements of code,the columniations are under unsafely state.The frame support structure composed of steel tube and concrete are desi gned.This supporting system has obvious function of the stress sharing,the ver tical load on the columniations reduce 63% in average at present case and 70% at Ⅷ intensity earthquake case.With the supporting system,the compression coeff icient of stability can increase to 3.76-4.02,so the supporting system can effe ctively protect the columniations and put them in steady state.更多还原