中文摘要：

喷混凝土拱肋是软弱围岩加固中一种经济有效的支护手段,但其厚度还主要根据经验确定。为了揭示不同厚度拱肋作用下围岩力学响应规律,基于有限差分法对施工期某地下厂房软弱围岩在厚度分别为0.4-0.8m喷混凝土拱肋支护下的变形、应力和屈服区等分布规律进行了对比仿真模拟。仿真结果表明：拱肋愈厚,围岩变形和塑性屈服区愈小;且拱肋厚度介于0.6-0.7m时,围岩塑性屈服区体积减小最明显,拱顶围岩部位主压应力值最大,此时能充分发挥围岩自承作用。本文的研究成果为合理确定喷混凝土拱肋厚度奠定了良好基础。

英文摘要：

The spray concrete arch ribs are the one of cost-effective support structure for reinforcing the weak- ness zone ;however their thickness is mainly determined by the engineering experience.In order to reveal the evolution law of the mechanical response for surrounding rock reinforced with different ribs, comparison analy- ses of its deformation,stress and plastic yield zone of a underground plant in construction are simulated with the finite difference software FLAC3D when the spray concrete arch ribs change with thickness from 0.4m to 0.8re.The simulation results show that：the greater thickness of arch ribs,the better the limit deformation of surrounding rock, the smaller plastic zone of surrounding rock and supporting structure ;and the thickness of the arch ribs between 0.6m and 0.7m,the principal compressive stress value of surrounding rock is the largest, the bearing capacities of surrounding rock is the best.The results lay a good foundation for the reasonable thickness of the arch ribs in the underground engineering.