中文摘要：

喷混凝土拱肋是加固软弱围岩的一种有效支护形式,其间距主要根据经验确定,可能偏大或偏小。为了揭示拱肋间距对加筋拱肋加固效应的影响,采用基于有限差分法的FLAC3D软件对施工期某地下厂房交通洞软弱围岩在拱肋间距分别在1.0―5.0m之间变化情况下变形、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：拱肋间距越大,围岩变形、顶拱最大主压应力和塑性屈服区越大,拱肋承受荷载越大;且拱肋间距介于2.0―3.0m时,能充分发挥围岩自承作用和拱肋支护潜力,围岩变形稳定满足要求,支护成本最低。本文的研究成果为确定喷混凝土拱肋合理间距提供了重要参考。

英文摘要：

The spray concrete arch ribs are the one of cost-effective support structure for reinforcing the weak- ness zone;however the distance of arch ribs is mainly determined by the engineering experience,which is probably too big or small. In order to reveal the evolution law of the mechanical response for surrounding rock reinforced with different distances of ribs, comparison analyses of its deformation, stress and plastic yield zone of the weakness zones tunnel section for a underground plant in construction are simulated with the finite dif- ference software FLAC3D when the spray concrete arch ribs change with distances from 1.0m to 5.0m.The simulation results show that：the greater distance of arch ribs ,the more greater deformation, maximum principal stress and plastic zone area of surrounding rock, the greater bearing,load for arch ribs;and the distance of the arch ribs between 2.0m and 3.0m,the bearing capacities of surrounding rock and the supporting characteristics are both the best, the deformation and stability of the tunnel meet the requirements and the cost of the rein- forcements is lowest.The results lay a good foundation for the reasonable distance of the arch ribs in the un- derground engineering.