钢筋钢纤维混凝土内衬受内水压计算模型

Calculation Model of Steel Fiber Reinforced Concrete Inner Lining Subjected to Internal Water Pressure

盾构隧洞复合衬砌承受高内水压力时,内衬型式的选择是设计难点,纤维混凝土具有较好的抗拉性能及开裂后承载能力,目前还没有被广泛应用于输水隧道内衬设计中,相关的计算方法研究较少。文章推导了假定开裂模式下的内衬受内水压力的三阶段计算模型:弹性阶段,内衬的受力可按弹性力学的公式进行计算;应力调整阶段,内衬径向变形持续增加,内水压力变化较小;继续承载阶段,内衬继续承载,此时内衬可视作开裂部分与未开裂部分串联组成的弹簧单元组进行计算。将该模型与有限元进行了比较,结果较为一致。利用该模型对输水隧洞进行了分析,结果表明,钢筋钢纤维混凝土内衬承载效果较好,可以作为输水隧洞内衬设计的一种选择。

When shield tunnel composite lining is subjected to high internal water pressure,the choice of inner lining type is the difficult topic in the design.Fiber reinforced concrete has great tensile properties and post-cracking bearing capacity,but it has not been widely used in the inner lining design of water conveyance tunnels,and related calculation methods are still lacking.Based on the assumption of cracking mode,the calculation model of inner lining subjected to internal water pressure is proposed in this paper.At the elastic phase,the stress of the lining can be calculated according to the formula of elastic mechanics;at the stress adjustment phase,the radial deformation of the lining continues to increase,while the change of the internal water pressure is small;at the stress continuous increase phase,the lining can be regarded as a spring unit group composed of a cracked part and a non-cracked part in series.This method calculations agreements well with FEM simulations.This method is applied to a calculation of a water conveyance tunnel,the results show that the steel fiber reinforced concrete lining has a good bearing effect and can be used as a choice for the design of the water conveyance tunnel inner lining.