湿态钢纤维泡沫混凝土初期支护减震特性研究

Research on the Damping Characteristics of Wet Steel Fiber Foamed Concrete Initial Support

研究目的:水是隧道结构常见地质环境,分析研究新型初期支护材料的减震性能必须考虑水的影响。因此本文在试验探究适宜作隧道初期支护的钢纤维泡沫混凝土的基础上,进一步试验分析水对其力学性能的影响;最后通过数值模拟构建三维复合式衬砌隧道结构模型,探究在不含水地层与富水地层中新型初期支护的减震性能。研究结论:(1)湿态钢纤维泡沫混凝土的动态模量随含水量的增加而增大,准静态单轴抗压强度与抗拉强度随含水量的增加而降低;(2)钢纤维泡沫混凝土初期支护有明显的减震效果,减震率最高达41.43%,围岩级别越高,减震效果越显著;在地震设防烈度升高时,减震效果提升不明显;(3)在不含水地层中,不同厚度初期支护的减震效果有边际效应,而在富水地层中没有这种边际效应,分别给出了不同工况条件下的钢纤维泡沫混凝土初期支护厚度的推荐值,可供实际施工参考。

Research purposes:Water is a common geological environment of tunnel structure.It is necessary to consider the influence of water on the damping performance of new primary supporting materials.In this paper,the influence of water on the mechanical properties of steel fiber foamed concrete which is suitable for tunnel initial support is analyzed.Finally,a three-dimensional composite lining tunnel structure model is built through numerical simulation to explore the damping performance of the new initial support in water-free and water-rich strata.Research conclusions:(1)The dynamic modulus of wet steel fiber foamed concrete increases with the increase of water content.The quasi-static uniaxial compressive strength and tensile strength decrease with the increase of water content.(2)The initial support of steel fiber foamed concrete has obvious shock absorption effect,the shock absorption rate is up to 41.43%;The higher the level of surrounding rock,the more significant the damping effect;When the intensity of seismic fortification increases,the improvement of the damping effect is not obvious.(3)In water-free strata,the effect of initial support with different thickness has a marginal effect,while in water-rich strata,the marginal effect disappears.The recommended values of initial support thickness of steel fiber foamed concrete under different working conditions are given for reference in practical construction.