岩石隧道渗流模型试验相似材料的研制及应用

为提高岩石隧道渗流场分析的合理性,通过大量以控制渗透系数为核心的配比试验,提出适用于岩石隧道渗流模型试验的围岩、注浆圈及初衬等新型相似材料及其原料配比.试验以黏土、细砂和玻璃纤维为原料配制围岩相似材料,以水泥和炭渣配制注浆圈相似材料,由多层编织土工布模拟初衬相似材料.结果表明:随细砂含量加大,围岩相似材料渗透系数呈非线性增长,稳定性逐渐降低,改变玻璃纤维的含量对其渗透系数影响不明显;注浆圈相似材料渗透系数值随炭渣含量增加近于线性增长,2.5 m水头下的试验值较1.35 m水头时更大;随着编织土工布叠加层数增加,初衬相似材料平均渗透系数呈快速减小并逐渐收敛的趋势,且单次渗透系数测试结果也趋于稳定;相同隧道排水量时,二衬外拱底处水压力远大于拱顶,逐步减小隧道排水量后,拱顶水压力值上升幅度大于拱底,调水阀接近闭合时,拱顶和拱底位置的水压力接近初始水压力.研制的相似材料工作性能稳定,并成功应用于工程渗流试验中.

Development and application of a similar material for rock tunnel seepage model test

To improve the rationality of seepage field analysis of rock tunnel, a new type of similar materials and the raw material ratio of surrounding rock, grouting circle and initial lining, etc, applied in rock tunnel seepage model test, have been developed through lots of proportioning tests taking the permeability coefficient as the core control variable. The surrounding rock similar material is compounded with clay, fine sand and glass fiber. The similar material of grouting circle is prepared by cement and carbon dross. And the multi-layer woven earthwork cloth is used to simulate the initial lining. The results indicate that the permeability coefficient of surrounding rock similar material presents nonlinear growth and the stability is gradually reduced with the increase of fine sand content. The permeability coefficient is not obviously influenced by the changes of the glass fiber content. The permeability coefficient of grouting circle similar material presents approximate linear growth with the increase of carbon dross content. The test value of 2.5 m hydraulic head is greater than that of 1.35 m. The average permeability coefficient of the initial lining similar material decreases rapidly as well as showing a trend of gradual convergence with the number of layers increased. The single permeability coefficient test result also tends to be stable. The water pressure of arch bottom outside secondary lining is far higher than vault''s with the same tunnel discharge. And the vault''s water pressure increases more than arch bottom''s when water discharge gradually decreases. When approximately truning off the water valve, the arch bottom and vault''s water pressure closes to the initial water pressure. The stable performance of similar material provides a guarantee for the application in the tunnel seepage field testing.