动力湿化作用下炭质泥岩路堤填料崩解及强度特性试验

Disintegration and strength characteristics of carbonaceous mudstone embankment filler during dynamic humidification

为研究动力湿化作用下预崩解炭质泥岩路堤填料崩解规律及强度变化特性,对不同含水率及动力作用下的预崩解炭质泥岩路堤填料进行动力加载试验和点荷载试验,研究含水率w、动荷载F和加载次数N对颗粒崩解及破碎强度的影响。研究结果表明:在动力湿化作用下,预崩解炭质泥岩路堤填料崩解形式为表面破裂;在崩解过程中,粒径d为2~5 mm的颗粒质量分数下降幅度最显著,粒径d≥2 mm的颗粒质量分数随w、F和N增加而降低,粒径d<0.5 mm的颗粒质量分数变化趋势则相反;崩解率S_(DRE)与N、F和w呈正相关,但S_(DRE)增加幅度随着N增加而逐渐降低,w越低,N和F对S_(DRE)的影响越小;w、N和F对级配分形维数D的影响与S_(DRE)对分形维数D的影响类似,根据D与w、N和F的拟合函数计算泥岩极限分形维数D_(ult)为2.58。N和F对颗粒破碎强度σ_(f)影响较小,w和特征粒径d_(e)与σ_(f)呈负相关,w越小,σ_(f)受d_(e)影响越大,而w增加引起σ_(f)减小的幅度随d_(e)增大而逐渐降低;当w≥7%,d_(e)≥20 mm时,炭质泥岩σ_(f)处于w和d_(e)的非敏感区。

In order to study the disintegration law and strength variation characteristics of pre-disintegrated carbonaceous mudstone embankment filler under dynamic and humid conditions,the disintegration test and point load test of pre-disintegrated carbonaceous mudstone embankment filler at different water contents and under dynamic load were carried out.The effects of water content w,dynamic load F and loading times N on the change of particle gradation and particle strength were explored.The results show that the disintegration form of carbonaceous mudstone embankment filler in the dynamic humidification is surface fracture.During the disintegration process,the mass fraction of the particle size d in the range of 2-5 mm decreases most significantly.The mass fraction of particles with d≥2 mm decreases with the increase of w,F and N,while the mass fraction of particles with d<0.5 mm is the opposite.The disintegration rate S_(DRE)is positively correlated with the N,F and w.However,the increase of S_(DRE)gradually decreases with the increase of N.The lower the w,the smaller the effect of F and N on S_(DRE).The effects of w,N and F on fractal dimension D are similar to that of S_(DRE).According to the fitting function of D and w,N and F,the ultimate fractal dimension D_(ult)of mudstone is 2.58.N and F have little effect on particle crushing strengthσ_(f).The characteristic particle size d_(e)and w are negatively correlated withσ_(f).The smaller the w,the greater the influence of d_(e)onσ_(f).However,the magnitude of the decrease inσ_(f)caused by the increase of w decreases gradually with the increase of d_(e).When w≥7%,d_(e)≥20 mm,σ_(f)is in the non-sensitive area of w and de.