预崩解炭质泥岩路堤填料工程性能试验研究

预崩解炭质泥岩作为路堤填料已在我国西南地区路堤工程中广泛应用,通过室内试验系统分析压实度、含水率以及酸碱环境对预崩解炭质泥岩路用性能、力学性能及渗透特性的影响,并结合娄底龙琅高速对其应用情况进行研究。研究结果表明:预崩解炭质泥岩的回弹模量、CBR值、抗压强度随压实度的增大呈线性增长,随含水率的增大呈现先增大后减小的波动趋势;CBR值和抗压强度随pH值的增大呈负相关变化,而回弹模量则随pH值的增大呈正相关变化;预崩解炭质泥岩渗透系数随压实度的增大逐渐减小,随含水率的增加逐渐增加,pH值的增大均可使渗透系数增大,其中压实度对预崩解炭质泥岩的渗透系数影响最大;随含水率的增加,预崩解炭质泥岩微观结构由粒状转变为片状,酸性环境下试样片状结构的厚度较碱性环境薄,碱性环境下试样微观结构呈块状且粉末状成分增多。

Experiment study on road mechanical properties and permeability characteristics of pre-disintegration carbonaceous mudstone

Pre-disintegrated carbonaceous mudstone has been widely used as embankment filling in southwest China. The effects of compaction degree, water content and acid-base environment on road performance and permeability characteristics of pre-disintegrated carbonaceous mudstone were studied. Combined with Longlang expressway project in Hunan province, its road preface were analyzed. The results show that the resilience modulus, CBR value and compressive strength of pre-disintegrated carbonaceous mudstone increase with the increase of compaction degree, and increase first and then decrease with the increase of water content. The acid-base environment will reduce the CBR value and compressive strength, while the resilience modulus will gradually increase with the increase of pH value. The permeability coefficient of pre-disintegrated carbonaceous mudstone decreases with the increase of compaction degree, and increases with the increase of water content. The pH value can increase the permeability coefficient, and the compaction degree has greatest influence on permeability coefficient of pre-disintegrated carbonaceous mudstone. With the increase of water content, the microstructure of pre-disintegrated carbonaceous mudstone changed from granular to flaky. The thickness of the microstructure is thinner in acidic environment, and the microstructure is blocky and powdery component is gradually increased in alkaline environment.