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刘东海, 谷泽永, 陈辉, 王文东. 不同PCM结晶度的相变黏土碾压过程离散元模拟[J]. 岩土工程学报. DOI: 10.11779/CJGE20240816
引用本文: 刘东海, 谷泽永, 陈辉, 王文东. 不同PCM结晶度的相变黏土碾压过程离散元模拟[J]. 岩土工程学报. DOI: 10.11779/CJGE20240816
Discrete element simulation on rolling process of PCM-clay with different crystallinity[J]. Chinese Journal of Geotechnical Engineering. DOI: 10.11779/CJGE20240816
Citation: Discrete element simulation on rolling process of PCM-clay with different crystallinity[J]. Chinese Journal of Geotechnical Engineering. DOI: 10.11779/CJGE20240816

不同PCM结晶度的相变黏土碾压过程离散元模拟

Discrete element simulation on rolling process of PCM-clay with different crystallinity

  • 摘要: 掺混石蜡基相变材料(PCM)的相变黏土为解决寒区黏土心墙冬季施工防冻控温问题提供了潜在途径。但是,PCM在不同温度下特有的相态变化(即结晶度不同)会导致相变黏土呈现不同的压实特性,不同PCM结晶度的相变黏土碾压参数控制标准有待进一步研究。考虑到现场碾压试验不仅成本高,而且在环境多变下难以控制PCM达到设定结晶度的试验温度,本文采用PFC 3D软件,根据碾轮及荷载模拟相似率,建立了不同PCM结晶度下相变黏土碾压离散元模型,通过室内击实试验对离散元模型的有效性进行验证,分析了不同碾压参数对相变黏土压实质量的影响,进而给出不同PCM含量及其不同结晶度下的相变黏土碾压参数的控制标准。结果表明:激振力过小时,即使增加碾压遍数也难以达到大激振力的压实效果,适当提高激振力有利于压实;PCM的结晶度提高会使相变黏土压实干密度降低,通过增加碾压遍数、减小碾压速度和适当减小摊铺厚度等措施,可提高相变黏土的压实效果,达到PCM未结晶时的最大干密度。本研究可为不同施工温度下分析相变黏土的碾压质量提供新的方法,也可为不同PCM结晶度下合理确定心墙相变黏土压实质量控制提供理论依据。

     

    Abstract: Paraffin-based phase-change-material mixed clay (PCM-clay) provides a potential way to solve the problem of anti-freezing and temperature control during the construction of clay core wall in cold regions in winter. However, the phase change of PCM with different crystallinity at different temperatures leads to different compaction properties of PCM-clay. The control standards of compaction parameters of PCM-clay with different PCM crystallinity need to be further studied. Considering that the field rolling test is not only costly, but also difficult to control the test temperature of PCM to reach the set crystallinity under the changeable environment. Accordingly, PFC 3D software was used to establish the rolling discrete element model of PCM-clay with different PCM crystallinity according to the similarity rate of roller and load simulation. The validity of the discrete element model of PCM-clay was verified by the indoor compaction test results. The influence of different rolling parameters on the compaction quality of PCM-clay was analyzed, and then the control standard of PCM-clay rolling parameters under different PCM content and different PCM crystallinity was given. The results show that when the vibratory force is too small, it is difficult to achieve the compaction effect of large vibratory force even if the number of rolling passes is increased. Properly increasing the vibratory force is beneficial to compaction. The increase of the crystallinity of PCM will reduce the dry density of PCM-clay. However, increasing the number of rolling passes, reducing the rolling speed, reducing paving thickness and other measures can effectively improve the compaction effect of PCM-clay after PCM crystallization, and achieve the maximum dry density of uncrystallized PCM. This study can provide a new method for analyzing the compaction quality of PCM-clay at different construction temperatures, and also provide a theoretical basis for reasonably determining the compaction quality control of PCM-clay in core wall with different PCM crystallinity.

     

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