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安然, 蔡苏童, 姚传芹, 汪亦显. 干燥过程中花岗岩风化土开裂与收缩特征的试验研究[J]. 岩土工程学报. DOI: 10.11779/CJGE20230948
引用本文: 安然, 蔡苏童, 姚传芹, 汪亦显. 干燥过程中花岗岩风化土开裂与收缩特征的试验研究[J]. 岩土工程学报. DOI: 10.11779/CJGE20230948
Experimental study on cracking and shrinkage characteristics of granitic weathered soil during drying process[J]. Chinese Journal of Geotechnical Engineering. DOI: 10.11779/CJGE20230948
Citation: Experimental study on cracking and shrinkage characteristics of granitic weathered soil during drying process[J]. Chinese Journal of Geotechnical Engineering. DOI: 10.11779/CJGE20230948

干燥过程中花岗岩风化土开裂与收缩特征的试验研究

Experimental study on cracking and shrinkage characteristics of granitic weathered soil during drying process

  • 摘要: 摘要:为了揭示干燥气候条件下花岗岩风化土的开裂与收缩特性的演化机制,开展不同脱湿时间的微米计算机层析识别(μ-CT)扫描与收缩试验,获得了花岗岩风化土三维孔隙分布与收缩曲线,并讨论了裂隙演化规律与收缩特征的关联性。结果表明:根据μ-CT扫描的三维重建模型,花岗岩风化土内部组分分为黏土、石英颗粒、铁质胶结物和孔隙;总孔隙率和连通裂隙度随脱湿时间增加显著提高;在干燥脱湿作用下,不同等效孔径Re的孔隙均有一定程度的增加,等效孔径大于100 μm的裂隙数量增幅最明显;花岗岩风化土的收缩曲线分为正常收缩、残余收缩和零收缩阶段;表面裂隙率Rsc在一定程度上可以预测土体收缩特征,但由μ-CT扫描获得的三维裂隙与土体真实收缩变形具有更好的相关性。

     

    Abstract: Abstract: To reveal the evolution mechanism of cracking and shrinkage characteristics of granite weathered soil under dry climate conditions, the 3D pore distribution and shrinkage curves of granite weathered soil were obtained by micron computer chromatography identification (μ-CT) scanning and shrinkage tests at different dehumidification times. Furthermore, the relationship between rules of crack evolution and characteristics of shrinkage was discussed. The test results show that the internal components of granite weathered soil can be divided into clay, quartz particles, iron cements and pores according to the 3D reconstruction model from μ-CT scanning. The total porosity and content of connected cracks increased significantly with the elapse of dehumidification time. Under the drying effects, the pores with different equivalent aperture (Re) increased to a certain extent, and the number of cracks with equivalent aperture larger than 100 μm increased most obviously. The shrinkage curve of granite weathered soil can be divided into normal shrinkage, residual shrinkage and zero shrinkage stages. Besides, the ratio of surface cracks (Rsc) can be used to predict the shrinkage characteristics of soils, but the index of three-dimensional cracks obtained by μ-CT scanning may have better correlation with the real shrinkage of soils.

     

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