This paper presents an experimental investigation of the soil water retention curve (SWRC) and volume change curve over a large suction range (0–286.7 MPa), and microstructure evolution of Guilin lateritic soil under drying and wetting processes. The scanning electron microscopy results show that the reconstituted and compacted samples have very different microstructures. The soil samples compacted at optimum water content features flocculation of the colloids showing a low degree of particle orientation, while the reconstituted samples prepared from slurry produce dispersed arrangement of particles showing a high degree of particle orientation. The pore size distribution curves of reconstituted and compacted samples show the unimodal and bimodal distributions, leading to S-shaped and double S-shaped SWRCs, respectively. At the same initial density, the soils with a low degree of particle orientation (like compacted samples) exhibit less shrinkage than those with a high degree of particle orientation (like reconstituted samples). The mercury intrusion porosimetry test results show that the drying and wetting processes and initial density clearly affect the macropores of the compacted samples, while the micropores remain almost unchanged. For the reconstituted samples, the drying and wetting processes and initial density primarily affect the micropores.

本文对大吸力范围（0–286.7 MPa）下的土壤保水曲线（SWRC）和体积变化曲线进行了实验研究，并研究了干燥和湿润过程中桂林红土的微观结构演变。扫描电子显微镜结果表明，重构和压实的样品具有非常不同的微观结构。以最佳含水量压实的土壤样品的特征在于胶体的絮凝，显示出较低的颗粒取向度，而由浆液制备的再生样品产生的分散排列的颗粒显示出较高的颗粒取向度。重构和压实样品的孔径分布曲线显示出单峰和双峰分布，分别导致了S形和双S形SWRC。在相同的初始密度下，具有较低颗粒定向度的土壤（如压实样品）的收缩率要小于具有较高颗粒定向度的土壤（如再生样品）的收缩率。压汞法测试结果表明，干燥和润湿过程以及初始密度明显影响压实样品的大孔，而微孔几乎保持不变。对于重构的样品，干燥和润湿过程以及初始密度主要影响微孔。压汞法测试结果表明，干燥和润湿过程以及初始密度明显影响压实样品的大孔，而微孔几乎保持不变。对于重构的样品，干燥和润湿过程以及初始密度主要影响微孔。压汞法测试结果表明，干燥和润湿过程以及初始密度明显影响压实样品的大孔，而微孔几乎保持不变。对于重构的样品，干燥和润湿过程以及初始密度主要影响微孔。