# Study on the Influence of Moisture Content and Void Ratio on the Disintegration of Red Clay
###### Abstract
However, when explaining the disintegration mechanism, they discussed the two indicators separately, neglecting the influence of moisture content on soil structure. [PERSON] et al. [25] considered that compaction and moisture content are the fundamental causes of soil disintegration, and established the relationship between compaction, moisture content, and disintegration rate using effective porosity; however, only using compaction to describe the quality of soil structure cannot establish the influence of soil microstructure on the disintegration of red clay. [PERSON] et al. [26] and [PERSON] et al. [27] considered that pore pressure and matric suction in the soil are the main controlling factors of unsaturated soil collapse. [PERSON] et al. [28] used CT to test the crack changes during the mudstone disintegration process and found that tiny cracks in the mudstone are important flow paths for external water to enter the rock mass, but they ignored the transformative effect of mudstone swelling on the rock mass structure. [PERSON] et al. [29] used scanning electron microscopy (SEM), nuclear magnetic resonance (NMR), and CT to observe the microstructure changes during the rock disintegration process and explore the relationship between pore structure and mudstone disintegration. With the development of nuclear magnetic resonance (NMR) detection technology, the determination of soil moisture distribution and microstructure has also become increasingly mature. For example, [PERSON] et al. [30] found that the pore distribution in the soft soil of Nansha is multi-porous, with small pore size and a bimodal distribution, with the pore size mainly concentrated between 0.1 and 20 \(\upmu\)m. [PERSON] et al. [31], through nuclear magnetic resonance experiments, found that the T\({}_{2}\) distribution curve of expansive soil and kaolin clay moves to the right with the increase of moisture content, and the variation of the minimum relaxation time is not obvious, while the maximum relaxation time increases with the increase of moisture content. [PERSON] et al. [32] used nuclear magnetic resonance technology to measure the microstructure of cohesive soil under different moisture content and compaction conditions, and found that cohesive soil with lower dry density contains more large pores, and the initial moisture content has a certain influence on the number of small pores. [PERSON] et al. [33] found that the initial moisture content and dry density have important influences on the pore size and distribution of compacted clay, and the pore diameter increases first and then decreases with the increase of the initial moisture content, while the dry density inhibited the effect of initial moisture content on pore structure. [PERSON] et al. [34] found that the micro-pores of residual granite soil slightly decrease with the number of dry-wet cycles, and the effective shear strength has a negative linear relationship with the pore volume content. [PERSON] et al. [35; 36] used nuclear magnetic resonance technology to explore the variation law of pore structure of expansive soil in salt solution. The scholars mainly focused on researching the distribution law of soil moisture (or the pore structure of saturated soil) using nuclear magnetic resonance technology. However, they did not conduct in-depth research on quantitative indicators such as the disintegration rate and pore structure characteristics obtained by applying NMR. In terms of the mechanism of disintegration, the currently mainstream idea is that when the moisture content of red clay is relatively low [37; 38; 39; 40], its disintegration mechanism is mainly due to the rapid entry of water molecules into the soil under the influence of matric suction. This leads to compression of gas in the closed pores, an increase in tensile stress in the closed cavity, rapid disintegration of the soil sample, and a large amount of gas escape.