Influence of Soda Content on Desiccation Cracks in Clayey Soils

Self Cite

Shrinkage, deformation, and cracking will occur under extreme climate conditions such as drought, due to the accumulation of salt inside the soil during the evaporation of water on the surface of the soil. In this study, the image processing method was used to quantitatively analyze the dehydration cracking process of clay polluted by alkaline pollutant sodium carbonate on the basis of experiments. The mechanism of the effect of sodium carbonate concentration on the shrinkage cracks of clay was discussed through the analysis and comparison of different concentrations of sodium carbonate samples. The results showed that the water loss and shrinkage cracks of alkaline contaminant clay were developed in different stages. Firstly, first-level cracks developed diagonally or parallel to the edge of the container, and then second-level cracks developed along the main cracks with an angle of close to 90°. Most of the third-level or higher-level cracks were approximately perpendicular to the second-level cracks or the edge of the container and developed in parallel. In the cracking stage, the water loss ratio of the sample had a good positive correlation with the surface crack ratio. The slope of the fitted curve increased with the increase of the sodium carbonate concentration. With the increase of sodium carbonate concentration, the water loss ratio and the width of first-level cracks of clayey soil decreased, and the total length and the number of cracks increased, while the surface cracking ratio increased first and then decreased.

Section: Methodsmentioning

confidence: 99%

Effect of Alkali Pollutant in Influencing Crack Propagation in Soils

Yuan

Cui

Chang

et al. 2021

Self Cite

“…e embankment filled with high liquid limit or expansive soil tends to have a high natural moisture content due to the large plasticity of the soil. Water loss, volume shrinkage, and deformation of the saline soil appeared under the condition of high temperature exposure [4]. e surface water loss rate was much faster than the inner water loss rate in the compacted embankment.…”

Section: Introductionmentioning

confidence: 95%

Evaporative Cracking Characteristics of the Embankment Soil Affected by the Saline Concentration

Liu

Xia

et al. 2022

Embankment soil affected by saline can not only cause roadbed settlement, frosting, and road cracks but also cause corrosion and cracking of roadbed pipelines, which seriously affects the stability of the road. Water evaporation and dry cracking of the saline soil mainly cause soil swelling, poor water stability, and corrosive characteristics of the embankment soil. In this study, the evaporative cracking characteristics of soil with different saline concentrations were investigated. The results showed that the moisture content decreased linearly with the drying time in the early evaporation process, subsequently decreased slow down in the mid-term evaporation, and finally become got and remain a residual moisture content, which are 46.39%, 44.05%, 42.70%, and 40.27% with the increase of the saline concentration. The evaporation process with different saline concentrations in the soil can be divided into three stages: uniform evaporation stage, slow down evaporation stage, and equilibrium evaporation stage, which was consistent with the moisture content change. With the development of the drying time, the cracks gradually appeared on the soil surface, gradually deepened in the soil, and expanded the crack network. The development of cracks can be divided into three stages: the cracking preparation stage, the crack development stage, and the crack stable stage. The cracking began at high evaporation rate under high saline concentration, and the fractal dimension remained stable under similar saline concentration. The fractal dimension was gradually increased with the decrease of the moisture content and the increase of the saline concentration, respectively. The soil began to crack with larger moisture under high saline concentration. The drying cracks in the nature were consistent with the configuration of the cracks formed in the experimental results.

“…With the advancement of urban construction, suburban engineering construction is in full swing, and more and more high fill slopes appear [2]. e slope of multistage filling is complex [3], and many factors such as unit weight, cohesion, and internal friction angle affect its stability [4][5][6][7]. For a specific multistage filling slope, the study of the sensitivity of its stability to various factors will help to identify the most dangerous factors, so as to avoid risks in practical engineering.…”

Section: Introductionmentioning

confidence: 99%

Sensitivity of Multistage Fill Slope Based on Finite Element Model

Yuan

et al. 2021

Based on the strength reduction method, the laws of slope displacement and the changing positions of the sliding surface during the filling process are studied. The model of multistage fill slope is established by the finite element software PLAXIS. The difference is compared between the slope with no reinforcement and with reinforcement under the same working condition. Sensitivity analysis is carried out from two aspects which are internal factors and external factors. The finite element analysis shows that the settlement of the multistage fill slope with no reinforcement is mainly concentrated on the right side of the slope and gradually decreases with the increase of the filling height. The position of the sliding outlet is located at the joint of the first and the second grade of the slope. The effect of the reinforcement on the sliding surface is ideal. It is obvious that the reinforcement can supply the slope with a better position of the sliding surface, which is beneficial to the stability of the slope. The sensitivity analysis shows that unit weight, ratio of slope, and height of each grade are negatively correlated with the safety factor. At the same time, the platform width, cohesion, and internal friction angle are positively correlated with the safety factor. The internal friction angle has the greatest influence on the stability of the slope. Besides, the platform width and the height of each grade should be controlled at about 4 m. The sensitivity analysis provides a reference for the design of the multistage filling slope.