Studying the effect of drying on soil hydro-mechanical properties using micro-penetration method

Abstract

Understanding the hydro-mechanical response of soil during drying is significant for predicting and preventing the possible disasters related to drought climate. In this investigation, a novel micro-penetrometer was developed to characterize and quantify the drought-induced soil hydro-mechanical response based on the penetration curves, which present the variation of soil strength along depth. The relationships between the penetration resistance and soil water content, and the penetration resistance and soil suction were initially calibrated. It is found that the penetration resistance increases exponentially with decreasing water content as the soil is subjected to drying, while increases linearly with increasing suction. Before the air-entry value is reached, the drying-induced increment of soil strength is insignificant even a large amount of water is evaporated. During this stage, soil strength and water content along depth are generally uniform, and the increment of soil strength is consistent at any depth. After the air-entry value is reached, soil strength increases rapidly even water content decreases slightly. The distribution of soil strength along depth becomes non-uniform. It generally decreases exponentially with increasing depth due to the drying-induced water content and suction gradient. The predicted water content profile based on the penetration results was compared with the measured one, and good agreement was observed. It indicates that the proposed micro-penetration test can be used to characterize the hydro-mechanical response of soil during drying.

Laboratory and Field Experiments on the Effect of Vinyl Acetate Polymer-Reinforced Soil

“…Meanwhile, the soil particles also lose water. Therefore, the strength of the improved soil tends to increase [31]. However, due to long exposure, the shrinkage of soil particles exceeds the optimal range of the reticular membrane structure.…”

Study on Cracking Law of Earthen Soil under Dry Shrinkage Condition

“…Under the protection of museum buildings, although the direct threat of wind erosion and rain on the earthen sites is avoided, the ground elevation of the earthen sites in the site museum is usually lower than the surrounding surface, and under the capillary action, the site proper is directly subjected to the reciprocal action of groundwater, leading to various diseases such as surface cracking, chalking and crusting ( Figure 1 ) [ 1 , 2 ]. The cracking pattern and deterioration mechanism of the site body caused by the disaster-causing effect of shrinkage cracking has become an urgent engineering problem to be solved in preventive conservation work [ 3 ].…”

A Review of Cracking Behavior and Mechanism in Clayey Soils Related to Desiccation

“…It is commonly recognized that cracks form in clayey soils during desiccation when the tensile stress caused by suction is larger than the tensile strength of soil. Cracks can greatly weaken the engineering properties of clayey soils in various applications, such as geotechnical, water conservancy, and environmental engineering [1][2][3][4][5][6][7]. In many conditions, there is direct inducement of damage for many soil-based structures.…”

“…Desiccation cracks in clayey soils have been observed in situ by many researchers [5,9,10,[15][16][17][18], where the characteristics of cracks, such as depth, area, width, and crack ratio, under the drying environments were analyzed. Laboratory experimentations have mainly concentrated on the behaviors of clayey soil when specimens are dried from a saturated state [6,7,[19][20][21][22][23][24][25][26][27]. Indeed, there are many factors that influence crack formation and propagation such as drying conditions (temperature, relative humidity, etc.…”