Soil-Water Characteristics and Creep Deformation of Unsaturated Expansive Subgrade Soil: Experimental Test and Simulation

Abstract

The creep deformation of expansive soil has been considered as a vital threat to the safety in engineering construction because it may cause serious slope diseases in geological engineering. Meanwhile, since expansive soil usually remains in unsaturated state, its mechanical property is significantly affected by the seasonal environment. Therefore, the nonlinear deformation of expansive soil has received increasing attention, especially the humidity-dependent creep properties. This study focused on the stability of the unsaturated expansive soil subgrade considering rainfall and the creep behavior. Pressure plate extractor and direct shear tests were performed to investigate the hydro-mechanical and creep characteristics of the unsaturated expansive soil. Both the Van-Genuchten and Burgers models were applied to analyze the test results and inserted into the numerical model of the slope under rainfall infiltration. Results show that the compaction degree and the stress state was closely related to the water holding capacity of the expansive soil. The nonlinearity of the creep behavior became increasingly obvious with the increase of time and the stress level. The safety factor of the slope decreased as the rainfall time increased, and the most dangerous slide of the slope moved toward the foot of the slope. Considering the long-term creep process, there was a period of rapid growth in horizontal displacement that is detrimental to the stability of the slope. Besides, the rainfall infiltration could accelerate the slope failure before and after this creep process.

Stability of MSW Landfill Slopes Reinforced with Geogrids

“…MCM has been used by many researchers i analysis of MSW landfill slopes because it gives acceptable results and the param required for modeling can be obtained more easily than other advanced material m [7,[46][47][48]. The creep deformation and humidity distribution of MSW plays a key r the stability of MSW landfill slopes [49,50]. Given this, the Mohr-Coulomb model c accurately represent the macroscopic response without considering the mechanical Finite element analyses were performed using the soft soil creep model (SSCM) PLAXIS program for investigating the mechanical creep effect on the stability behav the MSW landfill slope.…”

Typical site seismic response analysis with reinforcement under earthquake and rainfall in the mountainous areas of China

“…Liu et al (2020) pointed out that the soil creep behavior was related to deformation, stress, strength, and time. The slope stability decreased with the rainfall time increasing, and the area with greatest sliding risk was slope foot (Yao et al, 2021). Also, the unit soil mass weight increased, and the effect stress decreased during rainfall (Terzaghi 1950;White and Singham, 2012).…”

An investigation into the physical factors that control slow mass movements

“…These advances have unmasked soil creep as the culprit behind much spectacular infrastructural damage: for instance, creep was recently revealed to cause 38-44% of burst water mains in the UK, leading to total economic costs "more than double" those related to faster mass movements in that country (Pritchard et al 2014). Thirdly, increasing recognition of the number of catastrophic failures resulting from a sudden increase in downslope motion-a "slow-to-fast transition"-has motivated a need to enhance monitoring of creep rates in space and time in order to inform early-warning thresholds (e.g., Yao et al 2021;Zhang et al 2022).…”