Study on the Solidification Effect of Dredger Fill by Microbial-Induced Calcium Precipitation (MICP)

Abstract

This paper puts forward a new soft soil reinforcement technology—microbial-induced calcite precipitation (MICP) technology—which considers the problem of dredger fill soft-soil reinforcement in Dalian Taiping Bay. In this paper, the calcium carbonate content (CCC) and unconfined compressive strength (UCS) of microbial solidified dredger fill (MSDF) samples were determined using laboratory experiments. The microstructure and chemical composition of MSDF samples were studied by SEM–EDS and XRD. The failure and reinforcement mechanism of MSDF under different experimental conditions (ambient temperature, cementation solution concentration, and clay content) were investigated. The results showed that there was a certain residual strength after the peak strength of MSDF. With the increase of ambient temperature, the number of microorganisms increased, but the activities of urease, CCC, and UCS decreased. The UCS and CCC increased with the increase of cementation solution concentration, while they first increased and then decreased with the increase of clay content. The clay content enhanced the compactness of MSDF samples but reduced the soil permeability and weakened the mineralization. There were significant differences in the morphology of microbial-induced precipitation caused by different concentrations of cementation solution.

Solidification Treatment of Wastewater and Waste Soil Generated during Binhai Reclamation: A Study on Mechanical Properties and Resource Utilization

“…Initially, εv experienced shear contraction followed by shear dilation, leading to larger εv values and weaker shear dilation behavior compared to the conventional triaxial tests. (5) The enhanced modified Cambridge model, featuring its adjusted curve, closely mirrors the curves derived from true triaxial tests. It adeptly characterizes the stressdeformation response of the soil subjected to three-dimensional stress circumstances, offering a robust theoretical foundation for the practical implementation of lightweight stabilized soil in engineering projects.…”

“…Lei et al [4] employed anionic polyacrylamide to treat solidified soil. Li et al [5] conducted an innovative investigation on soft soil stabilization in hydraulic fill using microbial-induced calcium carbonate precipitation. Soganci et al [6] utilized slag as a solidifying agent for soft clay and investigated the solidification effect when combined with marble dust.…”

Strength and Mechanism of Granite Residual Soil Strengthened by Microbial-Induced Calcite Precipitation Technology

“…They found that the solidification effect of the soil was influenced by various factors, including colony distribution, initial concentration of the bacterial solution, and standing time [18][19][20][21]. Moreover, they expanded the application of MICP technology to silty sand [22], expansive soil [23], dredger fill [24], and other types of soil solidification. Further research indicates that soil properties are closely linked to the crystal type and calcium carbonate content, which directly impacts the soil's reinforcement effect.…”