The applicability of microbially induced calcite precipitation (MICP) for internal erosion control in gravel–sand mixtures

Abstract

Seepage-induced internal erosion in earth-filled embankment dams has been attracting attentions of civil engineering researchers and practitioners for decades.Microbially induce carbonate precipitation (MICP), due to its proved performance in soil enhancement and permeability control, can be potentially used for internal erosion control. This paper examines the applicability of MICP for internal erosion control in gravel-sand mixtures using a large one-dimensional column test apparatus which incorporates the implementation of MICP. Visual obersverations, erosion characteristics and hydromechanical behaviours of Non-MICP and MICP treated gravel-sand mixtures were investigated through a series of constant-pressure erosion tests. Test results confirm that MICP treatment can reduce the cumulative erosion weight, erosion rate and axial strain relative to Non-MICP soil. The magnitudes of hydraulic conductivity for all tested samples before erosion process fall into a range from 5.5×10 -5 to 8.0×10 -3 m/s. After erosion process, Non-MICP soils and MICP treated soils with low cementation concentrations experience a significant increase in the hydraulic conductivity. Furthermore, the hydro-mechanical coupling analysis was conducted and different erosion modes were identified for low and high concentrations of cementation solution, respectively. Fundamentally, the efficiency of internal erosion reduction is controlled by the calcium carbonate precipitation content within the tested soils. Higher precipitation content can facilitate the formation of larger clusters of cemented sand particles, thus reducing the likelihood of erosion.

Microbial induced solidification and stabilization of municipal solid waste incineration fly ash with high alkalinity and heavy metal toxicity

“…pasteurii at the low OD600 of about 0.14. Jiang et al [18] has also reported that OD600 value of the final suspension ready for MICP treatment is 0.454 ±0.137. From the above views, it is believed that the bacterial concentration in present work was sufficient to induce ureolytic reactions.…”

“…A series of applications are situated in the field of bio-remediation. The bio-remediation includes the removal of heavy metals from contaminated soils [16–17], the control of internal erosion in gravel-sand/sand-clay mixtures [18–19], and the treatment of groundwater contaminated by heavy metals or radio nucleotides [20–22]. It should be noted that most of the previous researches mentioned above are carried out on the porous materials in conditions of pH 5–9 with certain limited types of heavy metal.…”

Laboratory method of microbial induced solidification/stabilization for municipal solid waste incineration fly ash

“…(1) and (2). In most researches, the solution contained urease-producing bacteria, calcium chloride, urea, nutrient, etc., was added into the soil column to form calcium carbonate that binds the soil particles together, improving the engineering properties of soils [[7], [8], [9], [10]]. CO(NH2)2+2H2Otrue⟶UreaseCO32-+2NH4+Ma++CO32-→M2CO3a…”

Comparison of Nanomaterials with Other Unconventional Materials Used as Additives for Soil Improvement in the Context of Sustainable Development: A Review

“…When the content of precipitated calcium reached more than 1% weight percent, hydraulic conductivity of the treated sand is lower than 10 −4 cm/s [ 50 ]. Of course, the average precipitation amount of calcium carbonate increases with the concentration of urea and calcium chloride in the solution, but the distribution of calcium carbonate in soil is not uniform [ 54 ].…”