Experimental study on Microbially Induced Calcite Precipitation for expansive soil stabilization

Zheng Lu , Yu Qiu , Jie Liu , Chengcheng Yu , Hailin Yao

Abstract

Microbially induced carbonate precipitation (MICP) is extensively discussed as a promising topic for ground stabilization. The practical effect of stabilizing the expansive soil is presented in this paper with a logical process from the bacterial activity to the treatment technology. Temperature, pH, shaking frequency, and inoculation amount are discussed to evaluate the bacterial activity. The physic-mechanic properties are also evaluated to discuss the effect of the MICP process on expansive soil. Results indicate that the MICP method achieves the mitigation of expansion. The treated soil has a low proportion of fine particles (< 5 um), the plasticity index significantly decreases, and strength values improve much. MICP process has a significant cementation effect on the soil matrix. Moreover, the infiltration model test presents the coating effect on the topsoil. According to the relation between the CaCO3 content and the treatment effect, the topsoil has better treatment than the deeper soil.

Key Words

cementation effect; coating effect expansion; expansive soil; Microbially induced carbonate precipitation (MICP); the treated soil

Address

Zheng Lu — State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan 430071, China; 2Hubei Key Laboratory of Geo-Environmental Engineering, Wuhan 430071, China
Yu Qiu — State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan 430071, China; University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
Jie Liu — Transportation Planning Survey and Design Institute Co., Ltd., Urumqi 830006, China
Chengcheng Yu — CCCC Second Harbor Engineering Co., Ltd., Wuhan, Hubei 430040, China
Hailin Yao — State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan 430071, China

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