Acoustic Emission of Biocemented Calcareous Sand Base

Abstract

A meter-scale model test with microbially induced calcite precipitation (MICP) is an efficient method to validate this sustainable soil reinforcement technique. Mechanical and physical testing methods for evaluating the biocementation efficiency of model tests are still being explored. In this study, a meter-scale calcareous sand base was treated with MICP. The mechanical and physical characteristics of the sand base, such as strength, shear-wave velocity (SWV), and acoustic emission (AE) signals, were measured via cone penetration tests (CPTs), bender element tests, unconfined compression tests (UCTs), and AE tests. The CPTs showed that the strength of the sand base increases with the biotreatment level, and the maximum strength could be reached at eight-cycle treatment. The biotreatment showed heterogeneity within the sand base, which can be reflected by the differences in the dry density, SWV, and unconfined compression strength of the segmented specimens. The AE signals from both the CPTs and UCTs with avalanche analysis showed that the damage model in the tests involves both fracture and friction.