Enzyme-induced carbonate precipitation (EICP) has emerged promising in various geotechnical applications, and been presented as an alternative to the traditional cementitious materials-based ground improvement method. However, study on mechanical properties disintegration behavior of EICP-reinforced sea sand subjected drying-wetting cycles are limited. This investigated against impact (D-W) cycles. The uniaxial compressive strength (UCS) tests were performed discuss effect EICP-treated sand....

A suitable bearing capacity of foundation is critical for the safety civil structures. Sometimes reinforcement necessary and an effective environmentally friendly method would be preferred choice. In this study, potential application enzyme-induced carbonate precipitation (EICP) was investigated reinforcing a 0.6 m bedding layer on top clay to improve underneath underground cable duct. Laboratory experiments were conducted determine optimal operational parameters extraction crude urease...

The aim of this study is to disclose the feasibility improving thermal conductivity and mechanical strength quartz sand mixed with steel slag treated by enzyme-induced carbonate precipitation (EICP). In work, effect content (SSC) number treatment cycle (N) on EICP-treated specimens were investigated. immersion method was adopted for specimen preparation. measured transient plane source (TPS) unconfined compressive (UCS) obtained through a uniaxial compression test. Moreover, SEM test...

Biocemented shale soils are composite materials, and their micromechanical properties difficult to measure using common macromechanical tests. In this work, nanoindentation tests were conducted study the effects of microstructures, crystal types calcium carbonate, locations test points on biocemented soils. The transformation process carbonate during biogrouting was revealed scanning electron microscopy X-ray diffraction imaging techniques. results showed that a significant amount voids...

In situ recycling is one of the most effective methods to dispose earth pressure balance (EPB) shield waste muck with residual foaming agents high moisture content. this context, response surface methodology (RSM) was employed quantify effects independent variables, including flocculant dosage, defoamer and drying mass (MDM) their interactions on defoaming-flocculation-dewatering indices. The polymeric aluminum chloride (PACL) hydroxy silicone oil-glycerol polypropylene ether (H-G) were...

Triaxial compression creep tests were performed on salt rock samples using cyclic confining pressure with a static axial pressure. The test results show that, up to certain time, changes in the have little influence properties of rock, and curve is smooth. After this point, clearly fluctuates pressure, approximately straight line both when decreases it increases within one cycle period. slope these lines differs: greater than increases. In accordance rheology model theory, equations deduced...

Earth pressure balance (EPB) shield tunneling in coastal silty clay strata often faces the problems of clogging on screw conveyor or belt due to lumps soils formed because large cohesion particles. Soil conditioning using common foaming agents is not enough alleviate problem. Therefore, novel dispersed agent was studied this work performance and orthogonal compound tests. The foam microstructure observed an electron microscope analyze evolution mechanism bubbles for different additives. Both...

Retaining wall construction often encounters narrow cohesive backfill and the traditional theories are no longer suitable. Hence, analytical solutions for active earth pressure of on a rigid retaining rotating about bottom proposed in this paper. The principle stress rotation caused by interface friction is also included. Through typical FEM analysis derivation, multi-segmented failure surface composed logarithmic spiral curve lower part tangent line upper quantitatively determined....

Multi-scale assessment of shear behavior in the tunnel carbonaceous slate is critical for evaluating stability surrounding rock. In this study, direct tests were conducted on slates from Muzhailing Tunnel, considering five bedding dip angles (β) and four normal stresses (σn). The micro-mechanism was also examined by combining acoustic emission (AE) energy rate with PFC2D Version 5.0 (particle flow code 2D software) numerical simulations. results showed a linear relationship between peak...

The assessment of bio-cementation effect using nondestructive testing methods is important for the application microbial-induced carbonate precipitation (MICP) technique. In this study, a special grouting system was designed to conduct bio-grouting shale soils on model. ultrasound technique used evaluate effectiveness bio-cementation. A method derived estimate distribution ultrasonic wave velocity values within model based average measured surfaces. From changes isosurfaces values, evolution...

In engineering, retaining walls commonly rotate about the base (RB) and narrow backfill is often compressed. Current methods cannot accurately predict passive earth pressure of a narrow, cohesionless against wall. Therefore, this study will investigate failure mechanism under RB mode using lower-bound finite element limit analysis (FELA). The area above slip surface reached plastic state. This type phenomenon means that stress deflection occurs in backfill, which affected by boundary...