Study On Solidification Mechanism And Mechanical Properties Of Biomimetic Mineralized Cemented Sand

Organisms can regulate inorganic minerals with remarkable biological traits and mechanical properties as a function of organic matrix.The principle of biological mineralization and crystallization offers a new thought for the modified reinforcement of foundation soil in civil engineering,thereby developing Microbial induced calcite precipitation technology（MICP）.The microbial mineralization-based green,environmentally friendly and efficient novel technology has attracted widespread attention of scholars.However,in view of MICP’s high economic costs,susceptibility to the environment,difficulty in controlling its distribution in situ activity,great damage of by-products accumulation to the environment and other disadvantages,how to improve the MICP technology on the basis of current research,minimize the cost,and cut down by-products while inheriting its excellent cementation properties,have become difficulties to be solved during the large-scale application of MICP technology in practical engineering.With the constant research on the mechanism of biomineralization,the biomimetic mineralization method with organic molecules as interferon inducer for controlling the growth of inorganic crystals has yield brilliant results in the research and preparation of new materials.At the same time,due to its advantages of fast reaction speed,stable performance,and nonparticipation of crystal modulators in the reaction,no generation of by-products,and low cost,it will substantially facilitate the research and application of new reinforcement technologies if being applied to the foundation soil reinforcement of civil engineering as the substitute of MICP technology of similar mechanism.After in-depth research on the principle and application of biomimetic mineralization,this paper mainly acquired following research results:（1）The method of L-Asp combined with Ca²⁺pre-organization was proposed for the first time,and Ca²⁺-H₂O-CO₃^2-reaction system metathesis method was used to simulate the biomineralization method to cement the loose sand body structure,thereby cementing and solidifying loose sand body into a complete and strong integrity in a short time.This successfully proved that L-Asp crystalline regulator-based biomimetic mineralization method is feasible to be applied to the field of civil engineering.At the same time,the impact of factors such as the number of grouting,L-Asp addition volume and the p H value of the compound solution on the mineralization effect was systematically studied.The grouting plan with the optimal cementation effect under multi-factor comprehensive influence was proposed through a simple comparison method.（2）The microscopic morphology of the biomimetic mineralized cemented sand body was systematically analyzed from the micro level using multiple micro-testing and characterization methods and the cementation mechanism between the biomimetic mineralization-induced crystals and the sand particles was analyzed.This provides a scientific basis the crystal system’s scientific regulation of biomimetic mineralization cementation,and may contribute to knowing the mineralization mechanism of organisms in the sandy soil environment from the level of molecular functional groups.（3）This paper also conducted a systematic analysis of the mechanical response and deformation characteristics of the biomimetic mineralized cemented sand body under low-frequency cyclic loading,providing a basis for evaluating the durability and stability of the venue after biomimetic mineralization and solidification in actual applications.