Study On Consolidation Creep Model Of Bioenzyme Treated Organic Soil

Organic matter is widely present in soil.Organic matter is adsorbed on the surface of soil particles and forms rheological material wrapped on the surface of soil particles through the interaction of surface charge and water,which is the main material basis of creep of organic soils.Organic soils have significant creep property,large compressibility and low bearing capacity,which can be improved and reused in engineering by chemical treatment.It is less costly and more flexible than the use of large amounts of land by nearby stockpiles and long-distance transport of replacement soils.Curing agents such as cement and lime can be used to improve organic soils,but the organic matter in the soil tends to react with cement and lime to inhibit the development of strength of the improved soil and a large amount of curing agent is needed to achieve the curing effect.The production of cement and lime requires the consumption of large amounts of mineral resources and energy,and accompanied by large amounts of carbon emissions,which increases the cost of the project and is not conducive to environmentally friendly development.Biological enzymes are non-toxic,non-polluting and environmentally friendly biological reagents produced by plant fermentation,which can effectively reduce soil moisture and improve soil density and bearing capacity.Biological enzymes can combine with organic matter in the soil to form a stable structure to improve the strength of the soil and achieve curing effect,which is highly efficient and environmentally friendly compared to traditional curing agents.Soil creep is prone to engineering problems such as instability and excessive settlement,affecting the life and safety of the project.In this thesis,in order to study the creep characteristics of bioenzyme treated organic soil,we used bioenzyme to improve the artificially configured organic soil,carried out one-dimensional consolidation creep tests on the improved organic soil with different load ratios and different bioenzyme contents,analyzed the changes of bioenzyme treated organic soil,analyzed the influence of the bioenzyme contents on the creep model parameters of the improved organic soil,established the Merchant creep model and the hyperbolic creep model based on the bioenzyme contents,and carried out validation and comparison analysis on the two creep models.The research and main results of this thesis are as follows.1.The basic physical and mechanical property indexes of the test soil samples were determined through basic geotechnical tests.The artificially configured organic soil was amended with bioenzyme and the one-dimensional consolidation creep tests were carried out on modified organic soils with 0%,2%,4%,6%,8%bioenzyme contents and 6%organic matter content under different loading conditions.2.The strain versus time,pore ratio versus logarithm of time and stress versus strain curves of the bioenzyme treated organic soil were obtained based on the results of the one-dimensional consolidation creep test.The relationship between strain and time of the bioenzyme treated organic soil shows a hyperbolic variation pattern,and the creep deformation increases with the increase of stress level.The pore ratio of the modified organic soil is linearly related to the logarithm of time,and the pore ratio gradually decreases with the increase of time.The relationship between stress and strain of the modified organic soil is non-linear,and the larger the stress level is,the more obvious the non-linearity is.3.Based on the results of the one-dimensional consolidation creep test,the strain versus time curve of the bioenzyme treated organic soil was fitted by the Merchant creep model,the creep model parameters were obtained,the influence of the stress level on the creep model parameters was analysed,the influence of the bioenzyme content on the creep model parameters was analysed,and a creep model of the bioenzyme treated organic soil based on the Merchant theory was established.4.Based on the results of the one-dimensional consolidation creep test,a hyperbolic function was used to describe the strain versus time relationship of the bioenzyme treated organic soil,the hyperbolic creep equation which is used to describe the relationship between stress,strain and time was established,the creep model parameters were calculated,the influence of the bioenzyme content on the creep model parameters was analysed,and a creep model of the bioenzyme treated organic soil based on the hyperbolic theory was established.5.The Pearson correlation coefficient was used to validate and compare the Merchant creep model and the hyperbolic creep model of bioenzyme treated organic soil.Both creep models are capable of describing the strain versus time relationship of bioenzyme treated organic soil.The hyperbolic creep model is more accurate in describing the strain versus time relationship of bioenzyme treated organic soil at lower stress levels,the Merchant creep model is more accurate in describing the strain versus time relationship of bioenzyme treated organic soil at higher stress levels.