The Infection On The Humic Acid In The Progress Of Solidifying Soft Soil By Cement Soil

Humic acid is an organic compound which distributing abroad and structure compose complex,and it is important for the structure and function of the ecosystem in the global environment.At present,there are more and more research about the interactivity between humic acid and metal,and the research about humic acid more than fulvic acid. Because of the different of the origin,and the method of the abstraction and research ,the result is very different, because of it neglect the complexity and the existent of the humic acid.Since origin and constituent of our country soft soil are various, there is different in the consolidation effect of cement soil, even failure stabilization exited in some projects. According to the study on deformation and strength, organic matter in soft soil can impede the hydration of cement, which influences the formation of cement soil strength. Generally we used firming agent reduce this affect,but the mechanism of humic acid is still in investigation.So soft soil in different maritime space(Lian Yungang ,Guangzhou,Tianjin,Ruian,Ningbo,Changchun) are studied in this paper associated with the project of"study on the influence of organic matter in the progress of marine soft soil foundation consolidation''and"The research of processing method based on blows fills in the cohesive soil solidification mechanism and the soft basement''sponsored by the national natural scientific fund. The action and effect of humic acid in the progress of formation of cement soil is studied on the basis of indoors mechanical tests, chemical tests, microstructure , spectral analysis .The grey prediction GM model, BP neural network model and damage law are used on examination result analysis,and it have well fitting accuracy. The interaction mechanism between Humus and cement soil,which through adsorption ,exchange and complexation ,can supply favorable grounds to solidifying soft soil.1. Extracting and study of humic acid to cement stabilized soil:In this passage , the basic characters , photochemistry characters ,molecular structure characters are tested. Also the existing state of humic acid in different environments is discussed.It is concluded that the character between original soil and the cement stabilized soil is different.The humic acid in cement stabilized soil can be divided to three kinds , they are loose combined state,stable combined state and close combined state. And the content of stable combined state is more than loose combined state. The ratio of fulvic acid(FA)and humic acid(HA) is a little small in stable combined state.The extraction of humic acid is influenced by cement particle which can be eliminated by ultracentrifugal and extending the time of centrifugate. The disturbance of reducibility mass,such as Cl^-,Fe²⁺,NO₂^- must be eliminated when testing organic component.2.Study on the humic acid various components action mechanism: The cement soil infrared spectrogram result indicated that, the humic acid the 2820cm place absorption peak is stronger in the soil, the main reason is in the cement alkalinity environment contains the oxygen functional group the oxidation. The steady knot condition humic acid content is higher than pine tying condition, also humic acid optical density E465/E665 changes in a big way, reflection cement soil humic acid molecular structure trend simplification. Soil humic acid pine tying condition is the addendum circle calcium union condition preparation, the steady knot condition is the inner loop preparation is and the hard aluminum union shape, as well as in close integration with condition humic acid three kind of shapes. (SEM) the picture indicated by the microscopic structure that, soil body organic content higher, construe of cement soil looser, obtains the compressive strength with the experiment to be low is consistent.The Furey acid (FA) and the humic acid (HA) the content is bigger to the soil body solidification influence, the steady knot condition Furey acid (FA), may hinder soil system the cement hydration product growth in particular, thus influence cement solidification soil intensity. When the cement mixes quite lowly into, cement caking the function nearly does not have the influence, when the cement mixes into quite is high when the aggregate completely fills to the hole, cement caking the function only then can fully display. In cement hydration process, calcium ion and aluminum accretion of ion, soil body humus then with the cement adsorption union, the calcium ion and the humic acid forms is the humic acid calcium salt, hindrance and reduction cement hydration product production. The sur- medicinal preparation may effectively weaken the humic acid not good to affect, the test result indicated when joins the sodium sulfate, the calcium chloride attains the reinforcement effect to be better.3.Study on the cement soil intensity and the pellet rank minute GM gray prediction model study: Indicated through the gray system fundamental research result that, the cement soil grain-size distribution to limits the compressive strength influence without the side remarkable, its grain-size distribution and thecement soil limits the compressive strength without the side gray connection to have has the foreword ,namely changes slightly along with the pellet particle size, its influence is stronger. When the humic acid component is WFA, the compressive strength is strongest, belongs to the most superior factor. Limits the compressive strength take the different cement content cement soil without the side as the characteristic sequence ,establishes GM (1,7) the gray prediction model, compares the difference simulation value and the experimental value, the average error basically satisfies the experimental request, reflects the cement quantity, between the cement soil stress and the pellet particle size relations well. In model regulation coefficient for just when, displays causes the cement soil for the corresponding cementr soil pellet grain-size distribution the non- side to limit the compressive strength enhancement; When this place regulation coefficient for negative value, the pellet particle size quantity increase cement soil limits the compressive strength to reduce. Looking from the curve overall tendency, when the cement quantity increases ,the humic acid component reduces to its compressive strength influence. 4.Research on the humic acid influence cement soil compression strength by BP neural network model: The cement soil compressive strength is predicted when with the BP neural network algorithm, it may obtain a more reasonable result in the model , when data-in cohesive force relative bigger ,we obtained result error big, also convergence rate slower, explained the empirical datum the accuracy to operates the result influence to be bigger. The strength of cement prediction is more than variables, the non-linearity, the major time lag problem.Selecting the test data in the cement soil, we establishes the BP neural network model by the C++ programming language. The cement compressive strength are influenced by each kind of factor , its value scope is been bigger. The artificial neural network is one kind biological modelling model which based on the physiology intelligent, it simulates the human cerebrum the thought ability, for establishment complex non-linearity mapping approaching, but provides the powerful tool. It is better through the actual computation and the analogue result contrast effect.5.The research on the damage law of humic acid to the cement soil: Through cement soil stress-strain curve analysis, identical local same test specimen cement content different, then the stress-strain relations change is different. Uses the curve fitting stress strain experiment, we makes the correlation data the fail-safe analysis, thought this experimental sample the stress-strain relations may indicate by the model, and it can predicate the stress-strain of this kind of cement soil. The cement soil test specimen to limit the compression-test research discovery, the cement soil distortion and the damage process may divide into the crack and the hole closed stage, the cement soil line elastic response stage, the micro flaw stable state expansion stage and the crack links up - the unstable condition expansion four stages, the water soil stress strain conforms to the index relations.