Experiment On Improving Mechanical Character Of Dianchi Peat Soil In Kunming

Dianchi drainage basin is located in Kunming, there are many rivers and lakes in the region,what's more, there are climate warm and organic deposition rich, the peat soil distribute widely after complex biological,geochemical and physical chemistry agent. The mechanical character of dianchi peat soil is very poorer, mainly in:low bulk density, high moisture content, big void ratio, compressibility strong, consolidation slow, etc. Kunming is in surrounded with mountain on three sides, and close to dianchi in the south, with the development of economy, the city building of kunming is also increasing, there are many buildings which are built on such foundations, but the poor mechanical character of peat soil have became the important factor which restrict the stability of high buildings and construction costs. To improve the mechanical character of dianchi peat soil is an important tool of solving the prime restriction factor, it is very important and valuable.Cement,lime is simple gel materials and easy to get. The method of adding these into peat soil provides important basis for reinforcing foundation stability and minimizing foundation treatment cost when it work for improving mechanical character of peat soil. Dianchi peat soil is cured by cement,lime and gypsum, the components and curing system of soil are studied. Through single factor experiment and orthogonal experiment, analyses have been made of the influences of adding cement, lime, and mixture of cement,lime,gypsum with different volume ratio on mechanical character of peat soil, so the effect of improvement was explored and applicability of curing agent was characterized. The purpose of experiment is to get the best proportioning under experimental conditions, so as to reinforcing foundation stability and minimizing foundation treatment cost. By large amounts of test data, the following conclusion was drawn:(1) By the testing and some related material, it will be found that dianchi peat soil have high moisture content, big void ratio, compressibility strong, consolidation slow and high organic content, what's more, the soil is acid. Usually it is unsuitable for direct ground bearing stratum. If building construction has to build on this soil, it must be improved.(2)Through the result of single factor experiment, it can be known that cement and lime all are work for physical mechanics character of peat soil, the compressibility of peat soil has reduced, shear strength has improved. When the peat soil was cured by lime showed different change regularity compared with cement; relation of strength with quantity and age of lime is not a linear rule, the quantity of lime has optimum content.(3) Under experimental conditions, the strength of cement consolidated soil was improved, the compressibility of peat soil was cured effective by lime, but the strength of peat soil was improved limited.(4)Adding the mixture of cement,lime and gypsum into dianchi peat soil, the compressibility and shear strength of solidified soil all are better than cement consolidated soil and lime consolidated soil. Cement was major influence factor about the compressibility and compressive strength of solidified soil, the strength of solidified soil mainly comes from cement skeleton, which was formed by hydration and hardening of cement.(5)The best proportioning by orthogonal experiment was summed up as follows: cement6%,lime6%,gypsum0.05%.The result shows that the mechanical character of peat soil in Dianchi was improved after adding cement,lime and gypsum, the compressibility of peat soil from high to low, permeability coefficient from10-7cm/s to10-5cm/s,in addition, compressive strength has also improved.