Experimental Study On The Lime Dry Jet Mixing Pile Composite Foundation

The lime dry jet mixing pile composite foundation has already been used for a long time at home and abroad, but not widely, and there are still some problems need further research and discussion.As a kind of old construction material, the production of the lime has a history of more than 4000 years in our country and its producing areas are nationwide. The lime is also a kind of cheap construction material. At present the annual production of lime in our country is about 40,000, 000 tons. Because the lime is cheap and easy to get and the lime dry jet mixing pile has good physical and chemical stabilization function and induration mechanism under water. So the purpose of this article is to continue studying and solving the problems exist in the popularization and application, and play the its role.This article makes a detailed experimental research approach after studying. 36 groups of test specimens were produced in different lime content, water content and ages indoors at first (Three specimens each group, the size was 7.07cm × 7.07cm × 7.07cm, they were made from designed proportion of water, soil and lime powder and vibrated 20 minutes at test mould after mixing evenly.), then carried on the compressive strength test. 128 lime dry jet mixingpiles were produced at random in 22 × 8m~2 place and separated into four areas according todifferent lime content, pile-length and pile spacing; and then made static load tests on the piles, the soil, the single pile composite foundation and ground of each area. In order to make the experiments to be more representative, we also tested on three-pile composite foundation and natural ground with the same static load to carry on the contrast.The result shows : The lime powder has obvious results in strengthening the weak ground of 25%~35% water content, especially for the weak ground of thin crust to the top layer that the water content more than 30%, But should not be used under the groundwater level. The characteristic value of bearing capacity of the composite foundation may get 0.2~0.25MPa when the lime content ranging from 10% to 15%, improving by 40%~50% than the natural...