The Soil Bin Design Of Compaction Test And Its Application

Compaction is an effective and economical method to improve the bearing capacity andstability of soil and other basic materials. China has developed rapidly in the field ofcompaction machinery since1980s, but compared with foreign advanced level there is still alarge gap, especially the basic theoretical research is weak, and lack of new theory andtechnology of compaction, it is difficult to provide theoretical support for the development ofnew models and equipment.Researching on basic theory of compaction, there must be appropriate test facilities,especially indoor test facility. Outdoor field tests waste time and labors, and the testrepeatability and comparability is poor. Usually adopted methods both at home and abroad isto build the indoor testing soil bin, and the graded soil is placed in the soil bin, in order tocarry out research on the relevant compaction theory and compaction machinery properties.We chose medium sand, fine sand and clay as raw material when designing grading soil. Werespectively have gradation analysis on the samples of raw material, and test the maximumdry density of sand, as well test the maximum dry density and the optimum water content testof the clay.Soil cohesion and internal friction angle not only affect the difficulty of compaction, theybut also influence the bearing performance of compacted soil. The direct shear test results ofmedium sand, fine sand and clay is: less cohesive in the sand and fine sand, and greatercohesion in clay; in the medium sand, fine sand, clay, the internal friction angle increases inturn, which are as follows,32°,34°and35.5°.Determine compounding scheme of the gradation soil. In the premise of zero watercontent in three given raw materials, we confirm mass ratio of the raw materials when gradingthe gradation soil,which is medium sand: fine sand: clay=4:3:3, at this moment, thecoefficient of uniformity and curvature coefficients simultaneously satisfy. The designedgradation soil is well-graded.The test results about the maximum dry density and the optimum water content of thegradation soil is that the designed gradation soil is well-graded, The maximum dry density is2.03g/cm3, meeting the practical requirements of construction; in the range of8%to12%water content, dry density is more than2g/cm3, that means the designed gradation soil is notstrict with optimum water content, and it is useful to compaction test.The direct shear test result of designed gradation soil is that the cohesion of designedgradation soil is greater than medium sand and fine sand, less than clay, and the internal friction angle is about34.4°. That is to say that the gradation soil is easier to compact, andsimultaneously have a higher bearing capacity.Soak the compacted designed grading soil in water, and the compacted soil samplesgradually loose, meeting the repeated use requirement of compacted soil in the soil bin.Choosing experimental prototype to test, it has proved that the designed gradation soil alongwith soil bin both satisfy the requirement of the compaction and performance studies of theroller.