Influence of Mix Ratio on Shear Strength of Tabia

Nine groups of mix proportions of tabia are proposed by complete test design method with 2 factors and 3 levels, and compaction test of each group is carried out. Shear strength test blocks are made according to the maximum dry density and the corresponding optimum moisture content of each group, and maintained on standard conditions for 7 days and 28 days respectively for shear strength test. The shear strength index of cohesion and internal friction angle of each test group are obtained. The following conclusions are obtained through range analysis and trend analysis. The influence of sand in tabia with 7 days and 28 days on the internal friction angle is greater than the influence of clay; the influence of sand with 7 days on cohesion is greater than that of clay, while influence of sand with 28 days on cohesion is less than that of clay. The mix ratio of tabia that reached maximum internal friction angle is lime: clay: sand=1:4:5, and the mix ratio of tabia that reached maximum cohesion is lime: clay: sand =1:6:3. For 7 days, taking the vertical pressure of 196 kPa as critical value in magnitude, two kinds of mix proportions with maximum shear strength of tabia can be obtained respectively. The research results may provide reference for rational selection of mix proportion of tabia in engineering application.