Study On The Influence Of The Content Of Coarse Grains On Consolidation Characteristics For Chuanxi Talus Mixed Soil

The consolidation characteristic of soil is an important research content in soil mechanics. The mechanical properties of soil are mainly deformation and strength properties. The consolidation deformation of soil is an important problem that needs to be considered and studied in the construction of modern engineering. It has an important influence on the seepage, stability, settlement and so on. At present, there are many researches on the consolidation tests in the civil engineering field. The consolidation theory has been mature, but there are not many researches on the large-scale consolidation tests of coarse grained and fine grained mixed soils. In the complex geological environment of the West Sichuan exist widely a kind of talus mixed soil, with many origins, various compositions, multiple gradations, and complex particle morphology and environment sensitivity. In this paper, the large-scale consolidation tests of the Chuanxi talus mixed soil are carried out. The influence of the content of coarse particles, the ratio of initial void ratio and initial water content are analyzed. In this paper, the relationship between the compression modulus Es and the content of the coarse grain is drawn through the analysis of the experimental results and finally determine the influence of the content of coarse particles on consolidation characteristics of the Chuanxi talus mixed soil. The experimental study on the large scale consolidation of the Chuanxi talus mixed soil are analyzed with the natural gradation soil.In the experimental study, the three kinds of mixed soil are all treated in three ways:no coarse particles, the coarse particles above 20mm and coarse particles above 5mm are eliminated. Through the experimental study, the paper arrives at the following conclusions:1.There’s a big difference between the three kinds of mixed soil in the state of physical properties. The NO.1 mixed soil’s natural density is the smallest, and the water content is also the smallest. This is mainly related to the high content of kaolinite in mixed soil. In particle content field, NO.3 mixed soil’s content of cobble and boulderet were the highest. And the NO.1 mixed soil’s content of the number of 0.075mm<d<5mm particle size of mixed soil was the highest.2.The impact transitional zone of the content of coarse particles larger than 5mm is 30%-40% on the consolidation characteristics of the Chuanxi talus mixed soil. With the increase of the content of the coarse particles, the compression modulus of the soil increases and the change of void ratio decreases, the soil is difficult to compress. When the coarse particle content of more than 5mm is less than 30%, the fine particles play a major role, the soil exhibits fine particle properties, and the compressibility of the soil is high. When the coarse particle content of more than 5mm is more than 40%, the skeleton of the coarse particles play a major role, the soil has obvious coarse grain properties, and the compressibility of the soil is significantly reduced. When the content of coarse grain more than 5mm is between 30%-40%, the coarse particle and fine particle together play a role, the compressibility of soil is also between them.3.The mineral composition of the soil has an influence on the consolidation behavior of the soil, especially in the case of coarse particles below 5mm. The NO.1 mixed soil contains a large amount of kaolinite, so it has high strength and low compressibility. The NO.2 mixed soil and the NO.3 mixed soil have more close mineral composition, so their compressibility are closed in the case of coarse particles below 5mm.4.The effects of different initial void ratios (e0=1.1, e0=0.9, e0=0.7) on the consolidation characteristics are found in the experiment. The lower the initial void ratio, the smaller the unit settlement, and the lower the compressibility of the same mixed soil.5.The effects of different initial water content (w0=15%. w0=17%、w0=20%) on the consolidation characteristics are found in the experiment.the lower the initial water content, the smaller the unit settlement, and the lower the compressibility of the same mixed soil.