Large-Size Simple Shear Experimental Study On Coarse Grained Soil

Materials such as moraines, granulars, coarse grained soils have been applied widely in engineerings such as water conservancy, port, and traffic project, as large-scale industries, domestic buildings, and large-scale earth-rock dam are constructing. So the study on the coarse grained soils' engineering properties has attracted lots of attention from many experts. The indoor experiment is one of the important approaches to research the coarse grained soils' engineering properties. It is meaningful to select experiment instrument which has advantages in structure, transmitting force, operation, and its results are practical. In this article using the large-size simple shear, direct shear apparatus which is designed by Hohai University to research the coarse grained soils. Main contents and conclusions are as follows:1. Synthetically analyzing the research tendency at present of the coarse grained soils, especially about the grain breakage, comparing the triaxial apparatus, direct shear apparatus, simple shear apparatus, which are often used in the indoor experiment.2. Introducing the main components, structural principle and the operating process of the large-size simple shear, direct shear apparatus. Also earring out several group tests and comparing the results' differentials of simple shear and direct shear. Emphasizly analyzing the testing results of different initial dry densities and maximum sizes of the coarse grained soils.3. Through analyzing shear dilating based on the experimental data of the different maximum size and different initial dry densities coarse grained soils, it is find that dilation rate and shear stress ratio are linear relation, and previous research also indicates that dilation rate and shear stress ratio of the sand are linear relation, so it proves that the cohesionless soil relationship of dilation rate and shear stress ratio is consistent.4. Through analyzing grain breakage based on the experimental data of the different initial dry densities coarse grained soils, it is find that the breakage rate and the dilation rate are linear relation; from the energy angle, the dilation equations considering grain breakage and without considering grain breakage are established based on energy ratio principle, so the different parts of shear strength can be calculated; curves about the relationship of breakage rate and breakage energy show that it is reasonable to analyze the relationship between shattering ratio and shattering energy by dividing the curves into several parts.