| As the main building material of the earth-rock dam, the mechanical properties of the rockfill material have a decisive impact on dam safety. Currently rockfill material is widely used, the largest particle size is generally 600-800mm, in Shuibuya, Hongjiadu, Sanbanxi and other projects, the maximum size of particles reach 1200mm. But, due to the restrictions on the size of test instrument at home and abroad (the maximum diameter of the sample is 300 mm, corresponds to the biggest diameter of the rockfill material is 60 mm), only after a large proportion of the scale, the experimental study of the strength and deformation characteristics of rockfill can be doing, the differences of rockfill strength and deformation characteristics in the indoor test results and the actual engineering caused by scale is still unknown, and it is a big problem must be considered and difficult to overstep, so the high earth-rockfill dam safety evaluation is seriously restricted. To solve this problem, professor xian-jing kong of dalian university of technology, with tianshuihongshan testing machine LTD and Dalian ship shipbuilding heavy industry LTD, developed the ultra large static/dynamic triaxial apparatus (specimen diameter is 1000 mm and 800 mm), With the early developed large (sample diameter is 300 mm) and medium triaxial apparatus (sample diameter is 200 mm), they constitute the multi-scale test platform of the material mechanics properties and constitutive model research of high earth rockfill dam. They can be used to systematically study the effect of scale effect, (scale effect of dilatancy, particle breakage mechanism, the critical state characteristics, deformation modulus and strength characteristics etc.), and solve the scientific problems about the rockfill constitutive theory, provide theoretical and experimental basis for the static and dynamic numerical analysis and safety evaluation of high rockfill dam. So that, this studies abour ultra large triaxial apparatus sample molding technology in this paper is great application value.In the triaxial test, the sample shape is a key link. It determines that the test successes or not. For ultra large triaxial test, because of the size of rockfill particle sample and grain increase significantly (the quality of one sample is about 3.5 t, maximum particle size reachs 200 mm), it brought a series of difficult to sample molding:traditional vibration compaction method is difficult to achieve control of density, and has a low working efficiency; the traditional bearing membrane tube design concept will lead to heavy component, moving, installation, and removing have a low efficiency, and disturbance sample easily; the outside of the latex film sample size is too large, processing is very difficult, the success rate is very low. In addition, it is necessary to develop the multiple large auxiliary equipment (such as operation platform, vibrating screen, mixing plant, etc.).Based on the experience of the different size triaxial test sample molding accumulated by the research group for many years, there explore new methods of sample molding, to solve the difficulties in large triaxial apparatus sample molding. The main work includes:(1) Through test vibrator and battering ram compaction density, determining the feasibility of the scheme, and the existing equipment reform to apply to the ultra large triaxial test.(2)Using SolidWorks software rendering 3d components and ancillary equipment, and testing the assembly repeatedly, developing the membrane tube makes by aviation aluminum and movable multilayer operation platform for the sample moulding of the ultra large triaxial apparatus.(3)Through the 3d simulation of the sample moulding process, summarize the molding process for the sample of the ultra large triaxial apparatus and the matters needing attention, and provide the reference for compiling geotechnical test code relates to the sample of the ultra large triaxial test. |
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