| It is an effective way of resources reuseing to use tailings for damming in mine production. The effect of consolidation of tailings is directly related to the construction of the tailing reservoir, including the effects of formation conditions of dry beach, dam construction and the stability of the dam. Therefore, it is great significant in studying how to accelerate the consolidation and deposition rate of the tailings and increase the intensity of dry beach in tailings engineering. In this paper, taking the project about damming with high-density tailings in Meishan of Nanjing as an example, making a preliminary study on filtering and damming with the high-density tailings and the methods to accelerate the consolidation and deposition of the tailings, by using the method of field test, laboratory geotechnical engineering tests and numerical calculation combined with practical engineering.The main work and achievements of this paper are as follows:(1) Making the conclusion that the high-density tailings can be used to dam after filtering by studying the feasibility of damming through the filter test of high-density. Doing the calculation about the consolidation of tailings at 50m of dry beach under the condition of high-density discharge, it shows that the consolidation of the tailings is not complete with this discharge mode, the static stability of three-level sub dam does not meet the engineering requirements.(2) Under the situation that tailings not completely consolidation with the way of high-density discharge, throwing soilbags for compaction to strengthen of dry beach considering the unique engineering characteristics of soilbag, getting the section shape and depth of the compaction after calculation. On the basis, the static stability of the dam is verified, the results show that the dam is safe and verify the feasibility of compaction to reinforcement of dry beach.(3) Doing the tests of sluice with high-density discharge and low-density discharge after dilution in the reservoir in the field. Ensuring the flow of the tailings is consistent during the test process, after a period of time, sampling and analysising the tailings at the same position of sluice and reservoir. Through the analysis of the particle composition, it indicates that the effece of particle separation with low-density diacharge of the tailings after dilution is better than the high-density discharge directly, the higher content of coarse particles (diameter greater than 0.0075mm) in the area less than fifty meters of the dry beach. Calculating the consolidation of the tailings at 50m and the stability of the dam with high-density and low-density discharge, the results show that the seepage line of the reservoir buried deeper, the consolidation is basically completed of the tailings and the dam is relatively safe. Providing a strong basis about the study on the method of high-density transportation and low-density discharge of the tailings reservoir.(4) Low-density discharge of the tailings after dilution, the regional distribution of the tailings sand is increases, the saturated loose sand is prone to liquefy under the earthquake or other virbration. Trying to make it liquefy in advanced, then the soil particles rearrange and become compacted after liquefaction, it is good for further strengthening and damming. Selecting different vibration amplitude, virbration frequency and consolidation ratio to do the dynamic triaxial tests to study the liquefaction characteristics of the tailings sand. The tests results show that:the vibration amplitude is bigger, the time of liquefaction is shorter, the dynamic strength of tailings sand increases with the decreases of frequency, the growth rate of the dynamic pore water pressure increases with the increases of frequency. In addition, the dynamic strength of tailings sand increases with the increases of consolidation ratio. It provides reference for the experimental research on liquefaction in advanced and reinforce in the field. |
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