| Foamed lightweight soil referred to as FCB,is a new type of light and porous civil construction materials,it is made of raw material soil,air bubbles,cementitious materials according to a certain proportion of mixing,with the advantages of light weight,bulk density and strength adjustable,durability,construction convenience,high mobility,thermal insulation and so on.In soft ground treatment,highway widening,vehicle dumping,abutment back fill,landslides,and a steep section of embankment and retaining wall back filled soil,cavity filling and pipeline backfill has played a significant outstanding performance in practical engineering,bubble mixed light soil have broad prospects for engineering applications in the future because of its low cost,simple preparation,convenient construction,green environmental protection and other comprehensive advantages.Around the properties of the heat preservation and heat insulation of foamed lightweight soil,not only the effects of bubble content and freeze-thaw cycle on the internal temperature field distribution of lightweight soil and its variation law were analyzed by using the single factor control variable method and temperature sensor through laboratory experiments,but also the thermal insulation performance of bubble mixed light soil was assessed in this article,which was in the basis of summarizing the research results at home and abroad.The theory of heat conduction problems and finite element physical calculation equations was introduced,and by using ABAQUS software combined with two cases,the thermal stability of light-weight soil was analyzed under different working conditions of modeling.Finally,the optimizing layout of lightweight soil subgrade bed was given according to the results of numerical simulations of the second case.The conclusions are as follows:(1)The temperature at different locations in the light soil decreases first and then increases during monitoring time when the number of freeze-thaw cycles is same.After freezing and melting,the temperature difference of the foamed group is smaller than that of the blank group,and the more the bubble content is,the smaller the temperature difference is.Therefore,within the test range,the effect of improving heat preservation and insulation of lightweight soil increased by the increase of the bubble content.(2)Under the same air bubble content,the internal temperature of light soil decreases first and then increases with time.The more the freeze-thaw cycle is,the bigger the temperature difference at different locations in the lightweight soil will be.Within the test range,the time which needed to reach zero degree inside the foamed lightweight soil increased with the increase of the bubble content.When the bubble content was up to 500L/m~3,the final temperature after the freeze-thaw was still above zero degree,which was the best group for heat preservation and insulation within the test range.(3)Without water inside,the final stable temperature of the bubble content group was significantly higher than that of the blank group,and the percentage of temperature increasement increased with the increase of the bubble content;The final temperature difference of adjacent sensors also increased as the bubble content was increased.When the bubble content is 500 L/m3,the final temperature difference of the sensor is the highest,which is the best group for heat preservation and insulation within the test range.(4)The ABAQUS software was used to calculate the temperature field of different cases of geotechnical structures in water conservancy projects,the temperature distribution and variation rules was analyzed,and the calculation results and analysis of the two cases showed the excellence of lightweight soil in heat preservation and insulation.According to the calculated results of case 2,which were in good agreement with the actual monitoring data,the optimal arrangement plan of lightweight soil cushion was proposed soil cushion was put forward for this practical engineering case. |
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