Experimental Study On Consolidation Of Peat Soil In Dali Area Of Yunnan

As a special soil,peat has a wide distribution in the world.Because of its high water content,high organic matter content,high void ratio and compressibility,it has different properties from soft.The soil is not exactly the same,and in the existing research,it shows the characteristics of long consolidation time and large creep.As China's infrastructure investment in the southwest region is further increased,the construction of expressways and high-speed railways will inevitably involve peat land foundations,and how to properly dispose of such special land'bases is urgently needed for research.At present,domestic systematic research on peat soil has just begun,and the consolidation test is still carried out by standard methods.Some foreign researchers have adjusted the test method for the factors affecting the consolidation and obtained more accurate test data.In view of this,this paper relies on the National Natural Science Foundation project "Study on the consolidation mechanism and settlement calculation method of peat soil foundation under embankment",and the typical peat soil in Dali area of Yunnan Province is tested on the basis of its basic physical and chemical properties.In the consolidation test,the effects of experimental control conditions on the consolidation characteristics of peat soil,such as ambient temperature and degree of contact with oxygen,were investigated.The control conditions during the unidirectional consolidation test of peat soil were proposed to reduce the consolidation test.The method of "disturbing" the environment in the process,and on the basis of this,explores its consolidation characteristics and draws relevant conclusions.Firstly,the influence of temperature on the consolidation process of peat soil is explored.By comparing the low-stress and high-stress conditions,the trend of the compression per unit hour of the sample with different organic matter content in the consolidation process is analyzed.The effect of peat soil consolidation test.The results show that regardless of low stress or high stress,temperature has a great influence on the consolidation deformation of peat soil,and this effect increases with the increase of organic matter content.Secondly,under the condition of controlling the temperature of the test environment,the inhibition effect of thymol solution on the decomposition of organic matter in peat soil was investigated.By comparing the loss on ignition and the total nitrogen(TN)content before and after the test in different consolidation time test groups,It was found that the use of thymol solution with a concentration of 1%for 7 days or 60 days can effectively inhibit the decomposition of organic matter during the consolidation of peat soil and reduce the accelerated decomposition of organic matter caused by contact with air after soil samples are taken out;In the case of controlling other variables,the effects of the two test methods of immersion and spray were compared.By comparing the main parameters such as the completion time of consolidation,the consolidation coefficient and the secondary consolidation coefficient,it was found that the immersion method was reduced.The decomposition of organic matter in peat soil is more effective.Finally,the consolidation test was carried out under the optimal control conditions obtained in this paper,and the consolidation time under 800 kPa load was extended until the deformation was less than 0.01 mm/d.The consolidation characteristics of peat soil were explored and the corresponding conclusions were obtained.At the same time,the main reason for the third consolidation stage is analyzed.The primary and secondary consolidation ratios under the load of 800 kPa are about 1.2,and the ratio of Ca and C,is 0.063,which has a high engineering reference value.