Study On Compaction Mechanism And Construction Technology Of Subgrade Filled With Highway Cohesive Soil

Fujian province is located in the coastal area of our country,most of its area,abundant rainfall,warm in winter and hot in summer;special geographical and climatic conditions that determine the regional distribution of a large number of cohesive soil,the differences between these clay filler engineering characteristics is large,in this kind of filler in the rolling process,the subgrade compaction difficult to achieve the requirements of the standard the phenomenon often occurs.The main factors affecting the quality of roadbed in-depth understanding and knowledge of clay subgrade engineering properties and construction process,requires the compaction mechanism and construction technology of clay subgrade for more in-depth analysis and research.Through laboratory tests on cohesive soil physical and mechanical characteristics,analysis of influence factors of clay subgrade strength and degree of compaction;and the combination of indoor compaction test,according to the different types of clay subgrade filler,make its full compaction curve,water saturation,internal relationship between the complete compaction curve and soil body,related the equation between the compaction curves established with cohesive soil physical and mechanical indexes;and according to the laboratory test and result analysis,put forward the best method of determining clay soil parameters within the scope of the specific content;to carry out field compaction test,verify the feasibility of compaction,the compaction and settlement detection method is proposed,the clay subgrade filling best the construction parameters,the related experimental data and research in different areas of Fujian province typical clayey soil subgrade test section,summed up the Fujian Province Optimum construction parameters of typical cohesive soil subgrade filling.The main work and conclusions of this thesis are as follows:(1)The optimum water content of the soil is dry tap CBR value,although higher,will meet the demand of our country standard,when water infiltration,the CBR value decreases rapidly,the degree of compaction will also decrease rapidly,resulting in the roadbed water stability and strength are not up to the requirements of the specification.It is suggested to fill subgrade in wet and rainy area,and control water content in the best moisture content of wet side roller compacted subgrade filling,which can better maintain the water stability and strength of subgrade for a long time.(2)Clay three different physical properties,increase the compaction work,will cause the soil compaction dry density constant pad increases,the highest water content ratio corresponding to the decrease of wm.From the whole compaction curve,when the compaction work increases,the whole compaction curve moves to the left and the top,at the same time,the best moisture content of compacted soil sample decreases,and the maximum dry density increases.In the humid area of compaction curve,the compaction curve under different compaction work is basically coincident,and it will not change because of the change of compaction work.(3)The degree of compaction and settlement rate parameter to control the compaction effect is good or bad,the compaction effect compared with big vibration beat the road machine than ordinary road rollers,two roller compaction effect is better than the upper and lower compaction effect,large vibration beat road machine in loose paving thickness is 60cm,the compaction effect is the best;And the loose paving thickness is 60cm,big beat vibration road roller the embankment to 93%and 94%and 96%,which are the best combination of rolling(4)Through the test section of the typical clay subgrade in different regions in Fujian province were analyzed the related research and test data,the different soil in Fujian Province,different rolling machinery,different thickness,the optimum combination of rolling compaction degree reached 93%and 94%and 96%.