Research On Influence Of Moisture Content On Test Index Of Subgrade Compaction

The moisture content has an important influence on the compaction quality of the roadbed.Subgrade fillers that are not at the optimal moisture content will cause various problems of uneven compaction during the compaction process.The quality of subgrade compaction is mainly reflected by the compaction test index.Therefore,it is extremely important to study the influence of the moisture content on the compaction test index.This paper analyzes the influence of different water content on the subsidence of the same type of soil through indoor experiments;through a high-speed railway field test,for the group A and B roadbed fillers,the conventional compaction index test and the continuous compaction index test were separately conducted The test indicators include: water content w,foundation coefficient K30,dynamic deformation modulus Evd,and vibration compaction value VCV.Through the collected data,the correlation between water content and conventional compaction test index and continuous compaction test index is analyzed,some rules are summarized,and the theory of water content change value as compaction test index is proposed.The main research contents are as follows:(1)Through laboratory tests,it can be concluded that as the pressure increases,the cumulative subsidence of the soil body with the increase of pressure becomes smaller and more stable,so the water content has an important influence on the conventional detection index.(2)For the A and B group roadbed fillers with different water content in the same location,the on-site simultaneous detection test of conventional compaction test index and continuous compaction test index was carried out,and the test results under different water content were compared and analyzed to obtain vibration The relationship between the compaction value VCV and the foundation coefficient K30 and the dynamic deformation modulus Evd determines that there is a good correlation between the conventional compaction test index and the continuous compaction test index at different water cuts.(3)Based on a large number of subgrade continuous compaction testing data,the collected data was statistically analyzed,and it was concluded that when the site construction was 30 ℃ ～ 35 ℃,the packing of group A and B subgrade fillers had been filled before the compaction operation.After the 5 mm sieve,when the water content is 1% to 1.5% higher than the optimal water content,that is,6.3% to 6.8%,the roadbed is more likely to be compacted.At the same time,the water content change value and the continuous compaction detection value are less affected by the subgrade soil particles and have a stronger adaptability.Therefore,the preliminary theory of using the moisture content change value and the vibration compaction value VCV as the compaction quality detection index is proposed.