Evaluation of compaction weak areas based on continuous compaction quality detection

Evaluation of compaction weak areas is an important part in railway subgrade compaction quality control and acceptance. In view of the disadvantage that the existing evaluation system of compaction weak areas does not include the characteristics of measurement value, area and spatial distribution of weak areas, the concept of "compaction volume" was proposed and the weak area index and area comprehensive evaluation indicator U was defined. The nearest neighbor index method in geo-statistics was introduced to determine the weak area spatial distribution evaluation index R. Using the test data of subgrade test section of Shanghai-Kunming high speed railway, a comparison was made on the evaluation results between the existing compaction weak area evaluation indicators and new indicators U and R. The results proved the applicability and advantages of U and R when the two indicators evaluated the compaction quality of weak areas together. The acceptance target values of comprehensive indicators U and R were determined to be 1% and 0.5 respectively. The results provided a new reference for the evaluation system of the continuous compaction quality of railway subgrade.