Abstract
The effective detection of layered roller compacted subgrade quality is the key of road engineering quality control. The traditional sand filling compaction method belongs to random sampling point detection method, and it is not easy to detect the subgrade compaction condition below the sand filling pit. Based on the summary of the current domestic and foreign subgrade detection technology, this paper innovatively combines the geological radar method with sand filling method, and through the fixed point detection method. The results show that the traditional sand filling method can directly and quantitatively reflect the compactness of sampling points, while the geological radar can realize the continuous detection, and can judge the compaction layer from the loose state to the interlaminar line after compaction through the geological radar image At the same time, the GPR can identify the under compacted area in the subgrade compaction layer and reflect the overall compaction effect of the subgrade. The detection method of combining the GPR method and sand filling method has obvious technical advantages in the subgrade quality detection.
Highlights
As the most commonly used control index of subgrade compaction effect, the evaluation index can be obtained through a variety of technical methods, which is mainly divided into two categories: damage detection and nondestructive testing
Through the investigation and field test, it is found that the nuclear density meter method, ring knife method, sand filling method and other destructive testing methods can be used to measure the compaction index of subgrade more accurately, the testing process is often random sampling test, and the results are random, so it is difficult to make a comprehensive evaluation of the compaction effect of Subgrade in the field; while the wave velocity method, geological radar method and other nondestructive testing methods are used the method can quickly and comprehensively measure the change of stratum properties, it is difficult to obtain quantitative compaction index
The sand filling method is a method to measure the volume of the test hole by using the clean and uniform sand with the particle size of 0.30-0.60mm, according to the principle that the unit volume weight of the sand freely falls into the test hole from a certain height remains unchanged, and calculate the measured dry density of the sample by combining with the water content of the aggregate
Summary
As the most commonly used control index of subgrade compaction effect, the evaluation index can be obtained through a variety of technical methods, which is mainly divided into two categories: damage detection and nondestructive testing. The following summarizes and analyzes the commonly used damage detection and nondestructive testing technology of subgrade
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