| The method of soil replacement is often adopted during the construction of expansive soil subgrade in west area, that resulted in serious soil erosion, damages to ecological environments along highways, and engineering investment increasing greatly. The three indices for classification of expansive soil used as filler are the key and core of the physical treatment technique which could radically solve the problems. But any new ideas can be widely accepted that always need go through a process, when they appeared, and the process may be quite long. New ideas from any work proposed to be receive promotional applications, often require a long process, undergo practice, theory, and then the test of practice and continuous improvement. To speed up the process, this dissertation is combined the Bailong expressway which is constructing as research background and the problem which Baise expansive soil used in the construction is urgent. This paper carried out engineering applicability of index for classification of expansive soil filler and CBR rapid measurement research.Test on soil properties, strength and deformation of road performance were performed for three kinds of expansive rock/soil in Bai-Long Expressway. In terms of testing results and the new classification criteria of expansive rock/soil used as embankment filler determined by modified CBR strength, CBR swelling rate and consistency, it is concluded that the indices for the three kinds of expansive soils all satisfy the requirements. Therefore, the Bai-se expansive soils can be directly used as embankment filler. According to the testing results of soil properties and the principle of physical treatment technique combine with partial condition of the project construction, a technology with both embankment sides enveloped by non-expansive red clay and a filling method like"sandwich"were utilized. The NO.1 expansive soil having the poorest engineering behavior among the three kinds of soil sample was selected to fill the embankments of ZK176+135~ZK176+410 in Bai-Long expressway respectively. And consumption expansive soil more than 60,000 cubic meter altogether. This filling embankment has good quality from the results of following test detection for sugared construction. Accordingly, the engineering applicability of the index for classification of expansive soils as embankment filler is verified by the laboratory tests and practical projects. The road performance testing of excavated expansive soil should be performed to determine the fillers'classification and filling and abandoning plans for the embankment construction. However, the soaking periods of 4 days for CBR strength is consuming time when a large amount of CBR testing should be carried out due to the different characteristics of expansive soil at various positions. It may extend the construction period, which is disadvantage for the generalization of new treatment technology for expansive soil as embankment filler. Therefore, it is necessary to research the rapid measurement method to predict the CBR strength and swelling ratio. In this paper, a large amount of CBR tests on specimens with various water contents were performed to achieve the effect of soaking periods. The grey theory with weighted average first-order weakening buffer operator GM (1, 1) was introduced to use the testing results of soaking for 1 day to predict the CBR indexes for soaking 4 days. The prediction accuracy is one-level. Therefore, the rapid measurement method of modified CBR for expansive soil filler was presented.The rationality and engineering feasibility of three indexes for embankment filler were demonstrated and the rapid measurement method for CBR indexes was established to promote the generalization of new physical treatment technology of expansive soil embankment.
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