Study on influence factors of California Bearing Ratio (CBR) of expressway subgrade materials;

The similarities and differences of California bearing ratio(CBR) test requirements in America,Britain,Japan and China are analyzed;The test technology and proceeding are emphasized.

Aiming to avoid the occurrence of violating the requirements of the Specifications in strength for sub-grade, and to lower the engineering cost, the effective ways to improve the CBR values are studied in the paper, by which the author means improving the compactness of the sub-grade and mixing lime into the sub-grade materials.

Based on the current natural division,commenced from the demand of design and construction,authors put forward the highway design parameter of Xinjiang: the modulus of resilience of roadbed E_0 and CBR based on the third rank division.

To enhance the stability of soil filled in the roadbed of expressway,a high performance consolidating material(HPCM) was used to improve the stability of primary soil,and its performances such as CBR(California bearing ratio) value,compactness and expansion were investigated through a physical test,SEM(scanning electron microscopy) and XRD(X-ray diffraction) analyses.

To study the size effect of clay aggregate in Xuyi on water stability of improved filled material in a highway project in the north of Jiangsu Province,the California Bearing Ratio(CBR) tests were performed on eight types of samples stabilized by lime and CMSC firming agent which were added into clay with different grain sizes.