Study On A Technique For Detecting Compactness Of Soil-Rock Mixture Subgrade Based On Static Load Test

As the highway construction extends over mountainous distinct, soil-rock mixture subgrade, one of the highway subgrade forms, has become more universal in the day. To guarantee the rapid construction and filling quality of soil-rock mixture subgrade, it is inevitably necessary to develop speedy and reliable new detecting technology for compactness of soil-rock mixture subgrade. However, the traditional water (sand) replacement method or wave method remains in use for detecting compactness of soil-rock mixture subgrade at present, and there are dificiencies and limitations since these above methods do much damage to the subgrade or the accuracy of these methods is poor or the efficiency is low, which are unable to meet the requirements of soil-rock mixture subgrade rapid construction. Therefore, the research work about detecting compactness method was carried out comprehensively combining the research project of detecting compactness of soil-rock mixture subgrade sponsored by Highway Administration of Hunan, and a new technique for detecting the compactness of soil-rock mixture subgrade will be developed, this new method has been of great theoretical and practical engineering value.On the basis of comprehensive analysis of the present compactness detecting technology of soil-rock mixture subgrade, firstly, combined with the research on deformation under the action of load and compactness mechanism of soil-rock mixture subgrade, an idea of step-by-step loading and the Boussinesq's theory about semi-infinite space under concentrated or distributed load are introduced, then the calculation model for detecting compactness of soil-rock mixture subgrade was established by thoroughly investigating the models described the change of porosity ratio and deformation modulus respectively, which lays a firm foundation for the development of detecting compactness of soil-rock mixture subgrade based on the principle of static penetration test. Secondly, the applicability of the major components (such as the shape and size of probe,etc.) of detecting equipment of compactness was deeply discussed through interior models test and in-situ static penetration test, which provide the reliable basis for the design of detecting equipment. Thirdly, combined with the development of detecting equipment of compactness and the study on analysis model for detecting compactness of soil-rock mixture subgrade, a new technique for rapid detecting compactness that can answer the needs for practical detecting engineering was developed preliminarily. Finally, the feasibility and rationality of this technique was identified by the computation of the result of in-situ test and through the comparative analysis of compactness consequences gained by this technique and traditional method, which perfects the method and theory of detecting the compactness of soil-rock mixture subgrade.