| Along with the development of the west regions and the application of powerful country strategicwith strong civil aviation, the compaction quality became the key factor of holding foundation intensityand stability in high filled engineering with soil and rock mixture in construction of infrastructuralfacilities, specially in western airport construction. How to test the foundation compaction qualityeffectively had become a international technical problem in soil-rock filled engineering. Test means ofcutting ring method, sand replacement method, etc were usually adopted to test and evaluate theconstruction quality of high fill foundation. But it was difficult to test soil-rock foundation in large aerawith these traditional test methods because of furthermore human and material resources, low efficiencyand long period. To soil-rock mixture, there has been deficiency in research on compaction performance,static deformation, dynamic deformation properties and so on at present. The construction quality wasalways controlled by engineering experience or compaction times, which resulted in blindness insoil-rock foundation construction.The engineering properties of soil-rock mixture were decided by soil and rock. Compared with soil,rock material could be seen as rigid body. The compaction quality of soil-rock mixture would be assuredif compaction degree of soil was good. This thesis was supported by the National Natural ScienceFoundation (60879021) and Civil Aviation Agency of China Research Fund (MHRD07Z11). Based onwhich, the theoretical analysis and experimental research on macro shear wave velocity of soil-rockmixture were done. New method of evaluating compaction quality of mixture with compaction degree ofgap soil in mixture was proposed for the first time in compaction test of soil-rock foundation. Theanalysis model of correlation between macro shear wave velocity of soil-rock mixture and apparent drydensity of gap soil was built. By which the compaction degree of gap soil in mixture was calculated,then the compaction quality of soil-rock mixture was analyzed.The model of correlation between macro shear wave velocity of soil-rock mixture and shear wavevelocity of gap soil with different water content and different rock content was built systematically. Thevelocity of gap soil was analyzed effectively by application of macro shear wave velocity of mixture,which provided theoretical evidence for the establishment of evaluation system of apparent gap soilcompaction degree. This research was originated in the world. And the analysis theory of wave velocityof soil-rock mixture was enriched by the study.The new theory of test and analysis of the apparent compaction degree was proposed. The possible gap in mixture and the compaction state of gap soil were represented by dry density of gap soil. And thedry density of gap soil was defined as apparent dry density. By which, the basic concept and physicalmeaning were described more clearly. The computing model of correlation between macro shear wavevelocity of mixture and apparent dry density of gap soil was built. The evaluation criterion of apparentcompaction degree of mixture was established by experimental analysis of soil compaction state withgood strength and stability of mixture in different rock content, different water content and different rockgradation. By which, the theory of mechanics analysis of mixture was enriched.By analyzing variation mechanism of shear wave velocity with different soil type and differentwater content, The model of correlation between shear wave velocity of soil and dry density of soil wasbuilt. The influence of water content for shear wave velocity was analyzed around optimum watercontent. The change of shear wave velocity of soil was caused mainly by the change of soil shearmodulus and soil shear rigidity in different water content. The rule and mechanism of water contenteffects on shear wave velocity was revealed, and the evidence for improving the analysis precision ofsoil compaction degree with shear wave velocity was provided.By studying the change rule of poisson’s ratio in mixture with different water content, different rockcontent and defferent dry density, the distribution of poisson’s ratio in basic compacted soil-rock mixturewas confirmed. Sandy mixture,0.301-0.346; silt mixture,0.281-0.377; clay mixture,0.336-0.399. Thebinary function model of variation of soil-rock mixture with water content and rock content was built.The change rule of poisson’s ratio in mixture was revealed by this model. And the calculation model ofcorrelation between surface wave of mixture and shear wave of mixture was built. The theory of testwith shear wave velocity was enriched, and the scientific proof for studying apparent compaction degreeof soil-rock mixture with site surface wave test was provided.The technical problems in compacted quality control of soil-rock engineering can be solvedeffectively by the nondestructive test method of apparent mixture compactness and the theoreticalsystem of shear wave velocity analysis for mixture compactness which were proposed by a great numberof theoretical studies and experimental studies. The technical support for safety and durability of airfieldrunway in mountain aera was provided. The new method has great advantages in improving testprecision, quickening engineering schedule, saving test cost and so on. Therefore, it is of great economicand social benefit to popularize and apply this technology in high fill engineering of airport, railway andexpressway. |
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