The Mechanism Study Of The Consolidation Coefficient Of Soils Determined By Piezocone Penetration Test

The coefficient of consolidation is the most important parameter to calculate the distortion of the ground of soft clay. It is also the key parameter in ground reinforce design. For a long time it is tested in lab after sampling. The consolidation coefficient taken by this way has disparity compared with the real value in the location. It is inescapable disturbed by such series as sampling, transporting and testing.Thus, in order to get the in-situ consolidation coefficient, geotechnical engineers have searched for better testing methods in these years. Piezocone penetration test (CPTU) is a new in-situ testing technique for soils from 1980s'. With the function of measuring pore water pressure the probe can test the course that the excess pore water pressure dissipating with time. Getting the characteristic of penetration and consolidation of soils, it can calculate the in-situ consolidation coefficient of soils. The results get by CPTU are more really and closer to the real ground soils.However, the testing theories of CPTU are empirical and semi-empirical correlation. Until now the testing mechanism of CPTU is complex, and has not been get clearly. The application and development of CPTU was largely limited.The testing mechanism of the consolidation coefficient of soils determined by CPTU is discussed in this dissertation. A large CPTU model test in refashion clay was done to find the testing mechanism.Previous experiments, theories and methods about the mechanism study of CPTU have been broadly collected and fully analyzed in this paper. And the space axial-symmetric mathematic model of excess pore water pressure dissipation of CPTU has been built up based on the analysis of the penetrating character of CPTU. The basic consolidation theories of Terzaghi's and Biot's and their differences are discussed. According to the Terzaghi's theory, the mathematic model was resolved. And the calculation formula estimated the consolidation coefficient of soils by CPTU was gained. The equipments of model test, operation and calculation were introduced, and the results were compared with the test data measured by laboratory. Through more analyzing the...