| In Hainan province, along with the development of international tourism island, the projects of construction are expanding constantly. Compared with other general mechanical and chemical processing method, dynamic compaction method has the merits of simple equipment for construction, fast construction, less construction cost and remarkable effect for strengthening, etc. So it is widely used. Lots of theoretical researches were carried out in recent years, but they were usually focused on studying of mechanism and calculates influence depth of dynamic compaction, it rarely studied on bearing capacity and deformation modulus of dynamic compaction foundation. Up to now, there are no systematical theory or the agreed opinions for the designing and application of the dynamic compaction and the degree of improvement for dynamic compaction is left to be determined by way of testing after treatment. Therefore, in view of the particular condition of the coastal area in Hainan, researches, aim to the application on the testing method for bearing capacity of dynamic compaction foundation, have important theory and practical significance on promoting the level of application.Firstly, in this paper, analyze on the calculation formula and the principle of the method, such as searching the norm, theoretical formula, spot testing, for determination of the bearing capacity of the foundation that treated by dynamic consolidation, obtain that whether using the method of searching the nonn nor theoretical formula to evaluate the bearing capacity of foundation after been treated has certain unreliability. Combined with the loading test the dynamic penetration test, then establish certain related equations, can both convenient and accurate determine the bearing capacity.Secondly, through the theoretical analysis, cone dynamic penetration test doesn’t need to correct the stem side friction and the underground water level except the stem length. Based on the comparison test on Wenchang coastal tourist road projects, it is obtained that:the standard penetration test blow count obtained respectively by rotary drilling and percussion drilling has a relationship of N回=1.183冲； the degree of reliability obtained by 《The Rock Soil Engineering Reconnaissance Specification》 is higher than probability statistical method.Thirdly, through some test carried out on the project of Sanya overseas talent development center, it showed that:effect caused by the size exists in the plate loading test, the plate is wider, the test result is bigger and the discrete is smaller. If the results obtained in width1m as standard, the correction coefficient is respectively1.22,1.16,1.08, when the board width is0.5m,0.707m,0.866m; the time required by the rapid method is half of the slow method, however, the rapid method which is only suitable to be used to determine the foundation bearing capacity value can not be used to determine the ultimate bearing capacity. Under the action of pre-loading and not pre-loading, the bearing capacity of the foundation treated by dynamic compaction, are very close. So, for general engineering, pre-loading can not be carried out.Finally, the correlation between the in-situ test are analyzed on three projects:tufuwan in Lingshui, seaside tourism highway in Wenchang, overseas talent development center in Sanya, the equations about using the number of hammering to ensure the bearing capacity of foundation are concluded. Summarizes the three equations, the equation which applicable for the foundation treated by dynamic compaction in the coastal areas of Hainan is showed that:... |
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