| Soil shear wave velocity is an important parameter of the dynamic property of soil. Study on shear wave velocity and its related aspects is one of the important subjects of the current research in the anti-seismic field of geotechnical engineering. The size of the shear wave velocity, not only reflects on the wave propagation medium capacity but also reflects the "hard and soft" soil extent, can be used to evaluate site soil type, soil cover, discrimination or liquefaction silt sand base to calculate dynamic shear modulus of the soil and seismic design of buildings, etc. Therefore, it is widely used in various important projects, top quality buildings as well as buildings with special technical requirements because of its great importance of theoretical value and practical significance of engineering.However, one of the most important characteristics of geotechnical material is the variability and uncertainty of the geotechnical parameters. Geotechnical, making the same soil under different conditions of shear wave velocity values have obvious differences due to soil characteristics, different geological origin and structure of the soil, is a very complex geological body. And in practical engineering applications, drilling depth, underground burying, the test methods, testers and other factors have a greater impact on the results of testing shear wave velocity, so that the same test point and several times of tests result in quite different shear wave velocity values. So if scientific estimate of shear wave velocity uncertainty is made, the actual soil shear wave velocity value and reasonable range will be reflected. Then the state of the soil will be more accurately reflected. Therefore, it’s a very significant project to study and analyse the uncertainty of the geotechnical parameters based on the available velocity data and the measured shear wave velocity data.Through Zhoushan Dinghai Area business park as shear wave velocity test site, several tests were conducted in the same borehole to obtain velocity data, and the following main work was carried out during uncertainty surrounding the shear wave velocity for statistical analysis:(1) A comprehensive and systematic analysis of the current situation of domestic and international research on shear wave velocity was carried out by a brief review of relative tests after consulting a large number of research materials and literature. shear wave velocity and the main problems in the course of the study there and future The main research directions.(2).This paper introduced main shear wave velocity testing instruments and their principle, including main technical parameters and testing methods, and also introduced several widely used instruments including the testing scope, testing methods together with their advantages and disadvantages.(3) In this paper, Zhoushan Dinghai Area business park as the shear wave velocity test site, several tests on the same drilling were conducted by single-hole testing method from bottom to top 1m spaced test points with a total of 35 groups of test samples to statistically analyzed their uncertainty of the test results.(4) This paper studies the following three aspects of the shear wave velocity uncertainty: the same depth of shear wave velocity uncertainty, main soil shear wave velocity uncertainty and the the equivalent shear wave velocity uncertainty. During the process of collecting date and making analyses, the 2c methods was used to check and analyze the frequency distribution curve of shear wave velocity to summarize the shear wave velocity eigenvalues under the three cases, and canculate the corresponding 95%, 85%, 75 % reference value of the upper and the lower volatility and relatively average, percentile by Direct calculation of percentile method.The obtained test results can be used to test the shear wave velocity field reliability. |
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