Application Of Mixed Programming In Site Engineering Shear Wave Velocity Measurement

As an in-situ test method, shear wave velocity test has the advantages of high construction efficiency, simple operation and convenient data arrangement. In the engineering investigation and seismic design, it is of great significance to determine the thickness of the site coverage, determine the type of site, estimate the site predominant period, analyze the site of the earthquake damage potential, calculate the stiffness of the foundation and test the effect of ground treatment. It also can calculate the soil Poisson’s ratio, shear modulus, elastic modulus and damping coefficient by the shear wave velocity test, so as to provide basic data for the seismic response analysis and dynamic analysis of the foundation.At present, there are three main methods of measuring shear wave velocity, including single-hole method, cross-hole method and surface wave method. Cross-hole method tests require a large number of drilling, high construction efficiency and low cost; surface wave method is seldom used in project because of its complex equipment and data processing; while single-hole method can be performed just with a borehole,simple preparation and equipment is easy to operate compared to the others, therefore, the single-hole method is most widely used in engineering.However, the single hole method has a problem of calculation accuracy, which is pivotal influenced by the judgment of first arriving time of shear wave. Adopting artificial identification to identifying the first arriving time of shear wave in traditional,with the increase of drilling hole depth, the influence of site noise,which increase difficulties in arriving time difference identification,make great error,low efficiency of artificial identification.The cross-correlation function analysis of shear wave first arriving time can solve the above problems effectively, and using Fortran program a kind of automatically calculating shear wave velocity, while Fortran used in engineering measurement adversely due to its poor operation.Based on the above considerations, the principle and method of mixed programming with C# and Fortran are produced in detail in this paper. Compile the Fortran program of calculating shear wave velocity to generate the dynamic link library and call it using c#, to accomplish the development of software for calculating and analyzing shear wave velocity by single-hole method, which is based on the C# interface development platform and uses Fortran as the kernel of computation. So many functions can be achieved, such as calculating the time difference automatically, generating shear wave velocity structure automatically, calculating the equivalent shear wave velocity and the thickness of the covering, dividing site categories, estimating site excellence cycle, completing test reports automatically etc. It is convenient for the testers to operate, can improve the test efficiency and calculation accuracy of single-hole method, and has the important practical significance in the engineering field, that combining the mixed programming of C# and FORTRAN with shear wave test by the single-hole method, and realizing the visual processing of data based on the characteristics of good human-computer interaction.