Measurement software DOWNHOLE

calculationgraphicseismology

The downhole seismic method (DH) measures the time taken for the P and S waves to move between a seismic source located on the surface of the ground, and the receivers, placed inside a borehole. Once entered the information for the project, the depth reached and the travel times, we can get: • the distances from source to receiver • corrected travel times • speeds of P and S waves • some important geotechnical parameters • the travel time graph with seismic layers from which can be determined the average velocity in each layer, some average geotechnical parameters and VS30 • the graph of P and S waves interval velocity and definition of seismic layer • graphics relating to geotechnical parameters, derived for each interval • the stratigraphy of the borehole • the final report The import of SEG2 files ensures to this software a high compatibility with the working tools. INTERPRETATION WITH DIRECT METHOD With the direct method, initially, must be corrected the travel times (t) measured along the source-receiver paths to take into account the inclination of the path of the waves and then realized the chart tcor-z, for both P waves and S waves. Thus the average speed of seismic waves in homogeneous layers of soil is represented by the inclination of the line segments along which are aligned to the experimental data. Once the seismic layers are graphically obtained, we get the average density, from the speed and depth, Poisson’s ratio, shear deformation modulus, oedometric modulus, Young’s modulus, bulk modulus, VS30.