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A time feld search method for AE source location with a regional velocity model

Wu Shunchuan, Gan Yixiong, Hampton Jesse, Gutierrez Marte, Lu Mingjing, Huang Xiaoqing

Acta Geophysica

2020

Vol. 68, no. 5

1335--1344

A time-feld search method was proposed for AE event source location, combining the grid search method and the database technique. Theoretical process was given, and laboratory hydraulic fracture stimulation experiments under true-triaxial confning stresses were performed to prove the practicability of the method. A regional velocity model with variable wave velocities and directionality was required to ft observations. The location results showed that time-feld location method obtains the global optimal source location solution with a relatively high efciency and accuracy.

The role of geophysical ERT method to evaluate the leakproofness of diapragm wall of deep foundation trenches on the example of the construction of retail and office complex in Lublin, Poland

Pacanowski G., Czarniak P., Bąkowska A., Mieszkowski R, Welc F

Studia Quaternaria

2014

Vol. 31, Nr 2

91--99

This paper addresses the problem of assessing the leakproofness of the bottom of a deep foundation trench, secured by cavity wall, using geophysical methods of electrical resistivity tomography. The study was conducted on a large construction project in Lublin, in a place where there are complicated soil-water conditions: the groundwater level is above the proposed depth of foundation trench, the subsoil is heterogeneous, and there are karsted and weathered carbonate sediments with confined aquifer below the bottom of the trench. A hydraulic fracture occurred at the bottom of the trench during the engineering works, which caused the water flow into the trench. In order to recognize the soil-water conditions the first stage of geophysical measurements of electrical resistivity tomography (ERT) was made. The applied methodology allowed to determine the extent of the hydraulic fracture zone within the bottom of foundation trench. In order to assess the leakproofness of Diaphragm Wall the geophysical ERT measurements were repeated (stage 2) A clear reduction in the value of the electrical resistivity of soils in the area of hydraulic fracture was caused by clay injection. The results of ERT measurements are discussed and graphically presented.