Numerical Simulation of Waterproof Curtain Leakage Disease of Soft Soil Foundation Pit Using Three-Dimension Resistivity Method

摘要

The leakage disease of waterproof curtain is one of the main challenges which will cause the instability of soft soil foundation pits.Conventional detection methods can only indirectly reflect the local quality of waterproof curtain,which cannot evaluate the overall quality accurately.This paper describes a 3-D high density resistivity (HDR) method for the leakage detection of waterproof curtains of foundation pits.We use 3-D electrical field theory and program the calculation codes by means of numerical simulation technology.At the same time,we give a crossing-curtain type of 3-D acquisition array to calculate the apparent resistivity,and then the RES3DINV software is used to image the true resistivity underground.According to the typical leakage types of waterproof curtain,we calculate their apparent resistivity value using five kinds of electrode arrays and give their 3-D slices using Voxler software.Results show that the 3-D resistivity method can depict the leakage position efficiently,and the WENNER array owns the highest signal intensity and resolution,while the Pole-Pole array has the lowest resolution and fails to locate the leakage points.We also find the environmental electrical noise has influence on the inversion results,but due to the enough electrical information of the underground media,we can still find the leakage position clearly for the strata with high water saturation and low resistivity.