scholarly journals Prediction of Soil Settlement using Numerical Modelling Based on Shear Wave Velocity Measurement

2021 ◽  
Vol 920 (1) ◽  
pp. 012043
Author(s):  
N F Bawadi ◽  
K C Teoh ◽  
A F Mansor ◽  
M M Nujid ◽  
M A Rahim ◽  
...  
Keyword(s):  
Numerical Modelling ◽  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Profile Analysis ◽  
Soil Medium ◽  
Frequency Responses ◽  
Soil Settlement ◽  
Shear Wave Velocity Profile ◽  
Non Destructive

Abstract The method of Spectral Analysis of Surface Wave (SASW) is a seismic method that consider as a non-destructive geotechnical technique to determine the soil profile based on the shear wave velocity profile by utilizing the dispersive characteristic of Rayleigh wave through the soil medium. The shear wave velocity was found to be directly proportional to the strength of the soil. In this research, SASW measurement had been proposed to predict the soil settlements using numerical modelling. The frequency responses from SASW were acquired for shear wave profile analysis using WinSASW software. Thus, the borehole information which near to the conventional pile method and SASW were taken as the reference of the study. In obtaining the correlated N-value, equation that developed from previous research was used with the reference of N-SPT value. Hence, the correlated N-values were carried forward to obtaining the bearing capacity of foundation. Meanwhile, the numerical modelling has been developed in PLAXIS software in obtaining the soil settlement. The prediction of soil settlements of Site 1, Site 2 and Site 3 that calculated by conventional equation and modelled using PLAXIS were 0.003mm and 0.001mm, 0.002mm and 0.004mm, 0.003mm and 0.004m respectively. Based on the result obtained, this research has shown the potential used of shear wave velocity in the prediction of soil settlement.

scholarly journals Study of VCM Improved Soft Soil Properties Using Non-Destructive and Destructive Techniques

Geosciences ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 300
Author(s):  
Diandri Fakhri Alditra ◽  
Susit Chaiprakaikeow ◽  
Suttisak Soralump
Keyword(s):  
Soil Properties ◽  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Soft Soil ◽  
Soil Improvement ◽  
Prefabricated Vertical Drain ◽  
Soil Settlement ◽  
Pump Pressure ◽  
Non Destructive

In Bangkok, the demand for housing is extensively high due to the city growing rapidly, so some swampy areas are filled with soil. A Prefabricated Vertical Drain (PVD) with the Vacuum Consolidation Method (VCM) is required to make the soil applicable for construction. However, it is difficult to monitor the soil strength during the process because the airtight sheet will be broken. This research aims to study the possibility of using the Spectral Analysis of Surface Waves (SASW) test to monitor the effectiveness of the VCM method and to study the development of shear-wave velocity over the consolidation period. Multiple instruments were installed on site, namely, vacuum gauges, settlement plates, and a piezometer, as well as a borehole to monitor the pump pressure, settlement, porewater pressure, and soil properties. Ten SASW tests were taken to measure the change in shear-wave velocity (Vs) over 7 months. The results showed an increment in the Vs along with increments in the settlement and undrained shear strength (Su), as well as a decrement in pore pressure during the consolidation period. The correlation between Vs and soil settlement was developed to predict the amount of settlement using Vs. These all indicated the potential of using the SASW method for soil improvement monitoring purposes.

Experimental Estimation of Shear Wave Velocity Profile Using MASW Method and Inversion Technique

2013 ◽  
Vol 300-301 ◽  
pp. 955-958
Author(s):  
Pei Hsun Tsai ◽  
Chih Chun Lou
Keyword(s):  
Genetic Algorithm ◽  
Velocity Profile ◽  
Dispersion Curve ◽  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Dispersion Curves ◽  
Real Parameter ◽  
Shear Wave Velocity Profile ◽  
Experimental Dispersion

In the paper the shear wave velocity profile is studied using the MASW test. The experimental dispersion curves were obtained from the signal process proposed by Ryden. Theoretical dispersion curve can be constructed by thin layer stiffness matrix method. A real-parameter genetic algorithm is required to minimize the error between the theoretical and experimental dispersion curves. To reduce the error of experimental and theoretical dispersion curve using real-parameter genetic algorithm is feasible. The results show that the soil layers of the study area can be modeled as a sandy fill overlaid on an underlying half space. Test results also show that the asymptotes at high frequencies of the fundamental mode approach the phase velocities for the fill of 190 m/s. The depths of weathered bedrock estimating from dispersion curves match well with that of borehole data.

scholarly journals Scholte Wave Dispersion Modeling and Subsequent Application in Seabed Shear-Wave Velocity Profile Inversion

2021 ◽  
Vol 9 (8) ◽  
pp. 840
Author(s):  
Yang Dong ◽  
Shengchun Piao ◽  
Lijia Gong ◽  
Guangxue Zheng ◽  
Kashif Iqbal ◽  
...  
Keyword(s):  
Velocity Profile ◽  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Wave Dispersion ◽  
Dispersion Property ◽  
Scholte Wave ◽  
Shear Wave Velocity Profile ◽  
Masw Method ◽  
Low Shear

Recent studies have illustrated that the Multichannel Analysis of Surface Waves (MASW) method is an effective geoacoustic parameter inversion tool. This particular tool employs the dispersion property of broadband Scholte-type surface wave signals, which propagate along the interface between the sea water and seafloor. It is of critical importance to establish the theoretical Scholte wave dispersion curve computation model. In this typical study, the stiffness matrix method is introduced to compute the phase speed of the Scholte wave in a layered ocean environment with an elastic bottom. By computing the phase velocity in environments with a typical complexly varying seabed, it is observed that the coupling phenomenon occurs among Scholte waves corresponding to the fundamental mode and the first higher-order mode for the model with a low shear-velocity layer. Afterwards, few differences are highlighted, which should be taken into consideration while applying the MASW method in the seabed. Finally, based on the ingeniously developed nonlinear Bayesian inversion theory, the seafloor shear wave velocity profile in the southern Yellow Sea of China is inverted by employing multi-order Scholte wave dispersion curves. These inversion results illustrate that the shear wave speed is below 700 m/s in the upper layers of bottom sediments. Due to the alternation of argillaceous layers and sandy layers in the experimental area, there are several low-shear-wave-velocity layers in the inversion profile.

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