Seismic evaluation of vibro-stone column

Ground improvement work is crucial in enhancing the characteristics of weak soils commonly encountered in Civil Engineering, and one such technique commonly used is vibro-stone columns. An assessment of the effectiveness of such an approach is critical to determine whether the quality of the works meets the prescribed requirements. Conventional quality testing suffers limitations including: limited coverage (both area and depth) and problems with sampling quality. Traditionally quality assurance measurements use laboratory and in-situ invasive and destructive tests. However geophysical approaches, which are typically non-invasive and non-destructive, offer a method by which improvement profiles can be measured in a cost effective way. Of these seismic surface waves have proved the most useful to assess vibro-stone columns, however, to date much of the previous work conducted has focussed on field based observations making detailed evaluation of this approach difficult. This study evaluates the application of surface waves in characterizing the properties of laterally heterogeneous soil, specifically for using in the quality control of vibro-stone column. Three models were employed which began with a simple model and extended finally to complex model: (1) concrete mortar was used to establish the method, equipment and its system, (2) pilot test on a small scale soft kaolin to adopt a model vibro-stone column and (3) main test contained a configuration of vibro-stone column in soft Oxford clay. A generic scaled-down model of vibro-stone column(s) was constructed. Measurements were conducted using different arrays of column configuration, using sand to simulate stone material. This idealized set of laboratory conditions were used to provide guidelines for the interpretation of field measurements. The phase velocity obtained from the controlled tests showed close agreement to those reported in literature and with those generated through empirical correlations with vane shear test. The dispersive curve demonstrated an increased phase velocity with increasing wavelength for the measurements on the clay (between columns), and decreased phase velocity with increasing wavelength for the measurements on the column. More interestingly, the results showed that in the characterization of lateral non-homogeneities, the phase velocity versus wavelength relationship varies on stone columns of different diameters and densities. This illustrated that the shear modulus profiles are influenced by the effective region that spans both the lateral and depth axes, and also demonstrated how the results can be influenced by the positioning of sensors with respect to the survey target. This research demonstrates how Rayleigh waves can be used for quality assurance when constructing vibro-stone columns

Laboratory Scale Seismic Surface Wave Testing for the Determination of Soil Elastic Profiles

Seismic surface wave testing is well-adapted to the study of elastic parameters and, hence, the elastic profile of soils in the field.  Knowledge of a ground’s stiffness profile enables the prediction of ground movement and, thus, the quality of the foundation.  The stiffness parameter obtained in this research corresponds to the measurement of the seismic surface wave phase velocity of materials, which relates to the very small strain shear modulus.  This paper describes a methodology for performing surface wave testing in the laboratory.  In comparison with field tests, a laboratory-scale experiment offers the advantage of allowing the process of data collection to be calibrated, and analytical studies can be carried out as the properties of the material under test are controllable and known a priori.  In addition, a laboratory scale experiment offers insight into the interaction between the seismic surface wave, the soil, the boundary and, hence, the constraints associated with the seismic surface wave technique.  Two simplified models of different sizes were developed using homogeneous remoulded Oxford Clay (from Midlands region of the UK).  The laboratory experimental methodology demonstrated that the seismic surface wave equipment used in the laboratory was directly influenced by the clay properties as well as the size of the test model.  The methodology also showed that the arrangement of the seismic source and the receivers had an impact on the range of reliable frequencies and wavelengths obtained.&nbsp

Stability Analysis of Weathered Rock Cut Slope Using Geological Mapping and Laboratory Tests

A study on determining the stability of weathered rock cut slope using geological mapping and laboratory tests. The study is divided into two parts: field work and laboratory testing. The field study focused on the measurement and analysis of the orientation and characteristics of discontinuity. Identification of rock types, weathering grades and observation of cut slope conditions were also included in the field study. Laboratory testing involved determination of natural moisture content, particle size distribution and shear strength. Discontinuity data were analyzed using stereographical method for identification of potential instabilities. A factor of safety (FOS) analysis was conducted on unstable cut slopes using SWEDGE software and manual calculation It is found that the geological mapping and laboratory tests are feasible for assessing slope stability. The FOS analysis has distinguished 10 slope to be considered as fail whilst the other 6 are consider stable same as field observation

The Effect of Compaction Towards Resistivity Value

Electrical resistivity tomography is a non-destructive method of site investigation that involves injecting electricity into the sample and measuring subsurface resistance. This study looked at the effects of compaction on soil as well as the relationship between different degrees of compaction of soil and resistivity value. The soil used in this experiment was lateritic soil. The sample was compacted in a standard proctor mould with a diameter of 10.20cm and 11.6 cm height. The soil’s resistivity was measured after the soil was compacted inside the mould. The resistivity testing was conducted using soil resistivity meter model Miller 400A. ASTM G57 was used for electrical resistivity testing. This research emphasizes the impact of compaction on resistivity value, as soil reduces resistivity value when the soil has higher moisture content which is 120 Ωm at 37%, and 190 Ωm at 25%. By comparing the results of different moisture content of soil samples under varied degrees of compaction, better resistivity interpretation tables may be generated

Artificial Neural Network in Seismic Reflection Method for Measuring Asphalt Pavement Thickness

A non‐destructive measurement of asphalt pavement layer thickness using seismic reflection was adopted together with coring test at similar site for comparison. The test was carried out on pavements around university campus’s road to measure the asphalt pavement layer thickness. The on-site seismic reflection testing was carried out using three piezoelectric sensors to capture time travel of wave motion, a light ball bearing to produce a high frequency seismic wave source and a data logger for data acquisition. The data processing is conducted in the time domain exclusively using a feedforward artificial neural network (ANN) using MATLAB software. A graphical interface is developed for viewing and extracting the result to make the processing of the seismic data feasible and user-friendly. The seismic reflection method analysis using the ANN successfully measured the asphalt pavement layer thickness. This study of the reflection method for measuring the pavement thickness compared with coring indicates the average accuracy of five testing sites was 93%. It shows that the seismic reflection able to demonstrate the capability to measure thickness of pavement in non-destructive way at a reliable accuracy

Correlation of Electrical Resistivity Tomography and Geotechnical Field Data for Soil Profile Characterization

This study looked at the effects of compaction on resistivity values as well as the relationship between different degrees of compaction. The material used in this experiment was laterite soil. The sample was tested into a standard proctor mould. The model has 10.20cm diameter and 11.6 cm for height of the mould. Each sample's resistivity was measured entirely compacted.The resistivity testing in this study were conducted using the Miller 400A. ASTM D 422 Standards were used, and for electrical resistivity testing, ASTM G57 is used. This research emphasises the impact of moisture content on resistivity value, as soil reduces resistivity value when the soil has higher moisture content which is 120 Ωm at 37%, and 190 Ωm at 25%. By comparing the results of different moisture content of soil samples under varied degrees of compaction, better resistivity interpretation tables may be generated

A Comparative Analysis of Mechanical Properties Between Granite and Basalt Rock Core Samples

Structural failure occurs when a load-bearing component of a structure fails to support and transfer loads to another element, leading to a breakdown in the performance of the materials in that structural component. The potential for structural failure is influenced by various variables, emphasizing the importance of understanding the behavior and parameters specific to rocks and soils in construction. In order to prevent failures in construction, engineers must possess a fundamental geological knowledge of rocks during the design process, recognizing the limitations of this construction material. Consequently, it is imperative to conduct tests to determine the precise strength of the rock being utilized. This study focused on granite and basalt, employing the Portable Ultrasonic Non-Destructive Digital Indicating (PUNDIT) test, Uniaxial Compressive Strength (UCS) test, and Brazilian test. The selected rock samples adhered to a diameter and thickness ratio of 1:2 or 2:1, depending on the specific test to be conducted. Density, compressive strength, and tensile strength of the rock samples were evaluated following the guidelines provided by the American Society for Testing and Materials (ASTM). The findings revealed that basalt exhibited higher density, compressive strength, and tensile strength compared to granite, with variations in results ranging from 13% to 40%

The influences of basic physical properties of clayey silt and silty sand on its laboratory electrical resistivity value in loose and dense conditions

Non-destructive test which refers to electrical resistivity method is recently popular in engineering, environmental, archaeological and mining studies. Based on the previous studies, the results on electrical resistivity interpretation were often debated due to lack of clarification and evidences in quantitative perspective. Traditionally, most of the previous result interpretations were depending on qualitative point of view which is risky to produce unreliable outcomes. In order to minimise those problems, this study has performed a laboratory experiment on soil box electrical resistivity test which was supported by an additional basic physical properties of soil test like particle size distribution test (d), moisture content test (w), density test (ρbulk) and Atterberg limit test (LL, PL and PI). The test was performed to establish a series of electrical resistivity value (ERV) with different quantity of water content for clayey silt and silty sand in loose and dense condition. Apparently, the soil resistivity value was different under loose (L) and dense (C) conditions with moisture content and density variations (silty SAND = ERVLoose: 600 - 7300 Ωm & ERVDense: 490 - 7900 Ωm while Clayey SILT = ERVLoose: 13 - 7700 Ωm & ERVDense: 14 - 8400 Ωm) due to several factors. Moreover, correlation of moisture content (w) and density (ρbulk) due to the ERV was established as follows; Silty SAND: w(L) = 638.8ρ-0.418, w(D) = 1397.1ρ-0.574, ρBulk(L) = 2.6188e-6E-05ρ, ρBulk(D) = 4.099ρ-0.07 while Clayey SILT: w(L) = 109.98ρ-0.268, w(D) = 121.88ρ-0.363, ρBulk(L) = -0.111ln(ρ) + 1.7605, ρBulk(D) = 2.5991ρ-0.037 with determination coefficients, R2 that varied from 0.5643 – 0.8927. This study was successfully demonstrated that the consistency of ERV was greatly influenced by the variation of soil basic physical properties (d, w, ρBulk, LL, PL and PI). Finally, the reliability of the ERV result interpretation can be enhanced due to its ability to produce a meaningful outcome based on supported data from basic geotechnical properties

Geological Terrain Mapping using Geographic Information System (GIS) and Drone Photogrammetry

The research area was conducted within the Bukit Persekutuan, Kuala Lumpur, and it was located at the latitude 3° 8'32.93"N and longitude 101°40'32.80"E. The researcher carried out geological terrain mapping to evaluate the research area in accordance with the geological terrain classification attributes of each thematic map produced, namely, Terrain map, slope gradient map, erosion, and instability map, as well as construction suitability map. The occurrence of landslide events within the research area becomes a major contributing factor to thoroughly conducting an investigation by field mapping and analysing using the Geographic Information System (GIS) technology. The application of Geographic Information System (GIS) and drone photogrammetry images play an essential role to analyze and processing the data, thus, generate the thematic maps. The research area indicates that about 79.11% of the overall area was not appreciable with erosion, 8.58% contribute to the erosion, 11.00% of recent general instability and 2.97% represent a landslide event. The suitability for development mapping illustrated Class I (23.40), Class II (36.37%), Class III (26.39%), and Class IV (15.50%) where it can be referred to the construction suitability classification system, the suitability for development was high in class I, moderate in class II, low in class III and not suitable in class IV

Marine Clay Soil Treated with Demolished Tile Waste: A Systematic Literature Review

This systematic literature review investigates the stabilization of marine clay soil using demolished tile waste. The study adopts the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) method to comprehensively analyze existing research in this area.The utilization of waste materials for soil stabilization has gained significant attention due to environmental concerns and sustainability objectives. In this review, we explore the effectiveness of using demolished tile waste as a stabilizer for marine clay soil. The analysis reveals that different types of waste materials exhibit varying degrees of improvement in the soil's properties. The results demonstrate a consistent increase in shear strength after stabilization, indicating the suitability of demolished tile waste as a stabilizing agent for soft clay soils. Interestingly, the highest strength is not obtained at the largest additive quantities. Instead, most research papers report a peak in strength at specific additive proportions and curing time, followed by a decline. This phenomenon occurs when the hydration process is complete, and large lumps form between the clay particles. Furthermore, the size of the additive also plays a crucial role in enhancing the strength of problematic soils. Optimal additive size leads to better distribution and interaction with the clay particles, contributing to improved stabilization results. This review provides valuable insights into the potential of utilizing demolished tile waste for enhancing the engineering properties of marine clay soil. The findings highlight the importance of carefully selecting the type and quantity of additives to achieve the desired stabilization outcomes