Aziman Madun

The monitoring and cementation behavior of electrokinetic stabilisation technique on batu pahat marine clay

This paper outlines the monitoring and soil fabric results from an experimental study of electrokinetic stabilisation (EKS) technique. The monitoring results were important in assessing the efficiency of the technique towards Batu Pahat marine clay. Two reactors were set up; 1.0 M of calcium chloride (CaCl2) and sodium silicate (Na2SiO3) as the electrolyte and stainless steel plates as the electrodes. EKS technique was continued for 21 days with a constant voltage gradient (50 V/m). This technique was performed in two phases where the alteration of EKS was the combination of stabilizers used. The combinations of stabilizers in phase 1 and 2 were CaCl2 - distilled water (DW) and CaCl2 - Na2SiO3, respectively. The technique was monitored using electric current, total inflow and outflow of electrolytes and pH of electrolytes. It showed fluctuated profiles of electric current for both phases, attributed by the introduction of calcium ions from the anode compartment. The inflow and outflow of electrolytes results showed that electromigration and electroosmosis occurred during EKS and it indicated the movement of anion and cation to the opposite direction. The pH of electrolytes kept constant value and balanced by electrolysis process at the cathode. Image of soil fabric for untreated and treated clay were presented where most images shows a flaky particles. The observation of those images indirectly explained the effect of cementation behavior of treated clay.

Groundwater Seepage Mapping using Electrical Resistivity Imaging

In recent years, electrical resistivity method (ERM) has widely being applied as an alternative tool in engineering, environmental and archeological studies. A global image of groundwater seepage problem was difficult to obtained using conventional geotechnical method due to the efficiency of cost, time and result coverage. This study was conducted using electrical resistivity survey in order to investigate the potential of the problematic zone due to the groundwater seepage problem. ABEM SAS 4000 equipment set was used in during the resistivity data acquisition stage. Six (6) resistivity spread lines (SP) were performed across the slopes area using 2-D electrical resistivity imaging. The raw data was processed using RES2DINV and SURFER software for 2-D and 3-D subsurface image. Interpretation of electrical resistivity results was verified using the existing borehole and geochemistry results. Geochemistry results analyses were used Atomic Absorption Spectrometer (AAS) for determining cation and Ion Chromatography (IC) is for anions. Anion elements were studied consists of chloride, bicarbonate, nitrate and sulfate while cation elements consists of sodium, potassium, calcium and magnesium. All the elements were analyzed by using Piper Diagram to determine geochemistry facies in the groundwater. It was found that low resistivity value (ERV) which associated to groundwater (10 ~ 100 Ωm) can be found starts from the ground surface (0 m) to a greater (> 10 m) depth of the subsurface profile. The finding of the study water seepage can be categorized as Ca-HCO that indicator a typical of shallow fresh groundwater. The finding of the study is important to determine source process of water seepage on that area. This study has successfully demonstrates that the application of ERM with supporting borehole and geochemistry data was able to provide a comprehensive results due to the groundwater leakage detection.

Leachate Characteristics of Contaminated Soil Containing Lead by Stabilisation/Solidification Technique.

Contaminated soil is often a problem and typical concern in the developing countries due to the lack of clean soil for development, such as in Malaysia. The objective of this study is to investigate the performance of the available techniques for soil remediation contaminated with lead (Pb) through Stabilisation/Solidification (S/S) technique. In this study, cockle shell powders at different percentages (2.5%, 5% and 7.5%) were added as a partial replacement of cement. Toxicity Characteristics Leaching Procedure (TCLP) was conducted to determine the effectiveness of the S/S technique to treat the contaminated soil. The results showed a 99% reduction of Pb concentration after the contaminated clay soil was treated with S/S technique. The combination of cement and cockle shell powders is very effectively used in the remediation of lead contaminated soil and reducing the amount of cement usage for sustainability approaches.

The Soil-Water Characteristic Curve of Unsaturated Tropical Residual Soil

This study was conducted to determine the SWCC of unsaturated tropical residual soil in Kuala Lumpur, Malaysia. Undisturbed soil samples at five locations of high-risk slopes area were taken at a depth of 0.5 m using block sampler. In the determination of the SWCC, the pressure plate extractor with the capacity of 1500 kN/m2 has been used. The index properties of the soil such as natural moisture content, Atterberg limits, specific gravity, and soil classification are performed according to BS 1377: Part 2: 1990. The results of index properties show that the natural moisture content of the soil is between 36% to 46%, the plasticity index is between 10% - 26%, the specific gravity is between 2.51 - 2.61 and the soils is classified as silty organic clay of low plasticity. The SWCC data from the pressure plate extractor have been fitted with the Fredlund and Xing equation. The results show that the air entry value and residual matric suction for residual soils are in the range of 17 kN/m2 to 24 kN/m2 and 145 kN/m2 to 225 kN/m2 respectively. From the fitting curve, it is found that the average value of the Fredlund and Xing parameters such as a, n and m are in the range of 0.24-0.299, 1.7-4.8 and 0.142-0.440 respectively.

Comparison of Geotechnical Properties of Laterite, Kaolin and Peat

This paper compares some geotechnical properties of Kaolin, Laterite and Peat. Laterite was collected from Bukit Banang while Peat sample was collected from Parit Nipah, both locations were in Batu Pahat, Johor. Meanwhile, kaolin that was used in this research was manufactured kaolin. These soil samples were subjected to routine laboratory analysis and resulting data were analyzed statistically using a correlation analysis. A laboratory testing program consists of “Basic properties test” to obtain general information on the materials (e.g Natural moisture content, Atterberg Limit, Specific gravity, grain size analysis, chemical composition and pH) and “Geotechnical properties tests” to measure specific properties that characterize soil behaviour for design and constructability assessments (e.g Standard Proctor Test, Unconfined Compressive Strength and CBR).The results showed that the Natural/initial moisture content for laterite, peat and kaolin is 22.54%, 480.61% and 0.22% respectively. Meanwhile Specific gravity for each soil was in the range 1.50-2.79.It was also found that the pH of all soil is acidic which lay in the range of 3.76-5.95.The UCS for the optimally compacted sample of laterite is 445.77 kPa, kaolin is 199.23 kPa and for peat is 58.70 kPa. This paper summarizes the result of analysis performed on all tests conducted. Based on the results, the geotechnical property of the soil is a highly dependent with the type of soil and therefore, determining the soil characterization and the soil strength should be considered during the planning phase of any earthwork construction operation.

Vulnerability assessment of existing low-rise reinforced concrete school buildings in low seismic region using ambient noise method

Ground movements triggered by the Bukit Tinggi earthquakes in 2007 to 2009 are believed to be the possible cause of several structural damages on a secondary school building of SMK Bukit Tinggi, in the state of Pahang, Malaysia. This paper describes the ambient noise study conducted on the damaged building (a 4-storey reinforced concrete frame laboratory building) and the adjacent buildings using tri-axial 1 Hz seismometer sensors. Fourier amplitude spectra (FAS) analysis was applied to determine the buildings natural frequencies for vulnerability assessment of the damaged structure in both longitudinal and transverse axes. Significant multiple peaks of FAS curves used for natural frequencies determination of the buildings show values between 4.18 to 4.34 Hz, 5.04 to 5.23 Hz, 6.07 to 6.54 Hz and 8.17 to 8.81 Hz, indicating the existence of translational and torsional vibration modes acting on the buildings. Differences in dynamic behaviour between the laboratory and the adjacent buildings may be responsible for the structural damages due to the independent structural response and excessive torsional effect during the Bukit Tinggi earthquake tremors.

Barren Acidic Soil Assessment using Seismic Refraction Survey

Seismic refraction method is one of the geophysics subsurface exploration techniques used to determine subsurface profile characteristics. From past experience, seismic refraction method is commonly used to detect soil layers, overburden, bedrock, etc. However, the application of this method on barren geomaterials remains limited due to several reasons. Hence, this study was performed to evaluate the subsurface profile characteristics of barren acidic soil located in Ayer Hitam, Batu Pahat, Johor using seismic refraction survey. The seismic refraction survey was conducted using ABEM Terraloc MK 8 (seismograph), a sledge hammer weighing 7 kg (source) and 24 units of 10 Hz geophones (receiver). Seismic data processing was performed using OPTIM software which consists of SeisOpt@picker (picking the first arrival and seismic configureuration data input) and SeisOpt@2D (generating 2D image of barren acidic soil based on seismic velocity (primary velocity, Vp) distribution). It was found that the barren acidic soil profile consists of three layers representing residual soil (Vp= 200-400 m/s) at 0-2 m, highly to completely weathered soil (Vp= 500-1800 m/s) at 3-8 m and shale (Vp= 2100-6200 m/s) at 9-20 m depth. Furthermore, result verification was successfully done through the correlation of seismic refraction data based on physical mapping and the geological map of the study area. Finally, it was found that the seismic refraction survey was applicable for subsurface profiling of barren acidic soil as it was very efficient in terms of time, cost, large data coverage and sustainable.

Seismic Surface Wave Testing for Investigating the Shallow Soil Profile

This research explores the use of the seismic surface wave technique which is called as a spectral analysis of surface wave (SASW) for investigating the shallow soil profile. The testing was conducted on soft ground located at Universiti Tun Hussein Onn Malaysia (UTHM). The testing was conducted using a new developed in-house seismic surface wave testing system. An impact source using 5 kg hammer is used to generate seismic energy and four differencesarrangement of the source to receiver distances to produce soil profile. The profile of phase velocity was obtained at a depth of 0.15 m to 1.8 m were between 68 m/s and 95 m/s. The results were calibrated with the hand vane shear test which is used to obtain the undrained shear strength and thus converted empirically to seismic velocity at 45 m/s and 95 m/s. The result shows good agreement between velocity obtained from the surface wave testing system and hand vane shear test. Therefore, the new developed in-house seismic surface wave system has been proven can be used to determine the seismic velocity at shallow depth.

Monitoring of Electric Current During Electrokinetic Stabilisation Test for Soft Clay using EKG Electrode

Electrokinetic Stabilisation (EKS) method has the potential to overcome problems on highly compressible clay. This study presents the monitoring results from an experimental study of EKS on soft clay soil. Inactive kaolinite clay, inert electrode and distilled water (DW) were used as a pure system mechanism before any chemical stabilisers are utilised for stabilisation. Therefore, this monitoring data will provide a baseline study to improve efficiency of the EKS approach for ground improvement application. An inert electrode of Electrokinetic Geosythentic (EKG) developed at the Newcastle University was utilised to apply a constant voltage gradient of 50 V/m across a soil sample of 400 mm length. The distilled waters were used at the pore electrolyte fluid compartments and supplied under zero hydraulic gradient conditions for periods of 3, 7 and 14 days. Throughout, monitoring data of electric current for all treatments were measured. Results showed that the electric current trend in this pure system was attributed to the electrochemical effects in the clay-water electrolyte system.

Robust Weighted-mean Approach for the Evaluation of Ground Improvement Columns Using Surface Wave Analysis

This paper demonstrates the application of surface wave analysis specifically for the evaluation of ground improvement columns, and considers the susceptibility of phase measurements to noise associated with this technique. This is addressed by introducing a robust approach of calculating the phase velocity based upon a weighted-mean approach that uses the signal-to-noise ratio (SNR) of the signal as a variable cost function to obtain an optimal phase velocity estimation. Experimental data was collected from a laboratory scale setup of a 0.1 m diameter x 0.15 m depth gravelly-sand column installed within a 0.6 m x 0.3 m x 0.3 m block of homogenous kaolinite-clay. Results from the measurements indicated Rayleigh-wave phase velocities of 59 m/s and 110 m/s for the clay and column respectively. The weighted-mean approach demonstrated consistently more accurate phase estimation as compared to the case of a rigid threshold approach.