Nur Azwin Ismail

The Influence of Electrical Resistivity Array on its Soil Electrical Resistivity Value

Electrical resistivity technique has become a popular alternative tool by the geotechnical engineers in subsurface investigation. This study presents the influence of soil electrical resistivity value (ERV) due to the different types of electrical resistivity array used in practice. The dissimilarity of ERV was become a popular debate by the engineers which posses less fundamental knowledge in this area. In the past, the theory of electrical resistivity technique was less being discovered by the engineer which creates lots of black boxes during the utilization of electrical resistivity method (ERM) in engineering purposes. Hence, the result which produced from the ERM was difficult to deliver in a sound of definitive ways due to lack of knowledge and experienced of most engineers. Hence, this study presents the influence of soil ERV due to the different types of array used with particular reference to as Dipole-dipole and Pole-dipole. A line of electrical resistivity imaging was performed on small embankment of sandy and lateritic soil with different types of array using ABEM SAS (4000) equipment. Three in line of soil samples were tested for moisture content (w) test immediately after the electrical resistivity data acquisition was completely measured. Moreover, particle size distribution test also was performed for all soil samples in order to support the findings. It was found that the ERV was never be the same for each types of array used even on the same particular location of the survey line. However, it was found that there was a consistent relationship between ERV and moisture content for both types of soil tested which can be represent by ERV 1/w. Hence, it was found that ERV produced was relative to the types of array used during the field measurement. Each types of array were applicable to be used in subsurface profiling and its selection was subjected to the target of interest.

Slope monitoring by using 2-D resistivity method at Sungai Batu, Pulau Pinang, Malaysia

Slope is a dynamic system of geo-environmental phenomena that related to the movement of the soil and rock masses. In Pulau Pinang, the occurrence of slope related phenomena such as landslide and rock fall has become a huge issue especially during rainy season as the government would have to invest more for the people safety. 2-D resistivity method is one of the geophysical methods that can be applied to overcome this issue thus prepare countermeasure actions. Monitoring is one of the common acquisition technique that has been used in solving such issue. This technique was applied to identify and monitor changes at the suspected area and thus, countermeasure steps can be taken accordingly and not blindfolded. Starting from August until November 2016, a 200 m survey line of 2-D resistivity survey had been conducted monthly at Sungai Batu, Pulau Pinang slope for monitoring purpose. Three resistivity ranges were able to detect within the subsurface. Resistivity value of 250 – 400 Ωm indicated the low resisti...

Determination of slope failure using 2-D resistivity method

Landslides and slope failure may give negative economic effects including the cost to repair structures, loss of property value and medical costs in the event of injury. To avoid landslide, slope failure and disturbance of the ecosystem, good and detailed planning must be done when developing hilly area. Slope failure classification and various factors contributing to the instability using 2-D resistivity survey conducted in Selangor, Malaysia are described. The study on landslide and slope failure was conducted at Site A and Site B, Selangor using 2-D resistivity method. The implications of the anticipated ground conditions as well as the field observation of the actual conditions are discussed. Nine 2-D resistivity survey lines were conducted in Site A and six 2-D resistivity survey lines with 5 m minimum electrode spacing using Pole-dipole array were performed in Site B. The data were processed using Res2Dinv and Surfer10 software to evaluate the subsurface characteristics. 2-D resistivity results from...

Applying 2-D resistivity imaging and ground penetrating radar (GPR) methods to identify infiltration of water in the ground surface

Infiltration of water into the soil mostly happens in area near to the ocean or area where rain occurred frequently. This paper explains about the water infiltration process that occurred vertically and horizontally at the subsurface layer. Infiltration act as an indicator of the soil’s ability to allow water movement into and through the soil profile. This research takes place at Teluk Kumbar, Pulau Pinang, area that located near to the sea. Thus, infiltration process occurs actively. The study area consists of unconsolidated marine clay, sand and gravel deposits. Furthermore, the methods used for this research is 2-D Resistivity Imaging by using Wenner-Schlumberger array with 2.5 m minimum electrode spacing, and the second method is Ground Penetrating Radar (GPR) with antenna frequency of 250MHz. 2-D Resistivity Imaging is used to investigate the subsurface layer of the soil. Other than that, this method can also be used to investigate the water infiltration that happens horizontally. GPR is used to inv...

Identification Of Rippability And Bedrock Depth Using Seismic Refraction

Spatial variability of the bedrock with reference to the ground surface is vital for many applications in geotechnical engineering to decide the type of foundation of a structure. A study was done within the development area of Mutiara Damansara utilising the seismic refraction method using ABEM MK8 24 channel seismograph. The geological features of the subsurface were investigated and velocities, depth to the underlying layers were determined. The seismic velocities were correlated with rippability characteristics and borehole records. Seismic sections generally show a three layer case. The first layer with velocity 400–600 m/s predominantly consists of soil mix with gravel. The second layer with velocity 1600–2000 m/s is suggested to be saturated and weathered area. Both layers forms an overburden and generally rippable. The third layer represents granite bedrock with average depth and velocity 10–30 m and >3000 m/s respectively and it is non‐rippable. Steep slope on the bedrock are probably the results...