Quantifying Desiccation Cracks for Expansive Soil Using Machine Learning Technique in Image Processing

The formation of desiccation cracks has detrimental effects on the hydraulic conductivity that affects the overall mechanical strength of expansive soil. Qualitative analysis on the desiccation cracking behaviour of expansive soil provided understanding of the subject based on various concepts and theories, while quantitative analysis aided these studies through numerical supports. In this study, a machine learning technique in image processing is developed to evaluate the surface crack ratio of expansive soil. The desiccation cracking tests were conducted on highly plastic kaolinite slurry samples with plasticity index of 29.1%. Slurry-saturated specimens with thickness of 10 mm were prepared. The specimens were subjected to cyclic drying-wetting conditions. The images are acquired through a digital camera (12 MP) at constant distance to monitor the desiccation cracks. The images are then pre-processed using OpenCV before crack feature extraction. In this study, a total of 54 desiccation crack images were processed, along with 8 images from trial test to train the model. The processed images are used to quantify the desiccation cracks by evaluating surface crack ratio and average crack width. It was identified that the accuracy of the model for the quantification of surface crack ratio and average crack width were 97.24% and 93.85% respectively with average processing time of 1.51s per image. The results show that the model was able to achieve high accuracy with sufficient efficiency in determining important parameters used for crack characterization

Liquefaction resistance of sand matrix soils

Numerous researches have been focusing on the roles of fines in liquefaction resistance of sand matrix soils (sand dominant soil that contains little presenting fines). It has been reported that the presence of plastic fines would either imposed additional liquefaction resistance of sand matrix soils or caused reduction to the liquefaction resistance. This paper aims to present the liquefaction resistance of sand matrix soils with respect to different fines content based on the results from cyclic tests using triaxial testing system. The sand matrix soils were reconstituted by mixing the plastic fines (kaolin and bentonite) to the clean sand at seven different percentages by weight. Results showed that liquefaction resistance of sand matrix soils decreases with an increase of fines content until a minimal value and increases thereafter. It was identified that the presence of fine contents to give the minimum liquefaction resistance were 20 % for sand-bentonite mixtures and 25 % for sand-kaolin mixtures. These values represent the threshold fines content for respective mixtures

Static response on lime column and geotextile encapsulated lime column (GELC) stabilised marine clay under vertical load

Marine clay, which is widely encountered in coastal area in Malaysia, is a problematic base material. Previous researchers reported that deep lime stabilisation can significantly improve clay. However, insufficient confining pressure from surrounding soil normally lead to the inferior performance on the upper part of column such as column head crushing and larger deformation on the surrounding soil at top part of column. Therefore, geotextile encapsulation was proposed for lime column in this study. Static response and stress distribution are essential in the understanding on behaviour of columnar stabilised soil under vertical load. Multi stages loading tests were conducted on Pontian marine clay, with and without geotextile encapsulation. Stress concentration ratio (smid/ ssoil) was examined in each loading stage, where it is defined as stress on column (smid) divided by stress on surrounding soil (ssoil). The samples were cured for 14, 28 and 56 days before tested. It was found that stress concentration ratio was dependent on column materials strength properties and applied loading. Geotextile encapsulation increased the stress concentration ratio on lime column. Stress concentration increment effect by geotextile encapsulation was further enhanced by the confining pressure of surrounding soil; however, the effect reduced with increase of applied loading. Higher stress concentration ratio indicated lesser load on surrounding soil and therefore the soil settlement could be reduced

Soil improvement by reinforced stone columns based on experiments works

Methods for analysis of stability and deformation under static and dynamic loading are exported. Stone columns are installed using a process similar to vibro-compaction, except that a gravel backfill is used, and they are typically installed in slightly cohesive soils or silt rather than clean cohesion less soils. In the dry soils, a cylindrical cavity is formed by the vibrator that is filled from the bottom up with gravel/crushed rock. The purpose of this research paper is to provide a review on ground improvement for using reinforced stone columns in geotechnical engineering projects. There is special focus on how to performance and evaluate ground improvement using reinforced stone column for special purposes. The previous results indicated the reinforced stone columns significantly increase the bearing capacity and tension of the soil. Based on previous results, critical values were discussed and recommended

Soil improvement by reinforced stone columns based on experimental work

Methods for analysis of stability and deformation under static and dynamic loading are exported. Stone columns are installed using a process similar to vibro-compaction, except that a gravel backfill is used, and they are typically installed in slightly cohesive soils or silt rather than clean cohesion less soils. In the dry soils, a cylindrical cavity is formed by the vibrator that is filled from the bottom up with gravel/crushed rock. The purpose of this research paper is to provide a review on ground improvement for using reinforced stone columns in geotechnical engineering projects. There is special focus on how to performance and evaluate ground improvement using reinforced stone column for special purposes. The previous results indicated the reinforced stone columns significantly increase the bearing capacity and tension of the soil. Based on previous results, critical values were discussed and recommended

Virtual design and construction (VDC) for double-storey residential building – Case study

Virtual design and construction (VDC) is a combination of building information modelling (BIM) technologies with adequate work and management scheme for product in supporting people working together in an integrated and simultaneous way. The use of VDC in construction project has positive effects in reducing risk related to design and multidisciplinary coordination. This enhanced the decision-making process by reducing miscommunication issue. This paper presents a case study to investigate the process of integrating different dimensions of information i.e., time (4D) and cost (5D) with a 3D model for doublestorey residential building construction considering the zoning conditions. Implementation of VDC with zoning plan leads to an efficient construction management in project feasibility study. It enabled comparison of a virtual model to evaluate the advantages and practicality of VDC for doublestorey residential building. The 3D architectural and structural models elements are prepared at level of detail (LOD300) using Autodesk Revit. The 3D models are then integrated to simulation software (i.e., Autodesk Navisworks Manage). Visualisation of the project (i.e., 4D and 5D) is achieved as the outcome of the simulation by implementation of VDC. The results revealed that the practicability of VDC was affected by LOD and software interoperability

Anisotropically Consolidated Undrained Compression Test on Residual Soil

In Malaysia, the shear strength and corresponding deformation characteristics of residual soils are normally investigated by isotropically consolidated undrained (CIU) triaxial test. In the present study, anisotropically consolidated undrained compression (CAU) tests were carried out and explored in an attempt to facilitate understanding on the fundamental behaviours of a selected residual soil. A triaxial apparatus setup which was capable of performing the CAU test was first developed. Through a monotonic strain-controlled triaxial test apparatus, soil properties and stress paths could be obtained experimentally. It was confirmed that the newly fabricated triaxial apparatus could provide reasonable experimental results. As distinguished from the isotropically consolidated undrained compression (CIU) test, anisotropic stresses were induced in the stress path test. It follows that the soil responses were different between the CIU and CAU tests. The coefficient of earth pressure at rest (Ko) values as obtained in the present experiment showed a good agreement with the values estimated using equation reported by Jaky (1948)

Anisotropically Consolidated Undrained Compression Test on Residual Soil

In Malaysia, the shear strength and corresponding deformation characteristics of residual soils are normally investigated by isotropically consolidated undrained (CIU) triaxial test. In the present study, anisotropically consolidated undrained compression (CAU) tests were carried out and explored in an attempt to facilitate understanding on the fundamental behaviours of a selected residual soil. A triaxial apparatus setup which was capable of performing the CAU test was first developed. Through a monotonic strain-controlled triaxial test apparatus, soil properties and stress paths could be obtained experimentally. It was confirmed that the newly fabricated triaxial apparatus could provide reasonable experimental results. As distinguished from the isotropically consolidated undrained compression (CIU) test, anisotropic stresses were induced in the stress path test. It follows that the soil responses were different between the CIU and CAU tests. The coefficient of earth pressure at rest (Ko) values as obtained in the present experiment showed a good agreement with the values estimated using equation reported by Jaky (1948)

Geotextile Encapsulation as Protection to Lime Column under Shear Load

Deep lime stabilization such as lime column, can effectively improve the problematic soft clay through stabilization, settlement reduction and embankment stabilization. Nevertheless, the reduction of lime column load capacity was often encountered due to the column lateral displacement which was induced by high lateral earth pressure in embankments and deep excavation. In order to protect and enhance the mobilization of lime column strength, geotextile encapsulation was proposed for lime column. In this study, large shear box tests were conducted on lime column and geotextile encapsulated lime column (GELC) stabilized Pontian marine clay samples with different column sizes and curing ages, in order to investigate the performance of geotextile encapsulation on lime column in Pontian marine clay under shear loading. It was found that geotextile encapsulation effectively increased the horizontal shear resistance of lime column and protected the column from defect due to lateral displacement, especially at early age when modification was still in process. Geotextile encapsulation also successfully protected lime column from shear and bending failure under lateral load