Geotechnical Engineering Journal of the SEAGS & AGSSEA

A Study of Stress-Strain Characteristics of Sandstone under Uniaxial Compression Subjected to Wetting-Drying Cycles

Hanhui Wu — 2026-06-24

To study the mechanical characteristics of sandstone subjected to wetting-drying cycles, the paper studies the failure characteristic stress of sandstone subjected to wetting-drying cycles based on a uniaxial compression test, i.e crack intiation stress , dilatancy stress , and peak strength . There is no significant linear correlation between the crack initiation stress and the number of wetting-drying cycles. Based on the law of conservation of energy, the energy characteristics and damage mechanisms of sandstone during failure. The result shows that the total strain energy U, releasable elastic strain energy U^e, and dissipated strain energy U^d absorbed per unit volume of rock are decreasing linearly with the increase in number of wetting-drying cycles. Research finds that shifting from positive volumetric strain to negative volumetric strain (i.e. transforming from compression to dilation) would lead to release of elastic strain energy U^e and drastic rise of dissipated strain energy U^d, and is the turning point from crack propagation to approximate failure. The wetting-drying cycles accelerate the failure of sandstone specimens and reduce the dissipated strain energy U^d required for failure, presenting as a decrease in peak strength and elasticity modulus at the macroscopic level.

Overbreak Reduction by Optimized Drilling and Blasting Parameters: Lessons from the High-Speed Railway Project in Thailand

Kuo Chieh Chao — 2026-06-24

This study investigates practical measures to reduce overbreak in drill-and-blast tunnel excavation using the New Austrian Tunneling Method (NATM). The project data from the Muak Lek tunnel section of the High-Speed Railway Project in Thailand was collected and analyzed in the study. Initial field observations revealed that Class IV rock conditions in the study area exhibited an average overbreak of approximately 30%, which significantly exceeded the allowable limits. A nearby double-track railway tunnel with similar rock conditions recorded lower overbreak values (11.7 – 14.0% across rock classes II – IV). Based on these findings and the authors’ experience, an optimized blasting approach was developed involving reduced drill hole length, lowered powder factor, precise hole alignment, and smooth blasting with small emulsion charges and detonating cord. A field test was conducted to assess the effectiveness of the proposed approach in a selected Class IV rock section. In nearby sections at the test site, the percent overbreak values were 51.6% and 41.1%, while the improved section achieved a reduced overbreak of 9.3% after applying the proposed approach. The results confirm that adjusting drilling and blasting parameters to site and construction conditions can significantly improve excavation control, offering practical measures for similar NATM tunnel projects.

A Systematic Approach of Invention of Wave Resilient Wrap Face Embankment with Electricity Production Capacity

Ripon Hore — 2026-06-24

Climate-resilient infrastructure is the burning question in today’s world. Resilient infrastructure will affect future scenarios for future generations, particularly low-carbon infrastructure that is resilient to future climate impacts (UK Climate Change Risk Assessment 2022). The accelerated pace of meeting ambitious carbon emissions targets includes mitigation and adaptation processes that impact all social and economic aspects. Reducing our dependence on fossil fuels requires the development of reliable technologies to better harness natural energy sources (e.g., solar, wind, geothermal). In particular, hydropower has the potential to significantly reduce carbon emissions and become an environmentally friendly energy source. In this paper, a systematic approach has been taken to build a wave resilient wrap face embankment that can produce electricity, and can be a sustainable, environmentally friendly solution. In most countries, there is a shortage of electricity, and they do not use waves to produce electricity. According to the Center for Policy Dialogue, in the financial year 2022-23, 2.5 million US dollars was allocated for the electricity sector, whereas in the budget for FY2023-24, the allocation for the energy and power sector is 3.2 US dollars in Bangladesh. This indicates the increasing demand for electricity, which can be met by using wave energy. Studies and research from various countries over the past years have been reviewed in this research. The sustainable electricity generation and building secure embankments both are needed and a wave resilient wrap face embankment with the ability to produce electricity is a great solution to this problem.

3-D Bearing Capacity Analysis of Square Foundation in Spatially Variable Cohesive Frictional Soil

Tarek Kormi — 2026-06-24

Natural soil variability is a well-known issue in geotechnical design particularly in footing design. When subsoil must be characterized in terms of mechanical properties, random finite element method (RFEM) can be effectively adopted. This method had been widely considered in two-dimensional case (plane strain condition) focusing on soil strength variability in two dimensions and assuming no variability along the direction perpendicular to the considered plane by default. This limitation can significantly influence probabilistic bearing capacity evaluations and emphasizes the importance of three-dimensional (3-D) analysis in such stochastic characterization. The 3-D analysis in stochastic context has not fully explored as such analysis is time-consuming and different stochastic conditions can be considered. The purpose of this paper is to use RFEM for the bearing capacity assessment of a square shallow foundation to endorse our understanding of the influence of 3-D analysis on bearing capacity and on failure mechanisms. In this study, soil shear strength properties (i.e. soil cohesion and friction angle) are assumed to be independent and correlated random fields. Results show that the influence of correlation between shear strength properties can be significant and lead to more realistic estimates of bearing capacity. A probability distribution of bearing capacity was then estimated and used to calibrate safety factors for reliability purposes.