A common physical technique assessed for improving expansive clays is by the addition of natural fibres to the soil. A good understanding of the impact of stabilisation using fibres on the clay soil's constituents, microfabric, and pore structure is, however, required. Mixtures of clay and fibre, regardless of type or extent, can never change the natural composition of the clay. Even the smallest part must still consist of spaces with clay with the original physical properties and mineralogy. This suggests that, although the mixture may show beneficial physical changes over the initial clay soil, its spatial attributes in terms of mineralogical characteristics, remain unchanged. This paper discusses some of the fundamentals that are not always adequately considered or addressed in expansive clay research, aiming to improve the focus of current and future research investigations. These include the process, mechanics, and implications of chemical and physical soil treatment as well as the concept of moisture equilibration.

Sodium hydroxide (NaOH)-sodium silicate-GGBS (ground granulated blast furnace slag) effectively stabilises sulfate-bearing soils by controlling swelling and enhancing strength. However, its dynamic behaviour under cyclic loading remains poorly understood. This study employed GGBS activated by sodium silicate and sodium hydroxide to stabilise sulfate-bearing soils. The dynamic mechanical properties, mineralogy, and microstructure were investigated. The results showed that the permanent strain (epsilon(p)) of sodium hydroxide-sodium silicate-GGBS-stabilised soil, with a ratio of sodium silicate to GGBS ranging from 1:9 to 3:7 after soaking (0.74%-1.3%), was lower than that of soil stabilised with cement after soaking (2.06%). The resilient modulus (E-d) and energy dissipation (W) of sodium hydroxide-sodium silicate-GGBS-stabilised soil did not change as the ratio of sodium silicate to GGBS increased. Compared to cement (E-d = 2.58 MPa, W = 19.96 kJ/m(3)), sulfate-bearing soil stabilised with sodium hydroxide-sodium silicate-GGBS exhibited better E-d (4.84 MPa) and lower W (15.93 kJ/m(3)) at a ratio of sodium silicate to GGBS of 2:8. Ettringite was absent in sodium hydroxide-sodium silicate-GGBS-stabilised soils but dominated pore spaces in cement-stabilised soil after soaking. Microscopic defects caused by soil swelling were observed through microscopic analysis, which had a significant negative impact on the dynamic mechanical properties of sulfate-bearing soils. This affected the application of sulfate-bearing soil in geotechnical engineering.

The objective of the present study is to evaluate the performance of a levee when subjected to flooding and subsequent seepage through centrifuge model tests. For this, six centrifuge model tests were conducted on a 240 mm high levee model at 30g in a 4.5 m radius large beam geotechnical centrifuge available at the Indian Institute of Technology Bombay, India. A custom-developed flooding simulator is employed to induce identical flood rates on the upstream side of the levee models. Further, using (a) geocomposite (GC) and (b) sand-sandwiched geocomposite (SSGC) as internal chimney drain, the suitability of GC material for dissipation of pore-water pressure (PWP) is also studied. The results of the centrifuge tests are presented and discussed in terms of the development of upstream flood function, subsequent PWP development within the levee body, and the surface settlements observed at the levee's crest. Further, the influence of an internal chimney drain, the material used for its construction, and its type and composition on the seepage response of the levee is discussed in detail. The performance GC chimney drain placed within the levee subjected to flooding-induced seepage is compared with a conventional sand chimney drain. It is observed that a GC-based chimney drain with sand cushioning on both sides in the horizontal portion of the chimney drain performs well. Further, digital image analysis of SEM micrographs of exhumed GC after centrifuge tests and the analyzed PWP data during sustained flooding-induced seepage is found to corroborate well.

Shredded rubber from waste tyres has progressively been adopted in civil engineering due to its mechanical properties, transforming it from a troublesome waste into a valuable and low-cost resource within an eco-sustainable and circular economy. Granular soils mixed with shredded rubber can be used for lightweight backfills, liquefaction mitigation, and geotechnical dynamic isolation. Most studies have focused on sand-rubber mixtures. In contrast, few studies have been conducted on gravel-rubber mixtures (GRMs), primarily involving poorly-graded gravel. Poorly-graded gravel necessitates selecting grains of specific sizes; therefore, from a practical standpoint, it is of significant interest to examine the behaviour of well-graded gravel and shredded rubber mixtures (wgGRMs). This paper deals with wgGRMs. The results of drained triaxial compression tests on wgGRMs are analysed and compared with those on GRMs. Stress-strain paths toward the critical state and energy absorption properties are evaluated. The tested wgGRMs exhibit good shear strength and remarkable energy absorption properties; thus, they can be effectively utilised in several geotechnical applications.

Land degradation threatens environmental and agricultural development in the 21st century. To alleviate this problem, bench terracing has been implemented in eastern and southern Ethiopia. This paper investigates how farmers perceive the attributes and effectiveness of bench terracing in Ethiopia. A Multi-stage sampling techniques were applied to select 384 sample households. For this study, data were collected through primary and secondary sources, and the collected data were analyzed using descriptive statistics and content analysis methods. Primary data were collected using semi-structured questionnaires, focus groups, and key informant interviews; secondary data came from local authority reports. We found that bench terraces restored damaged land and improved crop yield where they were aptly implemented and maintained. The findings also disclose that 57.3% of farmers perceived that bench terracing was more cost-effective; 60.7% responded that it is compatible with the socio-cultural context; and 59.8% perceived Its outcomes are observable to others. However, when a farmer lacks sufficient social, human, or financial capital holdings and capabilities, it often fails. We conclude that the technology was adopted through a multifaceted process, promoted or hindered by both its attributes and effectiveness. Policy-makers and Planners should center those restraints on designing, implementing, and maintaining bench terracing. [GRAPHICS]

The present work attempts to investigate the applicability of using recycled aggregate for the development of pervious concrete and for mitigating liquefaction and reliquefaction effects. The dynamic behaviour of developed recycled aggregate-based pervious concrete pile is compared with natural aggregate-based pervious concrete pile. The study attempts to explore the inherent material properties of pervious concrete keeping permeability equivalent to conventional stone columns but with improved mechanical characteristics with enhanced pore water pressure ratio reduction and soil displacement reduction efficiency under repeated incremental acceleration loading conditions. For testing, 1g shaking table tests were performed with 01 g, 02 g, 03 g and 04 g acceleration loading with 5 Hz frequency. The outcomes obtained from this experimental study infer that recycled aggregate-based pervious concrete pile exhibits a superior performance compared with natural aggregate-based pervious concrete pile. Overall, the use of recycled aggregate found sustainable approach for developing pervious concrete pile and found effective ground improvement application against liquefaction and reliquefaction hazards.

When a soil is subjected to cyclic loading, there are changes in the material's geomechanical behaviour that need to be characterized before safely designing any future projects. In terms of cyclic loading, it is important to characterise not only the failure of the soil but also its behaviour before failure, in particular the yield point and the elastic behaviour of the material. This study examines the effects of the number of loading cycles on the behaviour of a chemically stabilised soft soil with a particular focus on the yield surface. To this end, a series of triaxial tests were performed on specimens, previously or not subjected to a different number of loading cycles (1,000-100,000). The results were analysed in terms of the evolution of accumulated permanent axial strain, the yield surface and stress-strain behaviour. It was observed that an increase in the number of loading cycles promoted: an increase in the permanent axial strain, an increase in the undrained resilient modulus, a shrinkage of the yield surface but its shape is maintained, and there is a small increase in the peak strength of the stabilised soil explained by the strain hardening effect induced by the cyclic loading.

This paper critically evaluates and proposes innovative approaches to address the technical challenges associated with extracting existing piles and backfilling the associated boreholes, specifically in the context of Japan. Japan's rapid post-war economic growth has resulted in an infrastructure that is now aging, necessitating the demolition and subsequent reuse of structures. The prevalent use of pile foundations in soft soil conditions in Japan presents unique challenges following demolition, including differential settlement and complications for future construction on the same site. Current practices in Japan for pile removal are outdated and rely heavily on field experience without the support of standardized guidelines, leading to unresolved issues in improving the removal process. This paper provides an in-depth review of the status of technological advances in pile extraction and removal, as well as the development of backfill materials, with a focus on Japan's unique geological, demographic, and urban development factors. It highlights the risks associated with the traditional wire rope method and presents an innovative pile tip gripping and lifting method that aims to improve safety and efficiency by minimizing friction and preventing accidents. It also discusses the critical role of backfill treatment in preventing subsidence and outlines the performance requirements for fill materials, emphasizing the need for materials that provide uniform strength, prevent material segregation, and resist groundwater infiltration. Specifically, the paper discusses the development of cement-based fillers for borehole backfilling in Japan and demonstrates the effectiveness of sodium carbonate and thickeners in improving the physical and rheological properties of cement slurries. Finally, the paper emphasizes the urgent need for innovative technologies and methodologies for pile extraction, removal, and borehole backfilling in the Japanese context, highlighting their importance in ensuring safe, sustainable, and efficient land use in urban areas while addressing environmental concerns and stakeholder interests in land transactions and construction projects.

The soil arching effect is the key mechanism for load transfer in pile-supported reinforced road (runway) foundations. In order to investigated the formation and evolution process of soil arching effect in the whole process of embankment filling and soft soil foundation consolidation, a three-dimensional hydro-mechanical coupled numerical model of PHC pile reinforced soft soil runway foundation was established based on the foundation treatment project in Pudong Airport. The variation laws of soil settlement, pore water pressure, and pile soil stress were analyzed, and the influence of pile spacing was considered. These data from both numerical simulation and field test indicate the soil arching effect in the foundation reinforced by PHC piles and preliminary reveal the evolution of soil arching in the process of embankment filling and soft soil foundation consolidation. The preliminary results encourage the authors to continue this research to investigate the evolution of soil arching under aircraft dynamic loads through adding a more suitable constitutive model or subroutine in this numerical model.

The knowledge graph based on research papers can accurately identify and present the latest developments in scientific and technological (S&T) innovation and is of great significance for supporting strategic decision-making relating to S&T innovation in undeveloped areas. Based on the international research papers produced in Gansu Province during the 13th Five-Year Plan period (2016-2020), five metrics, including the number and characteristics of papers, co-authors, main publications and their fields, major supporting institutions, and main research areas, are established herein. The results indicate that: (i) the total of 29,951 papers were published, which is about 2.89 times that in 2010-2015; (ii) Gansu Province collaborated with 149 countries/regions globally; (iii) the top 5 journals in terms of the number of papers were Medicine, Scientific Reports, RSC Advances, Science of the Total Environment, and Physical Reviews D; (iv) the funding sources were mainly from the national level; and (5) the top 5 research areas were chemistry, engineering, physics, material science, environmental science, and ecology, which accounted for 64.7% of all papers. Finally, the present study puts forward some recommendations for the decision-making process in the strategic layout of S&T innovation in Gansu Province.