Open Access

Articles

Article ID: 618

Study on compaction characteristics and discrete element simulation for rubber particle-loess mixed soil

by Wen-qi Kou, Jian-guang Bai, Hai-jun Li, Qing-hong Liu

Insight - Civil Engineering, Vol.7, No.1, 2024; 27 Views, 25 PDF Downloads

The rapid surge in traffic volume in China has resulted in a substantial accumulation of waste tires. By harnessing the lightweight and deformable characteristics of tire rubber particles, they are combined with soil to form rubber particle-loess mixed soil, which is progressively being embraced in civil engineering as a pivotal approach towards attaining green and sustainable development. In this study, waste tire rubber particles were integrated into loess to generate rubber particle-loess mixed soil, and compaction tests were conducted to investigate its compaction characteristics. Furthermore, PFC 3D (Particle Flow Code 3D) was utilized for simulating the bearing ratio test of rubber particle-loess mixed soil, thereby validating the feasibility of numerical simulation for calculating CBR (California bearing ratio) values and exploring the relationship between micromechanical characteristics and macroscopic characteristics of such mixtures. The findings indicate that the maximum dry density of rubber particle-loess mixed soil significantly decreases with an increasing content of rubber particles. The utilization of PFC 3D discrete element software proves efficacious in examining the bearing capacity of this mixture. Notably, when 20 mesh rubber particles constitute 20% by volume, the CBR value reaches its pinnacle and exhibits optimal bearing capacity. From a micromechanical perspective, the variation in internal porosity of rubber particle-loess mixed soil is positively associated with changes in macroscopic optimal water content, and negatively associated with changes in macroscopic CBR value. incorporating rubber particles enhances resistance against external forces while diminishing deformation within loess. This study provides a guidance for the efficient utilization of waste tires and the improvement of loess’s characteristics.

Open Access

Articles

Article ID: 616

Engineering geological and geotechnical evaluation of Sathya Sai Prasanthi Nilayam railway tunnel, Andhra Pradesh, India

by A. K. Naithani, Prasnna Jain

Insight - Civil Engineering, Vol.7, No.1, 2024; 17 Views, 12 PDF Downloads

Detailed engineering geological investigations were carried out for a railway tunnel which was constructed more than two decades ago. 3D engineering geological mapping was carried out using Brunton Compass and Total Station Surveying instruments in 1:100 scale. Coarse-grained pink and grey granite, hornblende-biotite gneiss and dolerite dyke of Archaean age and Lower Proterozoic age were mapped. Rock mass was intersected by sub-horizontal, inclined, and vertical joint sets, which were continuous and persistent, smooth, and planar with thick filling of decomposed and crushed sheared material or with thin coating of clay material. Based on the Q-system, rock mass was classified into different classes. On the basis of large-scale engineering geological mapping and Norwegian Method of Tunnelling, a support system was recommended which includes rock bolt, fibre reinforced shotcrete, grouting and reinforced ribs of sprayed concrete and the same is implemented by the agency. As per the best knowledge of the authors, reinforced ribs of sprayed concrete are first time used for transportation tunnels in India and it will be more effective if it will be compared with ISMB or Lattice Girder.

Open Access

Review

Article ID: 608

Vulnerabilities of water-energy and food nexus in cities of digital era

by G. Fivos Sargentis, Matina Kougkia

Insight - Civil Engineering, Vol.7, No.1, 2024; 454 Views, 104 PDF Downloads

The edifice of civilization stands on water-energy-food nexus, speech, trading management and complexity. This paper, presents a mini review of these issues which are the foundations of civilization, and discusses their role in social prosperity. Recent year public discussion emerges that an electromagnetic pulse (EMP) could strike cities due to natural or artificial reasons therefore, we attempt to describe the impact of an EMP from the viewpoint of civil engineering. To do so, we analyze the fundamental parts of civilization in present, their roles, and their functions. Analysis estimates that an EMP will not regress cities of developed world to the 1970s or even in the Middle Ages, but rather before the agrarian era. It is noted that while the developed world will be more vulnerable, the least developed countries, could exhibit more resilience. Additionally, this paper considers the way societies and cities could demonstrate more resilience, framing the need for further research such as: technological adaptation; study and simulations of related scenarios; design of water-energy-food nexus for survival clusters; resilience measures for money, economy, communications, and trading. As we have a very small timeframe of data (less than 200 years) of the appearance and the effects of EMP, we have to study it, even if the wish is that we will never confront it. It seems unreasonable for our narcissistic and wonderful civilization to behave like ostrich hiding its’ head in the sand in order to be hidden by this threat.