RITES

A nearby construction with a pile foundation in an urban area can cause possible damage or an operational safety concern to the existing tunnels. The response of the tunnel will depend on the relative location of pile tip as compared to the existing tunnel depth. This paper describes an experimental investigation carried out in the laboratory to examine the effect of pile loading on the existing tunnel in Delhi silt. A small-scale testing facility was designed and built to investigate the influence of pile loading in the close vicinity of the existing tunnel. Dimensions of the model tunnel and pile were arrived at based on the physical scaling laws. The model tunnel (outer diameter of 150 mm with thickness of 0.5 mm) and piles (outer diameter of 25.4 mm with thickness of 1.0 mm) are made up of aluminum. Tests were carried out in a fabricated model steel tank (1,100 mm wide, 1,600 mm long, and 1,200 m deep). Experiments were performed at various stages of pile loading at a separation distance of 1.0, 1.5, and 2.0 times the tunnel diameter from its axis. Results indicate that the strain in tunnel lining is significantly affected by various stages of pile loading when the row of pile is placed within the distance of 12 times the pile diameter from the axis of the tunnel. Three-dimensional numerical simulations of model experiments were also carried out, which fairly predicted the phenomena measured in the experiments.

This paper describes an experimental investigation carried out in the laboratory to examine the effects of basement raft excavation and loading on an existing tunnel in Yamuna sand. A smallscale testing facility was designed to simulate the process of basement excavation and installation of basement raft with retaining wall in close vicinity to an existing tunnel. A simplified tunnel excavation system was also designed to simulate tunnel-excavation-induced stresses. Dimensions of model tunnel, sheet pile wall, basement raft, and retaining wall were arrived at after applying the physical scaling laws on prototype dimension using a scale factor of 40. The dimensions of the tunnel and raft foundation were decided based on the stressed zone of soil mass from the edge of the foundation and tunnel periphery. Experiments were performed for different geometrical configurations of raft and tunnel. Results indicate that the circumferential and longitudinal strains at different locations of tunnel lining are significantly affected by various stages of construction/excavation and raft loading. This effect is seen more at crown level when the distance between tunnel and raft is short. The critical zone of influence is found in the region enclosed such that the raft loading is at a clear distance equal to diameter of the tunnel on either side of tunnel axis and strains in tunnel lining are measured up to three times the tunnel diameter on either side from the center line of raft loading. Results further indicate that the magnitude of circumferential strain induced at different cross sections of the lining is larger than the magnitude of longitudinal strain. A numerical analysis was conducted to simulate the experiments using PLAXIS 3D, which fairly predicted the measured phenomena. Thus, it is recommended that the site-specific quantification of the influence of new construction on tunnel lining is very much essential.

Implementation of sustainable urban mobility solutions is key to address congestion challenges in India. To promote sustainable urban mobility, intermodal transit hubs (IMTHs) catering to various transit modes have emerged as one of the successful strategies, as it helps change the mobility pattern of the city and reduce traffic accidents and greenhouse gas emissions. Public and private transport operators, such as KSRTC and APRTC, cater to the intercity passenger demand in Bengaluru. Presently, the intercity buses travel all the way to the city centre, which operations result in duplication of services as well as traffic congestion within the city. The IMTHs need to be developed at the city’s periphery to avoid duplication of services and provide for seamless transfer of passengers to and from the city via intra-city modes available at IMTHs. The aim of the present study, therefore, is to identify suitable sites for the development of IMTHs at different locations on the periphery of Bengaluru. A multi-criteria approach has been adopted to evaluate various identified sites (land parcels). The evaluation parameters have been classified under several categories based on the site characteristics, such as area, transit operations, connectivity, economic development and constructability. Based on reconnaissance surveys and secondary data, the scores are assigned on a Likert scale to each potential site, and they are ranked based on the number of categories in which the site qualifies. This paper concludes with a recommendation of one most feasible site for each location based on evaluation results for implementation of the IMTH.

In last few years, application of GIS technology in highway and transportation engineering field increased substantially in India. In the present study, GIS has been used to develop a user-friendly road information system for State Highway Network in state of West Bengal, India. Objective of the study is to prepare a “Base map” to have all the traffic, road, and structure features mapped into a GIS platform. This map will provide the basic platform for all spatial features of the road and structure assets with an integrated database for storing attributes of the data features and screening and ranking of developmental requirements and to prioritize resource allocation for such development. The present paper demonstrates with the help of data collected from State Highways of West Bengal that GIS can be used as a useful tool for developing an interactive road information system.

With ever‐growing populations, cities are increasingly interested in ensuring a well‐functioning food system. However, knowledge of variation between individual city food systems is limited. This is particularly true in countries such as India, experiencing significant issues related to food security and sustainability. This paper advances the understanding of urban food systems, by analyzing the unique food systems of nine cities within India, through the integration of multiple city‐specific data sources including demand of residents, visitors and industries, and commodity‐specific supply chains to assess nutrition, environmental impact, and supply risk. This work finds a large degree of intercity food system variability across multiple food system characteristics. Specifically, levels of undernutrition vary, with the percentage of city populations who are underconsuming protein ranging from 0% to 70%, and for calories 0% to 90%. Environmental impacts (consumptive water loss, land use, and greenhouse gas emissions) of urban food demand also show variation, largely influenced by differing composition of residential diet. Greenhouse gas emissions are also largely influenced by location of production and spatially informed energy intensity of irrigation. Supply chain distance (“food‐miles”) also vary by city, with the range of 196 (Pondicherry) to 1,137 (Chennai) km/Mg—shorter than more industrialized nations such as the United States. Evaluating supply chain risk in terms of water scarcity in food‐producing regions that serve city demand finds production locations, on average, to be less water‐scarce than the watersheds local to the urban environments. This suggests water‐intensive agriculture may at times be best located at a distance from urban centers and competing demands.