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Slope failures associated with large-scale displacements and high strains in geomaterials have often resulted in large loss of life and properties in the Himalayan terrain. These slope failures bear a substantial relation to high-intensity rainfall events [1].One such slope is located at south portal of Rohtang tunnel, numerous slope failures due to the effect of fluctuating water table and rainfall events had already occurred. This paper describes variation in strength reduction factor (SRF) by a two-dimensional finite element based numerical modelling under four dominate strength reduction parameters. A total of one thirty-five analysis has been performed to obtain SRF values considering two sets of parameters. Three type of rocks constituting the slopes are Phyllitic quartzite, Quartzitic phyllite and Migmatite gneiss. Physico-mechanical behaviour of these rocks are investigated as per ISRM and BIS standards. The role of pore water pressure, joint inclination, slope angle and water table within the slope and its effect on failure is discussed in this paper. [ABSTRACT FROM AUTHOR]

• Extensive geotechnical characterization of the soil from landslide slip surface helps evaluate the failure mechanism of landslide. • High-intensity rainfall, unplanned vertical cuts and slopes have witnessed the loss of lives and substantial monetary losses during the southwest monsoon in Kerala, India, in 2018. • Importance of locally available sustainable green martial uses in engineering practices. • The numerical analysis confirmed that the vertical cut stabilization with coir geotextiles is safe during high-intensity rainfall. This paper presents laboratory and numerical analysis of vertical cut failure due to rainfall-induced landslide resulting in building failure that led to the death of nine people in Kerala, India, on August 15, 2018. The residual shear strength parameters are evaluated by the ring shear test. The soil water characteristics curve (SWCC) is developed by unsaturated soil strength parameters. The slope stability and infiltration analysis are carried out with limit equilibrium and finite element methods, respectively. The infiltration analysis is carried out by considering three different rainfall patterns on the slope as low, medium, and high intensities. The study includes a two-stage numerical analysis of vertical cut. Firstly, vertical cut analysis with and without rainfall effects and second, the analysis of vertical cut using coir geotextile as reinforcement with rainfall effects. The study emphasized the utilization of locally available coir geotextiles as a reinforcement for slope stabilization. [ABSTRACT FROM AUTHOR]

This paper presents the dynamic response analysis of Talcher pond ash embankment in India, considering both full saturation and existing water table condition subjected to earthquake excitation. Static and cyclic triaxial tests were performed to determine the parameters required for the dynamic response analysis of the existing pond ash embankment. From the cyclic triaxial test, it is observed that Talcher pond ash is susceptible to liquefaction. A two dimensional nonlinear finite element analysis using Open System for earthquake engineering simulation (OpenSees) has been carried out to study the dynamic response analysis of the existing embankment. The pre and postprocessing phases have been done using GiD 7.2 software. The North East India earthquake, May 08, 1997 (Motion 1) and North East India earthquake, Aug 06, 1988 (Motion 2) have been used as the input motion for the dynamic response analysis. The model has been validated with the results of cyclic triaxial test performed on Talcher pond ash. From analysis, it is observed that under full saturation condition, the maximum horizontal and vertical displacement below the slope of the embankment is 4.505 m and 3.247 m respectively. Also the pore pressure ratio below the slope is observed more than unity. The pond ash embankment is not safe against liquefaction and lateral spreading under full saturation condition. However, under existing water table condition the embankment is safe against liquefaction. [ABSTRACT FROM AUTHOR]

Abstract: Component failures due to excessive flow-induced vibration are still affecting the performance and reliability of nuclear power stations. Tube failures due to fretting-wear in nuclear steam generators, and vibration related damage of reactor internals are of particular concern. In the Indian nuclear industry, flow induced vibrations are assessed early in the design process and the results are incorporated in the design procedures. In this paper the details of flow induced vibration studies on internals like liquid zone control unit and poison injection units of heavy water filled calandria of 700MWe Indian pressurized heavy water reactor is given. This includes computational fluid dynamics studies from which the velocities are extracted for the components lying inside the calandria. With these velocities as input, further studies are performed to predict the dynamic behavior of these components. Results of these calculations as well as conclusions derived from this investigation are presented. Based on the studies it has been established that flow induced vibration is not a concern in the present design of 700MWe calandria internals. [Copyright &y& Elsevier]

Abstract: Cleats and fractures in coal of Barakar Formation in Jharia coalfield, India have been mapped from the coal exposures around 21 opencast and 2 underground coal mines. Macro-cleat distribution, observed from this mapping is similar to that of well-developed coalbed methane (CBM) basins. The opencast coal mines are distributed in SE–NW direction along the boundary of the sickle shaped Jharia coal basin. Permeability of CBM through coal seams is the most critical property deciding the viability of any CBM field. It is largely controlled by the degree of cleat development. This paper discusses cleat orientation and other structural features, observed in the outcrops of 14 major coal seams in Jharia coalfield and its directional relationship with the in-situ stress (SH) orientation pattern. Cleat orientation is found to vary laterally within same seam at the different locations, distributed from the south-east part to the north-western part of Jharia coalfield. Face cleat orientation of the 21 opencast coal mines varies from N45°E to N45°W. Change of orientation of cleat, observed around the mining areas is related the orientation of fault systems and orientation of igneous intrusions occurring within the coal bearing packet. Maximum in-situ horizontal compressive stress (SH) direction is found to be parallel to the face cleat orientation in normal faulted basin like Jharia coalfield. An overall, NNE–SSW and NW–SE orientation of the SH direction is predicted in the coal mines from cleat orientation mapping. SH orientation is locally modified at places, close to the tectonic features and igneous intrusives. Finite element stress modeling is carried out near Moonidih area. Cleat orientation predicted stress direction matches well with the finite element stress results. [Copyright &y& Elsevier]

Abstract: This paper presents different types of premature failures observed during full-scale testing of Transmission line towers at Tower Testing and Research Station, Structural Engineering Research Centre, Chennai. Failures that have been observed during testing are studied and the reasons are discussed in detail. The effect of non-triangulated hip bracing pattern and isolated hip bracings connected to elevation redundants in ‘K’ and ‘X’ braced panels, on tower behaviour are studied. The tower members are modeled using beam-column and plate elements. Different types of failures are modeled using finite element software and the analytical results and the test results are compared with various codal provisions. The non-linear finite element analysis program NE-NASTRAN has been used to model the elasto-plastic behaviour of towers. Importance of secondary member design and connection detail in overall performance of the tower was studied. Non-linear finite element analysis is useful in understanding the system behaviour and for prediction of failure pattern and ultimate load. Based on the test results the importance of studying the failures is highlighted. The need for testing of transmission line towers is emphasized. [Copyright &y& Elsevier]

Abstract: An on-line structural safety evaluation system (BOSSES) has been developed over the years at Bhabha Atomic Research Centre (BARC), India, which is capable of assessing the damage due to creep and fatigue in critical plant components. The system acquires plant transients in real time and processes them to evaluate the stress, temperature and damage distribution in the components and provides information through a visual module. The aim of the paper is to briefly describe the details of the damage assessment methodology adopted by BOSSES with some case studies of real life plant components. [Copyright &y& Elsevier]

• SHM experimental campaign conducted on a multi-arch masonry bridge located in India. • Large longitudinal crack on one of the arches detected with considerable crack width. • SHM monitored with crack growth monitoring and tilting of the spandrels. • Application of two different heavy loads (water tank and hydra crane) located in different positions. • Numerical modelling with advanced full 3D approach with adaptive NURBS FEM in limit analysis. The paper presents some SHM results belonging to a wide experimental campaign conducted on a multi-arch masonry bridge located near Mumbai (India), exhibiting a large longitudinal crack on one of the arches and the corresponding advanced numerical evaluations carried out with a NURBS kinematic limit analysis approach, used to assess the stability of the arch subjected to the passage of heavy traffic loads. The masonry bridge is a three-arch structure built during the mid-19th century by British engineers to connect Bombay with the inland of the Indian subcontinent. At present, it is characterized by a heavy state of degradation especially in one of the arches that requires an immediate evaluation of the safety under the passage of traffic loads and possible ideas of interventions to strengthen the structure, in order to avoid the propagation of deep cracks along the longitudinal direction. The adopted SHM includes the crack growth monitoring and tilting of the spandrels under the application of two different heavy loads (a water tank truck and a hydra crane) located in different positions of the arch. Numerical modelling is carried out with a full 3D approach with NURBS finite elements in limit analysis that takes into account the pre-existing crack opening and predicts with great accuracy the ultimate loads in different scenarios and the corresponding active failure mechanisms. From experimental monitoring and numerical simulations results, it is concluded that the bridge is still safe under the passage of traffic loads, but approaches the ultimate limit state for some specific configurations of the loads applied. A refurbishment is therefore needed to avoid any further propagation of the cracks up to collapse. [ABSTRACT FROM AUTHOR]

Immediate roof of a longwall panel in India is composed of mostly low quality coal and shale and as a result, several roof fall incidents have occurred in between canopy tip and the face causing delay in production. The mine has several longwall panels and it is expected that similar conditions may prevail in all the panels. Roof-to-floor convergence at the face, shield leg pressure and abutment load in chain pillar are monitored to evaluate the stability of longwall face in terms of displacement as well as stresses. In view of that, a study is conducted to understand the deformation behaviour of roof-to-floor convergence and development of pressure in hydraulic legs after the web cut considering different combinations of main roof thickness, its overhung length behind the shield, and material type and setting load. This paper describes a methodology for estimation of roof-to-floor convergence using 3D finite element models before and after web cut. A statistical procedure is also enumerated for development of a unique roof-to-floor convergence index combining input parameters. For this purpose, a total of 216 3D finite element models are analysed considering Drucker-Prager material nonlinearity and having two legged powered support of 2 × 1152 tonne capacity surrounded by coal, rock mass and goaf. This study also compares the roof-to-floor convergence measured in the field to those estimated using the proposed convergence index. • A 3D powered support is modelled along with coal seam, rock mass and goaf to analyse deformation, stresses and plasticity. • Total of 216 FEM models are developed by varying thickness, length and material type of main roof and setting pressure. • Bar elements are considered to simulate the setting of powered support at desired pressure level in numerical environment. • A new Convergence Index is developed using statistical technique to forecast roof to floor convergence in longwall face. [ABSTRACT FROM AUTHOR]