Faculty Publications

Now showing 1 - 4 of 4

Computer aided slope stability analysis
(2006) Sastry, V.R.; Ram Chandar, K.; Santosh, M.
Primary purpose of slope stability analysis in most of the engineering applications is to provide safe and economic design of slopes that prevent failure. The analysis technique chosen depends on both site conditions and potential mode of failure which depends upon the rock mass characteristics. Various slope stability analysis techniques include physical, numerical and analytical methods. Physical modeling is a time consuming process and a costly affair, while analytical method involves past experiences, it is site specific and depends upon various parameters which are difficult to quantify. Numerical analysis with sophisticated softwares provides an accurate solution within short duration. This paper presents an in-house developed software package called "V-slope" to analyze and interpret the slope with options for suggesting suitable safety measures based on the nature of slope. Slip circle and tension crack techniques were considered for analysis. The slope profile for different factor of safety (FOS) values will be displayed on the screen for easy understanding. In case the FOS is lower than the required, the V-slope gives suggestive measures. In case of temporary slopes the only way by which slope failure can be prevented is by decreasing the slope angle and in such cases the program gives additional volume of material to be excavated and the likely additional cost incurred for various slope angle options. For permanent slopes, option is provided for designing the soil nails, i.e. number of bolts required, length, diameter and spacing of the bolts etc. Finally the V-slope is compared with a comprehensive commercial software package Slide and the results were found very much satisfactory.
Behaviour of large underground cavern during construction in himalayas - a case study
(CAFET INNOVA Technical Society cafetinnova@gmail.com 1-2-18/103, Mohini Mansion, Gagan Mahal Road, Domalguda, Hyderabad 500029, 2014) Naik, S.R.; Sastry, V.R.
Construction of large underground caverns in Himalayas is challenging due to complex geological and insitu stress conditions. Understanding the behaviour of such caverns during construction stage is possible only with extensive instrumentation. A case study of a large cavern under construction in Himalayan region in Bhutan is considered. Results from various types of instruments are discussed in this paper. Instrumentation data shows that Himalayan rock mass particularly with phyllitic quartzite exhibits large deformations thus requiring careful selection of support and excavation methodology. © 2014 CAFET-INNOVA TECHNICAL SOCIETY.
A numerical modelling approach to assess the behaviour of underground cavern subjected to blast loads
(China University of Mining and Technology, 2018) Kuili, S.; Sastry, V.R.
The paper gives an insight into the behaviour of large underground caverns which are subjected to blast loads. Caverns are generally constructed in hard rock formation which compels us to use blasting methods for the excavation works. Comparative study was done between models with intact rock mass and discontinuities to assess the stability of cavern as a result of blast loads. Numerical modelling was performed with 3 dimensional distinct element code (3DEC) to analyse the performance of cavern walls in terms of displacement and to compute peak particle velocities (PPV) both around the cavern periphery and at surface of models. Results showed that the velocity wave with higher frequency exhibited large displacements around the periphery of cavern. Computation of PPV showed that model with horizontal joint sets showed lower PPV in comparison to model with intact rock mass. PPV values were also analysed on the surface for model consisting vertical joints spaced at 4 m intervals. Comparative study of PPV on surface vertically above the blast location between models with horizontal joints spaced at 4 m and vertical joints at 4 m intervals were conducted. Results depicted higher magnitudes of PPV for model with vertical joints in comparison to model with horizontal joints. © 2018
A Numerical Modelling Approach to Assess Deformations of Horseshoe Cavern on Account of Rock Mass Characteristics and Discontinuities
(Materials and Energy Research Center, 2023) Kuili, S.; Sastry, V.R.
Caverns are massive underground openings excavated for purposes like defense installations and nuclear waste disposal which becomes challenging for weak strata consisting of fractured rock masses and may result in future calamities. This study is dedicated to ascertain stability of a horseshoe cavern in different types of granitic rock masses as well as fractured rocks. Two different types of granitic formations are accounted and displacements obtained along cavern periphery have been illustrated in the preliminary part of this study. An increment in vertical displacement at the crown of 260% and lateral displacement of almost 170% for both walls were observed for moderately weathered rock. Further, implications due to orientation and frequency of joint sets on the displacements incurred has also been explored. This study acquires its novelty by considering combinations of joint sets with varying spacings for investigating their implications on cavern walls. Presence of discontinuities depicted that horizontal joint spaced closely increased the deformation magnitude which reduced with decrement in joint frequency. Subsequently, along with horizontal joints at 4m interval, vertical and oblique joints sets were also incorporated at different frequencies. Consideration of vertical joints at 2m spacing with horizontal joints resulted in 313.2% increase in vertical displacement at cavern crown as well as 340% and 363% increase in lateral deformation at the left and right wall, respectively in comparison to intact rock. In case of oblique joints spaced at 2m with horizontal joints, increment in vertical deformation at the crown proliferated to 329% in comparison to intact rock. © 2023 Materials and Energy Research Center. All rights reserved.

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