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Safe snd Efficient Method of Blasting for Excavation of a Cross Drift and Widening of Underground Machine Hall to its Full Width — A Case Study
Published in C.V.J. Varma, A.R.G. Rao, Tunnelling Asia ’97, 2020
R.B. Singh, M.M. Singh, P.K. Singh, B.B. Dhar
From the geological investigations, it is indicated that at the power house location and in the area to its northwest in which all the auxiliary tunnels lie, there is a zone of Amygdaloidal Basalts from KRL 128m to KRL 182m. The amygdaloidal basalts are unjointed and impervious when fresh and because of absence of divisional planes, are stable in all kinds of cut and excavations. This is a very favourable feature as the entire excavation of the power house will lie in Amygdaloidal Basalts and will be trouble free. The crown of the machine hall is at KRL 161.75 m.
Identification of critical watershed using hydrological model and drought indices: a case study of upper Girna, Maharashtra, India
Published in ISH Journal of Hydraulic Engineering, 2021
The selected study area lies on the major tributary of the Tapi River i.e Gir River in the west southern part the Tapi basin, India. The Gir River originates at Kem peak in the Western Ghats and merges with Mausam River in Malegaon. It contributes 15% of the drainage area in the main Tapi river. The study area is situated in the western hilly region between the north latitude 20º18ʹ-20º84ʹ and west longitude 73º70ʹ-74º75ʹ in Nashik district of Maharashtra state. The Chankapur and Girna dam are the two dominant hydraulic structures present in the study area. The Girna dam was constructed in the year 1969 having a live storage capacity of 523.55 MCM. It covers an area of 4729 sq.km. The index map of the study area which lies in the semiarid ungauged region along with its drainage network is shown in Figure 1. The study area receives the south-west monsoon in the month of June and withdraws in the month of October. There are three rain gauge station present in the study area. The calculated annual average rainfall and evapotranspiration of the study area for the three decades are 639 mm and 1652.22 mm, respectively. Consequently, the catchment faces less rainfall as compare to evapotranspiration losses. Thus, it come under semiarid region. Figure 2 represents the study area which has a large number of irrigation-based projects and hydraulic structures. The use of water in the upstream side of the Girna dam reduces the inflow coming into the dam (GoM 2015). The districts of Jalgaon and Nashik of Maharashtra state are covered under the present study area, and they use Girna water for irrigation purpose (Jain et al. 2007). The upper Girna soil mostly come in ‘A’ and ‘B’ type hydrological group (Subramanya 1994). The hydrogeology represents the movement of groundwater in the soil and rock i.e earth crust. The groundwater level for the post monsoon data sets are varying from the range of 3 to 19 m ending with more infiltration (Ramkar and Yadav 2018). Figure 3 represents the hydrogeology map of the upper Girna. It possesses Deccan trap formation (i.e basaltic lava flows of upper Cretaceous to lower Eocene) and recent alluvial pocket formation on the banks of the tributary of Gir River at Thengonda, Satana, Vakhari, Khalp, Bhramgaon. The lithology of the study area has amygdaloidal trap basalt. They become feasible due to the joints, fractures, and cracks in a various shape and combined to form spheroidal weathering which is observed in the study area. The present cracks and fractures are responsible for interflow through rocks after the rainfall-runoff process. The major tributaries of Gir River are Aram, Punad, Panzan, Mausam, Manyad, Titur, Anjani, Hivara, and Bahula (Jain et al. 2007; CWC 2014).