Hydropower

What are the important of rock engineering in hydropower development? Draw a layout of hydropower plant with its main element. List any three problems caused by groundwater in rock engineering projects. Also, mention one method for estimating or measuring groundwater inflow in tunnels.

Explain the intact rock and rock masses on the basis of Hudson and Harrison. What are the factors that affect the physical properties of rock mass? How can you utilize the generalized Hoek-Brown criterion for the strength of rock mass properties? List the different physical properties of rock mass and explain any two briefly.

Explain the origin of in-situ rock stresses and describe how these stresses affect the stability of underground openings. Write down the different stability problems due to stresses. From the parameters given below, find the magnitude of tangential stress at the roof and wall of $a^n$ unlined pressure shaft. Roof factor = 3.5, Wall factor = 2.5, Vertical stress = 12 MPa, Poisson's ratio ($\nu$) = 0.25.

Calculate the water flow into tunnel for following conditions: Length of tunnel = 1840 m; Active head = 0.86 MPa; Distance between length axis and groundwater table = 92 m; Unit weight of water = $9.81{\text{kN/mm}}^3$; Equivalent radius = 5.54 m and Hydraulic conductivity = $10^{-13}\text{m/s}$

Why engineering geological investigation is necessary for underground structures? What are the activities that should be carried out during construction phase investigation?

What is the purpose of rock mass classification in underground construction? Write down the RMR-support method in brief. For a new road cut, $a^n$ engineering geological survey determined the following parameters for the rock mass. Calculate the RMi value from the observed value: Intact Rock UCS (${\sigma }_c$) = 80 MPa Joint Condition Factor ($j_c$) = 1.4 Volumetric Joint Count ($J_v$) = 14 ${\text{joints/m}}^3$.

Describe about the shallow seated opening for underground. What are the challenges in shallow seated underground opening and its associated problems? What type of the main slope failure occurs in Nepal? What are the general conditions for sliding and toppling of a block on $a^n$ incline plane?

Briefly describe the commonly used rock support methods in underground structures. Mention any two methods used to achieve improved and cost-saving solutions in the construction of underground high-pressure tunnels and shafts. Draw the distribution of tangential stress surrounding the circular opening of tunnel for the following conditions and critically discuss the influence of rock stress anisotropy for above planned structure. (a) ${\sigma }_1/{\sigma }_3=16/16\text{ (MPa)}$ (b) ${\sigma }_1/{\sigma }_3=16/10\text{ (MPa)}$ (c) ${\sigma }_1/{\sigma }_3=16/4\text{ (MPa)}$